ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (7,131)
  • Chemical Engineering  (7,131)
  • Animals
  • Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics  (7,131)
Collection
  • Articles  (7,131)
Source
Keywords
Publisher
Years
Topic
  • 101
    Electronic Resource
    Electronic Resource
    Change of molecular weight distribution of statistical poly(styrene-co-acrylonitriles) with compositio of copolymer (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1348-1352 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Statistical poly(styrene-co-acrylonitrile) (SAN) copolymes with varying mole fractions of comonomer units have been synthesized in a batch reactor. The intrinsic viscosity and gel permeation chromatography (GPC) patterns of model copolymer samples were the basic experimental results. Chromatographic patterns of SAN copolymer samples were converted into molecular weight distributions and afterwards fitted to the theoretical distribution functions. The correlation between the composition of copolymers and the best fitted model distribution (Schulz's two parameters distribution in this case) was established. The treatment of data shows that parameter α is inversely proportional to the content of acrylonitrile units in the sample and indicates the molecular weight interval. Parameter b shows the invariability of the molecular weight distribution shape.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351704
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 102
    Electronic Resource
    Electronic Resource
    A non-Markovian model of desorption (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1369-1374 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The desorption kinetics of small hydrocarbon molecules in a low-density polyethylene (LDPE) film has been simulated via the continuous time random walk approach. A scaling relation between the amount of penetrant remaining in the film during the final stage of the process and the time has been obtained. A constant scaling exponent was obtained for various hydrocarbon penetrants in LDPE. The mutual relation between phenomenological and statistical models has been exploited.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351707
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 103
    Electronic Resource
    Electronic Resource
    Novel diagnosis of thermal deterioration for organic insulating resins by optical loss analysis (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1375-1380 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: We propose an “optical loss analysis” as a novel nondestructive diagnosis for the thermal deterioration of insulating resins. Using an alkyd resin film, the optical absorptin loss per unit optical path length and the glass transition temperature (Tg, DMA) by dynamic mechanical analysis were measured during heating tests. At longer heating times, values of the optical absorption loss and the Tg, DMA increased concurrently. By rescaling the heating time as a reduced time as a reduced time, a master curve of the deterioration for the resin was obtained. Consequently, when thermal stress is the main cause of the deterioration, one can estimate the degree of deterioration and theoretically the residual lives of resins using this optical loss analysis.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351708
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 104
    Electronic Resource
    Electronic Resource
    On the measurement of residual stress in plastic pipesAcknowledgment is given to the 13th International Plasic Fuel Gas Pipe Symposium, held Nov. 1-4, 1993, in San Antonio, Texas, for permission to publish this work. (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1381-1386 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Recent work on the determination of residual stress in drawn pipes has revealed an error in previous methods used. Such pipes have residual stresses very different from those induced by melt extrusin during conventional pipe processing. In particular, it appears that there are considerable compressive stresses at the bore, and the hoop and axial values are not equal. In an attempt to measure these values, tests were performed on slit rings of varying length, and a pronounced dependence of ring overlap on length was observed. This was contrary to previous assumptions, and a corrected version of the analysis has been developed, which enables the true hoop and axial stresses to be determined by testing rings of various lengths. For isotropic pipes, it has been shown that hoop and axial stresses are roughly equal. Previous results obtained on thin pipe rings can now be corrected by multiplying by the factor 1/(1-v). For anisotropic drawn pipes, a combination of rings and thin axial strips is used to determine the residual stresses. These pipes can show remarkably low stresses at the bore, which may play a significant part in determining their performance.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351709
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 105
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351801
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 106
    Electronic Resource
    Electronic Resource
    Fracture toughness of acrylonitrile-butadiene-styrene by J-integral methods (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1433-1439 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The fracture toughness of acrylonitrile-butadiene-styrene (ABS) was determined by three J-integral methods, ASTM E813-81, E813-87, and by hysteresis. The critical J values (J1c) obtained are fairly independent of the specimen thickness, ranging from 10 to 15 mm. ASTM E813-81 and hysteresis methods result in comparable J1c values, whereas the ASTM E813-87 was ∼40% to 50% higher. The critical displacement determined from the plots of hysteresis (energy or ratio) and the true crack grow length vs. displacement are close. This indicates the critical displacement determined by the hysteresis method is indeed the displacement at onset of crack initiation, and the corresponding J1c represents a physical event of crack initiation. The elastic storage energy. The input energy minus the hysteresis energy, is the most important factor in determining the onset of crack initiation. The critical elastic storage energy (at the beginning of crack growth) was found close to the J1c obtained from the E813-81 or the hysteresis method.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351803
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 107
    Electronic Resource
    Electronic Resource
    Effect of mean strain on the cyclic deformation and stress relaxation in polypropylene (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1455-1460 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The influence of mean strain Changes in the range from 0 to 4% on the cyclic deformation and stress-relaxation properties is investigated using rod specimens of polypropylene. An extensometer measures and controls the axial strain in a closed-loop, electrohydraulic, servocontrolled mechanical testing machine. The hysteresis loop at different numbers of cycles N of N = 35, 45, and 50 are irregular in shape, and the tensile portion decreases in size as the number of cycles was increased. The stress value of the tensile portion for three mean strains of ∊m = 1.0%, 2.0%, and 4.0% remains constant, but the value of the compressive portion decreases as the mean strain was increased. The stress level at a strain width of 3% changes little with mean strain. For the strain widths of 5% and 7%, however, the minimum stress levels at N = 35, 45, and 50 increase with increasing mean strain, in contrast to the behavior of maximum stress level. The stressrelaxation tests show that the drop of stress decreases with an increase in number of cycles. The discrepancy in the results of relaxation tests is due to the effect of the difference in strain rates.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351805
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 108
    Electronic Resource
    Electronic Resource
    Interfacial structure in reacting poly(methyl methacrylate)/polycarbonate polymer blends (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1476-1480 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The snall angle neutron scattering (SANS) technique has been used to study the interfacial structure development in poly(methyl methacrylate)/polycarbonate (PMMA/PC) blends through transesterification. We found: (1) Development of interfacial structure through transestrification at the phase separated domain interfaces are observed at T ≤ 200°C. At T ≥ 215°C, because of a higher transesterification rate, the melting of domains is observed together with very weak scattering by interfacial structure. (2) Interfacial thickness ti increases with time and reaches a plateau value of ti at 32.5 ± 2.4 Å and 29.6 ± 3.7 Å for 180°C and 200°C, respectively. (3) The internsity profiles at 190°C and long times shows the formation of spherical domains similar to those reported by Rabeony et al. (1). These may be caused by the crosslinking effect of the transesterification reaction between PMMA and PC.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351808
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 109
    Electronic Resource
    Electronic Resource
    Modification and compatibility of epoxy resin with hydroxyl-terminated or amine-terminated polyurethanes (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1468-1475 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Phenolic hydroxyl-terminated (HTPU) and aromatic amine-terminated (ATPU) PU modifiers were prepared by reacting two different macroglycols (PTMG, polytetramethylene glycol, Mn = 2000, and PBA, Polybutylene adpate, Mn = 2000) with 4,4′-diphenylmethane diisocyanate (MDI), then further coupling with two different coupling agents, bisphenol A or 4,4′-diaminodiphenyl sulfone (DDS). These four types of PU prepolymers were used to modify the epoxy resin with 4,4′-diamino-diphenyl sulfone as a curing agent. From the experimental results, it was shown that the values of fracture energy, GIC, for PU-modified epoxy were dependent on the macroglycols and the coupling agents. Scanning electron microscopy (SEM) revealed that the ether type (PTMG) of PU-modified epoxy showed the presence of an aggregated separated phase, which varied between 0.5 μm and 4 μm in the ATPU (PTMG) and between 1 μm and 1.5 μm in HTPU (PTMG) modified system. On the contrary, the ester type (PBA) PU-modified epoxy resin showed a homogeneous morphology and consequently a much smaller effect on toughening for its good compatibility with the epoxy network. In addition, it was found that the hydroxyl-terminated bisphenol A as a coupling agent improved fracture toughness more than the amine-terminated DDS because of effective molecular weight buildup by a chain extension reaction. The glass transition temperature (Tg) of modified epoxy resin as measured by dynamic mechanical analysis (DMA) was lower in PTMG-based PU than in a PBA-based PU series with the same weight of modifier.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351807
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 110
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351901
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 111
    Electronic Resource
    Electronic Resource
    A method for measuring PVT relationships of thermoplastics using an injection molding machine (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1505-1510 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The objective of this study is to establish a feasible method for generating pressure-specific volume-temperature (PVT) data for thermoplastics on a microcomputer-controlled injectionmolding machine (IMM). This method utilizes the injection barreel of the IMM as a pressure chamber for determining the specific volume of thermopla;stics at various pressure and temperature conditoins. An empirical equation of state based on the Tait equation s used to fit the PVT data of three resins  -  low-density polythelene (LDPE), polystyrene (PS), and acrylonitrile-butadiene-styrene copolymer (ABS). The comparsion between LPDE's PVT data generating from the IMM and from the classical bellows method indicated that the present method can be reasonably applied for determining the specific volume of thermoplastics as a function of presure and temperature.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351903
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 112
    Electronic Resource
    Electronic Resource
    Curing of thermosetting polymers by an external fluid (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1521-1526 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A theoretical model is proposed for curing thermosetting polymers. The following heat transfer mechanisms are taken into account: convection through the heated fluid-mold interface, conduction through the resin, and heat generated by chemical reaction. To study the influence of the convective heat in the curing step of the polymers, different external heating fluids are considered. Several chemical systems are used in the simulation. The results show that an apoxy requires precise control of thermal runaway. Criteria for processability are established and they provide a cycle time without promoting a damaging exotherm.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351905
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 113
    Electronic Resource
    Electronic Resource
    Principal directions as a basis for the evaluation mixing (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1527-1534 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Measures of mixing for laminar flow are developed from basic principles of continuum mechanics for infinitesimal rates of stretch. The entire analysis is performed from the basis of the eigenvalues and principal directions of the appropriate flow tensors. Measuring the rate of line growth, where the line marks the interface between two miscible fluids, in terms of the major eigenvalue provides a direct measure of the maximum rate of mixing. Two efficiency measures for mixing are derived in terms of the eigenvalues and their directions. The creation efficiency of the magnitude of the major eigenvalue as a function of the energy input into the flow field is evaluated. The orientation of the interface to the principal direction qualifies the mixing efficiency in laminar flow. The new theory is used to analyze two-dimensional and three-dimensional channels. The results demonstrate not only the continuum measures for mixing but also extend our present understanding on mixing and provide future directions.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351906
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 114
    Electronic Resource
    Electronic Resource
    The effect of drawing temperature on multi-stage drawn ultra-high molecular weight polyethylene (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1555-1561 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of drawing temperature on multi-stage drawn ultra-high molecular weight polyethylene (UHMWE) fiber, produced by gel spinning, has been studied. Drawing at higher temperature generally gives higher crystal orientation, as expected. The activation energy of drawing increased with the draw ratio and raw 4sequence. It varied at a given draw ratio and draw stage between two temperature ranges, 85 to 115°C and 115 to 135°C. Thus, for the first draw stage, the activation energy is ∼ 19 - 35 KJ/Moe in the range of 85 to 115°C, and ∼ 60 - 99 KJ/mole in the range of 115 to 135°C. In the second stage, the activation energy is 40 KJ/mole in the range of 105 to 115°C and 70 - 99 KJ/mole in the range of 115 to 135°C. In the third stage, the activation energy is ∼ 92 - 100 KJ/mole in the range of 115 to 135°C.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351909
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 115
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352001
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 116
    Electronic Resource
    Electronic Resource
    Polymer research in korea (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1581-1582 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This special issue is dedicated to the current and rapidly growing polymer research in Korea. The isue contains a grouping of typical research studies from Korea. The set is not inclusive, as there are many fine additional research programs under way in Korea. A brief history and comments on several aspects of Korean polymer research may provide a perspective.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352002
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 117
    Electronic Resource
    Electronic Resource
    A cure study on alumina trihydrate reinforced allylester resins by differential scanning calorimetry (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1583-1591 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Allylester prepolymers were synthesized by transesterification, and curing kinetics of alumina tihydrate reinforced allylester resins was studied by means of a differential scanning calorimetry dynamic experiment. The activation energies and the frequency factors of the reinforced allylester prepolymers were estimated by means of Ozawa's and Kissinger's methods. The values determined from the Ozawa method are higher than those from the Kissinger method. The peak exotherm temperature of reinforced allylester resin was shifted to a lower temperature as the concentration of curing agent increased. The peak exotherm temperature as the concentration of curing agent increased. The peak exotherm temperature of reinforced allylester resin was, however, shifted to a higher temperature as the content of alumina trihydrate increased. In the case of the dynamic experiment, both the activation energy and the frequency factor decreased as the concentration of curing agent was increased. Meanwhile, there exist minimum values of both the activation energy and th frequency factor with varying contents of alumina trihydrate.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352003
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 118
    Electronic Resource
    Electronic Resource
    Blends of thermotropic liquid crystalline polyesters and poly(butylene terephthalate): Thermal, mechanical, and morphological properties (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1605-1614 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Blends of poly(butylene terephthalate) (PBT) with three different thermotropic liquid crystalline polyesters (TLCPs) were prepared. The first TLCP (HBH-6) consists of diad aromaticester type mesogenic units and the hexamethylene spacers along the main chain, and the second (TB-S6) is a wholly aromatic polyester TLCP having alkoxy side groups on the terephthaloyl moiety. The last (TR-4,6) is an LC copolymer comsisting of triad aromatic ester type mesogenic units and two differents spacers; tetramethylene and hexamethylene units. Blends of TLCP with PBT were melt spum at different LCP contents and differnt draw ratios to produce monofilaments. For the HBH-6/PBT and TB-S6/PBT blends, the ultimate tensile strength showed a maximum value at the 5 wt% level of LCP in the blends, and then it decreased when the LCP content was increased up to 20%. On the other hand, the initial modulus monotonically increased with increasing LCP content in all cases. The blends with TB-S6 showed the highest tensile properties of the three blends systems. This can be ascribed to the highest rigidity of the polymer chain, which still carries relatively long alkoxy substituents that promote sufficient adhesion between the LCP and PBT matrix. When compared with the PBT fiber itself, the fibers obtained from the 5% TB-S6/PBT blends exhibited an improvement in tensile strength by 〉 25% and in tensile modulus by ∼ 200%.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352006
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 119
    Electronic Resource
    Electronic Resource
    Effect of die geometry on the structural development of a thermotropic liquid crystalline polymer in a thermoplastic elastomer matrix (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1621-1628 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This study investigates deformation of a thermotropic liquid crystalline polymer (TLCP) in different die geometries. Blends of aTLCP with a thermiplastic elastomer of EPDM were made in a twin-screw extruder. Morphological observation of the extruded blends demonstrates the complimentary effect of shear in the die exit on dispersed phase deformation and fibril formation. Shear strain can affect fibril formation for a relatively large dispersed phase in the region close to the die wall. However, the main role of shearing is in breaking up the larger particles and initial polydomain structure. A strong elongational deformation on the blended melt after the die exit is required, and fine microfibrils normally obnserved in in situ composites were not easily formed by shear deformation only in the die.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352008
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 120
    Electronic Resource
    Electronic Resource
    Rheological study on poly-D(-)(3-hydroxybutyrate) and its blends with poly(ethylene oxide) (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1636-1642 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Aspects of thermal, morphological, and rheological properties of biodegradable poly-D(-)(3-hydeoxybutyrate) (PHB) blended with poly(ethylene oxide) (PEO) have been studied. Thermal properties and morphology of the blends were examined by scanning electron microscopy and differential scanning calorimetry, respectively. A rotational theometer with parallel plate geometry was also adopted to investigate the rheological properties of these blends. In addition, dynamic ciscoelasticity was measured by a Rheovibron as functions of time and temperature. From these measurements, PHB and PEO were observed to be miscible in the melt state. In the case of the blend systen 80/20 PHB/PEO by weight, the vacant domains of the PHB were filled with PEO particles, and this morphological state enhanced the rheological properties. Furthermore, PHB and its blends were found to have high crystallinities, but to have unstable thermal behavior about Tm.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352010
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 121
    Electronic Resource
    Electronic Resource
    Morphology and dynamic mechanical properties of nylon 66/ poly(ether imide) blends (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1643-1651 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The morphology and dynamic mechanical properties of blends of poly(ether imide) (PEI) and nylon 66 over the full composition range have been invesigated. Torque changes during mixing were also measured. Lowertorque values than those calculated by the log-additivity rule were ontained, resulting from the slip at the interface due to low interaction between the componeents. The particle size of the dispersed phase and morphology of the blends were examined by scanning electron microscopy. The composition of each phase was calculated. The blends of PEI and nylon 66 showed phase-seoarated structures with small spherical domains of 0.3 ∼ 0.7 μm. The glass transition temperatures (Tgg) of the blends were shifted inward, compared with those of the homopolymers, which implied that the blends were partially imiscible over a range of compositions. Tg1, corresponding to nylon 66-rich phase. This indicated that the fraction of PEI mixed into nylon 66-rich phase increased with decreasing PEI content and that nylon 66 was rerely mixed into the PEI-rich phase. The effect of composition of the secondary relaxations was examined. Both Tβ, corresponding to the motion of amide groups in nylon 66. and Tγ′, corresponding to that of either groups in PEI, were shifted to higher temperature, probably because of the formation of intermolecular interactions between the components.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352011
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 122
    Electronic Resource
    Electronic Resource
    Determination of relaxation time spectra by analytical inversion using a linear viscoelastic model with fractional derivatives (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1661-1669 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Recently, Friedrich proposed an empirical model for linear viscoelastic fluids corresponding to a constitutive equation with fractional derivatives [Phil. Mag. Lett., 66, 287 (1992)]. For this model, the relaxation modulus, the dynamic moduli, the relaxation time spectrum, and other material functions have been explicitly calculated as a function of the few parameters that characterize a viscoelastic fluid within this model. By fitting this model to experimental data, the model parameters can be determined and other material functions, in particular the relaxation time spectrum, can be calculated immediately. This paper reports to what extent this method, which may be called analytical inversion, is appropriate for the determination of relaxation time spectra. For that pupose, the spectra of a number of very different polymeric materials are determined with this method. The spectra calculated in this way are compared with the spectra obtained by nonlinear regularization. It turns out that the empirical model describes the linear viscoelastic properties of a variety of different materials with high accuracy. Keeping in mind that the determination of the relaxation time spectrum requires the solution of an ill-posed problem, the agreement between the relaxation time spectra obtained by analytical inversion and by regularization is satisfactory for these materials.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352102
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 123
    Electronic Resource
    Electronic Resource
    Mixing and morphological transformations in the compounding process for polymer blends: The phase inversion mechanismPresented at 1991 ANTEC. Society of Plastics Engineers, May 5 - 9, 1991. montreal (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1688-1694 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This study reports on the progression of processes occurring in polymer blends during mixing. For the polymer pellet blends studied, an abrupt phase inversion was observed simultaneous with attainment of maximum torque in the batch mixer. A four-step phase inversion mechanism is described as predominant where dissipative mix-melting of the polymer system occurred in the mixing process.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 124
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 125
    Electronic Resource
    Electronic Resource
    Stress-Strain curves for solid polymers (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1725-1732 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In order to provide nw experimetnal facts required for constructing a nonlinear constitutive equationfor solid polymers, some tests wee conducted on amorphous pojymers of polycarbonate and poly(methyl methacrylate) and for a crystalline polymer of polyxymethylene under varous strain paths such as comprssion, torsion and combined tension-torsion. It is shown that (1) the stress-strain behavior for the strain paths without strain reversal is described well not only for amorphous polymers, but also for crystalline polymers by an overstess theory proposed by Krempl, and (2) at the strain paths wth stran reversal, the stress responses are considerably differetn from what is expected for the fstress responses of metals and their alloys.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352202
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 126
    Electronic Resource
    Electronic Resource
    The hybrid FEM/FDM computer model for analysis of themeteirng section of a single-screw extruder (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1748-1757 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A hybrid FEM/FEM computer model was employed n this studyfor simulating the non-newtonian, nonisothermal polymr melt fielt in the inetering section of a single-screw extruder. The pressure distribution in the screw surface was obtained by solving the generalized Reynolds equation. Instead of using the energy equation in Eulerian frame, a Lagrangian expression ws involved for stabilizing the numerical scheme. The temperature profiles wee obtained by finite difference discretizaton for the energy equation in such element. The screw surface with the screw channels and the flight lands could be modeled as a surface divided into small shell elements. To demonstrate aplicability, the results provided by the hybrid FEM/FDM were found to be similar to those of the 2D FDM for the trhermally developing flow, through Fenner's example. It can also ilustrate the leakage flow and the cross-channel effect in the screw pumping problem. The results from the Hybrid FEM/FDM revealed that if the clearance becomes too large, the volumetric flow rate would considerably decrease and the exist melt temperature would increase. In addtion, when the clearance is close to the normal design clearance, the leakage flow through the flight lands was found to be small. These computational results were observed to correlate with those of other experimental studies. Finally, the hybrid FEM/FDM approach can in principle be extended to the non-Newtonian, nonisothermal flow in a complex screw surface such as the barrier screw and the Maddock mixing head.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 127
    Electronic Resource
    Electronic Resource
    Low shear viscosity and crystallization in dilute solutions of polymers at high pressures: Falling body viscometry of high molecular weight polyethylene solutions (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1781-1784 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A specially designed falling body viscometer has been used to obtain low shear viscosities of dilute solutions of high molecular weight polyethylene in decalin and for detecting phase transitions at high pressures. The method provides valuable rheological data at pressures that correspond to those I lubrication and some extrusion processes. In addition, the method enables detection of phase transitions, such as crystallization, that result in detectable changes in rheology. The influence of pressure as high as 0.6 GPa ( ∼ 80.000 psi) is illustrated here through a study of crystallization, with verification from light scattering and calorimetry.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 128
    Electronic Resource
    Electronic Resource
    A simple model for heat transfer inside an extrusion die (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1713-1724 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A simple model based on the lubrication approximation has been developed to analyze heat transfer of power-law fluids inside an extrusion die. This model can effectively predict the influence of temperature variations and other production alterations on flow uniformity. The predictions of this model are compared with those based on three-dimensional finite element simulation, and the agreement is satisfactory. The optimal design concept can be incorporated into this model so that a specially designed choker bar can be inserted into the extrusion die to reduce flow nonuniformities. The shape of the choker bar is initially suggested by the lubrication model; minor corrections through the three-dimensional finite element simulation are then introduced so that a choker bar can be properly constructed to eliminate flow nonuniformities.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352108
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 129
    Electronic Resource
    Electronic Resource
    An algorithm for analysis of polymer filling of molds (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1758-1765 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A numerical implementation of the Volume of Fluid (VOF) free surface technique, applied to a filling process governed by a potential flow, is introduced. The implementation is based on a finite element control volume space discretization and uses an implicit time integration. This allows for the accurate tracking of the filling front using large simulation time steps in molds with complex geometries. The approach is validated on comparision with the analytical solution for filling a one-dimensional tube and with two-dimensional results obtained with previously-presented filling algorithms. Examples of the application of the approach in the analysis of structural resin transfer molding (SRTM) are presented. The capability of the method is demonstrated on predicting “race tracking” and “dry spotting” phenomena. The CPU requirement for a typical analysis is on the order of 1 to 20 s on pesonal computers.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 130
    Electronic Resource
    Electronic Resource
    A unified K-BKZ model for residual stress analysis of injection molded three-dimensional thin shapes (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1733-1747 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The flow-induced and thermally induced residual stresses during injection molding of a thin part with complex geometries are predicted. The injection molding precess was considered to consist of a filling and a post-filling stage (packing coupled with cooling). Additionally, the analysis were applied to successive stages of the process. The model takes into account the viscoelasticity of the molding polymer, which has been neglected in most previous works, because of the complexity of its inclusion. A unified K-BKZ viscoelastic constitutive model, capable of modeling both the fluid-rubbery state and the glass state of amorphous polymers, was employed for simulating this problem. For the flow-induced residual stress predictions of the filling stage, a quasi-steady state approximation was employed for each element of the part, for the calculation of stress profile and subsequent stress relaxation after cessation of flowf. Stress calculations were provided for the thermally induced residual stress predictions of the post-filling stage. These explicit calculations led to the results of pressure and temperature distributions of the part during the post-filling stage into the viscoelastic constitutive model. Additionally, the pressure and asymmetric temeprature profiles of the post-filling stage were based on finite element packing analysis coupled with a boundary element cooling analysis of the molding process. Finally, the total residual stress in the part was obtained via superposition of the flow-induced and thermally induced residual stresses. An example is provided to demonstrate the entire concept. The results indicate that thermally induced residual stress is higher than the flow-induced residual stress by one to two orders of magnitude.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352203
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 131
    Electronic Resource
    Electronic Resource
    Dynamics of liquid-liquid mixing: A 2-zone model (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1766-1780 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The development of multiphase liquid-liquid morphologies during mixing at small Reynolds numbers has been modeled. The mixing process is divided into (i) stretching of dispersed drops. (ii) breakup of the liquid threads formed, and (iii) coalescence of the final droplets upon collision. Rules and criteria of the distinct processes are presented and combined to a general 2-zone mixing model simplifying the flow field into a sequence of alternating “strong and weak zones.” In a “strong zone,” dispersed drops and threads are stretched unless their radius is too small; meanwhile, the stretching threads might break up into droplets. In the subsequent “weak zone,” the remaining threads may disintegrate while any drops present may coalesce. After passing a number of zones, stretching, breakup, and coalescence lead to a dynamic equilibrium that could be considered as the “final” morphology. Using the 2-zone mixing model, the influence of material parameters and processing conditions on the morphology has been studied. Interestingly, increasing either viscosity (dispersed or continuous phase) yields a finer morphology due to the delay of thread breakup, allowing for further stretching and suppression of coalescence.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352206
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 132
    Electronic Resource
    Electronic Resource
    Biopolyester melt behavior by torque rheometry (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1795-1806 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A torque rheometer method has been developed to evaluate the melt behavior of biopolyesters. The main features of this technique include: (i) a modified equipment configuration, so as to maintain the melt temperature within ± 1°C pf the set temperature after the first few minutes of polymer melting and thermal equilibration, and (ii) a kinetic equation that can be used to determine the melt behavior from the torque-time data. Applying this methology to a poly(3-hydroxybutyrate-co-3-hydroxyvalerte) copolymer shows that the degradation kinetics follow Arrhenius behavior with temperature, that the degradation rate increases with increasing hear, and that the activation energy for random chain scission is independent of shear rate. This effect of shear on the degradation process may be a result of viscous heating. The degradation rate is increased because of the increased internal energy of the polymer chains as a result of the mechanical deformation. There is no evidence of direct mechanical degradation. Last, the viscosity values obtained with the torque rheometer are consistent with those obtained by capillary rheometry.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352209
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 133
    Electronic Resource
    Electronic Resource
    A polytetrafluoroethylene filled ultra-high molecular weight polyethylene composite: Mechanical and wear property relationships (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1785-1794 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This research addresses the wear properties and processes of 10 vol% polytetrafluoroethylene (PTFE) filled ultra-high molecular weight polyethylene (UHMWPE) composites and their relationship to mechanical properties. The addition of the PTFE micropowder results in a slight increase in modulus and a significantly lower strain at break. This is due to a quasi-brittle failure mechanism. Crosslinking the UHMWPE reduces both the modulus and the ultimate properties. Polymer wear studies against SiC abrasive paper can be divided into initial and steady-state processes. The initial wear, polymer-SiC wear, is dominated by microcutting and the formation of a transfer film. A single-pass wear rate (R1) can be derived from a power-law description of the initial wear. The steady-state wear eventually achieved, called polymer-film wear, is dominated by sliding against a self-generated. A steady-state multiple-pass wear rate (Rx) can be derived from a linear description of steady-state wear. The relationships between the wear of UHMWPE and the wear of PTFE can be predicted through their ultimate and deformation properties and through an understanding of the wear mechanisms. These relationships cannot be used to relate composite and UHMWPE wear due to their different failure mechanisms. The lower Rx and coefficient of friction of the composite may be related to the PTFE flakes found on the worn and wearing surface. Crosslinking the UHMWPE yields little change in the worn and wearing surfaces and in Rx. The increase in R1 on addition of PTFE and decrease in R1 on crosslinking may be related to the respective increase and decrease in modulus.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352208
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 134
    Electronic Resource
    Electronic Resource
    Comparisons of experimental data to indices of adhesion derived from dielectric models (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1811-1817 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A perspective of adhesion is offered using average property indices such as dielectric constant, dipole moment, and thermal conductivity. These indices have been derived by comparisons of dielectric theories of adhesion and cohesion with comparisons to experimental data found in the literature. For example, it was found that adhesion generally increases with increased dielectric constant, or with the inverse of the thermal conductivity, for metal substrates. It was also found that ranges in the experimental data found were primarily caused by changes in surface roughness, which meant that interaction densities were not predictable.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352211
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 135
    Electronic Resource
    Electronic Resource
    Stretch and inflation of hyperelastic membranes as applied to blow moldiing (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1852-1863 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The free and confined inflation of isotropic homogeneour membranes of general shape are considered. The material is assumed to obey the Mooney-Rivin constitutive model, and the resulting partial differential equations, governing the deformation field, are solved using a Galerkin based finite-element procedure. The method is illustrated through examples of both free and conflined inflation, as well as simulationeus stretch and inflation. Measurements were carried out on the final thickness distributionof containers blow-molded inour laboratory. These containers typically cover a wide range of geometry adn size, including bottles with handles. Comparison between theory and experiment leads generally to good agreement, despite the limitation of the membrane hypothesis.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 136
    Electronic Resource
    Electronic Resource
    Extrude distortion in the capillary/slit extrusion of a molten polypropylene (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1864-1871 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Experiments were carried out in both sliding plate and capillary rheometers with a polypropylene resin to determine the conditions for the onset of slip, surface, and gross melt fracture. It was found that there was no distinction between surface and gross melt fracture, which is commonly observed in the case of polyethylenes. Furthermore, the flow curves determined by using capillaries having various diameters are diameter independent implying the absence of slip. However, experiments with slit dies having rough surfaces suggest wall slip. Further analysis has shown that the effect of viscous heating masks the detection of slip from the diameter-dependency of the flow curves. The effect of a thin layer of fluoropolymer (Teflon PA, DuPont) on the critical shear stress for the onset of wall slip and melt fracture, as well as on the relationship between the wall shlip and the shear stress, were also examined. It was found that the presence of such layers increases the slip velocity, while it decreases the critical shear stress for the onset of slip.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352305
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 137
    Electronic Resource
    Electronic Resource
    Ultrasonic behavior of polymer blends (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 79-91 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: During the last few years, improvements in control strategies became a necessity, with controls being targeted on material properties. The ever-increasing demand for polymer blends spells the need for in-line instrumentation capable of monitoring blend properties such as morphology. Since ultrasonics have proved to be sensitive to properties of multiphase materials, their performance for discriminating blend morphology was explored here. In-line and off-line (static, with no flow) ultrasonic measurements were made on different blends of polystyrene (PS), polyethylene (PE), and polypropylene (PP) for various viscosity ratios, and over the entire range of composition. Blends were compounded on a ZSK-30 Werner & Pfleiderer intermeshing co-rotating twin-screw extruder. In-line ultrasonic measurements were performed on both single-screw and twin-screw extruders. Ultrasonic properties (velocity and attenuation) were found to vary approximately linearly with composition. Mixing rules were evaluated for the description of ultrasonic behavior. For the attenuation measurements, the positive deviations from these rules were found significant. The additional attenuation was attributed to scattering generated by the presence of the minor phase inclusions.
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350111
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 138
    Electronic Resource
    Electronic Resource
    Rheo-Optical behavior of binary polymer blends: The effect of simple shear flow on phase behavior (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 92-99 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The phase behavior of polymer blends under simple shear flow has been studied using a custom-designed rheo-optical system consisting of a two-dimensional small-angle light scattering (SALS) device incorporated into a conventional rheometer. Two-dimensional SALS images were gathered for model polymer blend systems with different quiescent phase behavior: polystyrene/polyisobutylene (PS/PIB) that exhibits upper critical solution temperature phase behavior and polystyrene/poly(vinyl methyl ether) (PS/PVME) that shows lower critical solution temperature phase behavior. For the PS/PIB blend, shear-induced phase mixing occurred at a critical shear rate. Below that critical shear rate, the dispersed phase was highly elongated parallel to the flow direction. For PS/PVME blends, a streak scattering pattern was observed even though the sample became optically clear after shearing. We observed, apparently for the first time, the development of a bright-streak pattern from a transient dark-streak pattern for a polymer blend system under shear. Rheo-microscopy studies revealed an intriguing wave pattern that developed coincident with the observation of a streak pattern by SALS. The relationship between the two phenomena has not yet been established.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350112
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 139
    Electronic Resource
    Electronic Resource
    Milligrams to kilograms: An evaluation of mixers for reactive polymer blendingPresented in part at: ACS Annual Meeting 1993 Chicago. Presented at: Polyblends '93 Conference 1993 Montreal. (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 100-114 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The dispersions of both reactive and nonreactive polymer-polymer blend systems achieved in three different mixers are compared. The dispersions are prepared using an industrial scale twin-screw extruder, a laboratory internal mixer, and a miniature cup and rotor mixer. The morphology development in the three mixers is remarkably similar: The dispersed phase is stretched into sheets and ribbons; these sheets and ribbons then break into cylinders, which subsequently break into droplets via Rayleigh-type instabilities. Drop size distributions can be accurately predicted if we know the size of cylinders formed in the high shear fields of the mixer. There is a significant effect of quenching time on blend morphology - i.e, to properly evaluate mixing, blends must be quenched extremely quickly (well within a minute). Otherwise, we need to consider the morphology development during the quenching time, which may not be relevant to the mixing. There is a uniform shear stress in the miniature mixer, unlike the other mixers, which have varying stress levels. It is shown that a high stress level followed by a lower stress level is required in polymer blending to achieve efficient mixing. In the high stress level, the dispersed phase is stretched into extended shapes, which undergo instabilities and break up upon entering the low stress level. In the miniature mixer, the dispersed phase sees only one stress level, and thus very extended shapes persist at the end of mixing. The final dispersions in the twinscrew extruder and internal mixer at matched maximum shear rates are almost identical. For similar shear rates in the miniature mixer, the final dispersion of reactive blends is comparable to the other mixers. However, the miniature mixer does a poor job in dispersing high viscosity uncompatibilized blends, and the mixing conditions must be altered to obtain efficient mixing.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350113
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 140
    Electronic Resource
    Electronic Resource
    Compatibilized linear low-density polyethylene/isotactic polypropylene blends studied by positron annihilation lifetime spectroscopy (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 28-33 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Positron annihilation lifetime spectroscopy (PALS), capable of probing free volume, is used to study the effect of compatibilizer concentration, compatibilizer type, and the effect of blend processing on the morphology and properties of an immiscible linear low-density polyethylene/polypropylene system. It is proposed that improvement of fracture toughness due to compatibilization can be attributed to the packing (and bonding) at interfaces. Improved interfacial packing and bonding result in lower free volume concentration than expected from component additivity, with a concomitant increase in plastic deformation on impact.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 141
    Electronic Resource
    Electronic Resource
    Time-resolved small-angle light scattering for the study of phase separation kinetics in bisphenol-a polycarbonate/poly(methy methacrylate) blends (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 34-40 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An automated, solid-state small-angle light scattering apparatus has been constructed for the investigation of polymers; the main features of this system are a bidimensional CCD (charge coupled device) detector with 12-bit resolution and custom-made, user-friendly software for the acquisition and treatment of the scattering data. The miscibility and phase separation kinetics of several bisphenol-A polycarbonate/poly(methyl methacrylate) blends have been investigated using this apparatus. It was found that the rate of phase separation can be altered significantly by replacing part of the polydisperse poly(methyl methacrylate) (PMMA) in the blends by monodisperse PMMA.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350106
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 142
    Electronic Resource
    Electronic Resource
    The development of laminar morphology during extrusion of polymer blends (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 41-51 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Studies of the microstructure and permeability of extruded ribbons of polypropylene (PP)/ethylene vinyl alcohol copolymer (EVOH) and polyethylene (PE)/polyamide-6 (PA-6) blends have shown that it is possible to control the flow-induced morphology to generate discontinuous overlapping platelets of EVOH or PA-6 dispersed phase in a PP or HDPE matrix phase. The effects of the following factors on morphology development and blend properties were considered: blending sequence, melt temperature, composition, compatibilizer level, die design, screw type, and cooling conditions. The impact properties and interfacial adhesion of laminar blends of PP and EVOH were improved without diminishing the barrier properties. The oxygen and toluene permeability of extruded samples with EVOH content of 25 vol% resembled values obtained with multilayer systems. Processing conditions had a major influence on the morphology of blends of high density polyethylene and polyamide-6 (HDPE/PA-6), and, under special processing conditions, laminar morphology was obtained in this system. The toluene permeability of extruded ribbons of HDPE/PA-6 blends was in the range obtained with multilayer systems.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 143
    Electronic Resource
    Electronic Resource
    Some relationships for the orientational drawing of polymersPart of the experimental data in this article was presented at the 4Th Rolduc Polymer Meeting, April 1989, Kerkrade, The Netherlands. (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 173-179 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The orientational drawing of films from different thermoplastics has been studied. The value of the activation energy of drawing in the regions of forced elasticity (necking), high elasticity, and viscous flow (ΔE1, ΔE2, ΔE3) has been found to vary directly with the activation energy for viscous flow of the melt (ΔEη). Here ΔE1 〈 ΔE2 〈 ΔE3 = ΔEη. Thus Δ Eη characterizes the potential of thermoplastics for orientational drawing under different deformation conditions, since it reflects simultaneously both the intermolecular interaction level and chain flexibility. For maximum chain orientation, the calculated values for the change in the entropy are close to that of the entropy change during crystallization (melting) of the same polymer. The deformation of polymer may be described as a deformation of an entanglement network from the standpoint of classic elasticity theory. Some parameters for an entanglement network were calculated from the results of the drawing experiments. The density of the entanglement network (DEN) depend on the polymer composition: For flexible-chain polymers the DEN is less, for rigid-chain polymers (with coiled chains) it is higher. The DEN affects the maximum (prebreak) drawing ratio: The greater the DEN, the smaller the ratio to which a film can be drawn. At high orientation, the tensile strength of different polymer films tend to be similar, if drawing is not accompanied by crazing.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350209
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 144
    Electronic Resource
    Electronic Resource
    Block copolyetherester. Part 3: Preparation of block copolyetheresters by a terephthalic acid process in the presence of salts (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 190-194 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The block copolyetheresters with hard segments of poly(butylene terephthalate) and soft segments of poly(tetramethylene ether) were prepared by a terephthalic acid (TPA) process in the presence of some salts. The preparations of a block copolyetherester under various conditions were first studied in a 1 L stainless steel reactor to find the best method. Then, the preparations of four block copolyetheresters were run in a pilot plant comprising a 200 L polyesterification reactor and a 200 L polymerization reactor under the suitable condition. The presence of some salts reduced the formation of tetrahydrofuran (THF), and also reduced the total reaction time in the pilot plant. The thermal properties and various mechanical properties of the block copolytheresters prepared by the pilot plant were investigated to evaluate the feasibility of this method.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350212
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 145
    Electronic Resource
    Electronic Resource
    Review of stabilization of polyolefin insulated conductors. Part I: Theory and factors affecting stability (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 211-217 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The understanding of the failure mechanism causing cracks in insulated telephone wire is critical to developing a solution to the problem. This paper reviews the antioxidant and metal deactivator theory as it applies to polyolefins and reviews the factors, both internal to the polymer and external which affect stability. Degradation theory in vacuum and air is reviewed. Primary and secondary antioxidants are discussed as are multifunctional metal deactivator/antioxidant molecules. The internal factors affecting thermal stability which are discussed include: polymer synthesis process, molecular weight, molecular weight distribution, crystallinity, phase state, orientation, amount of antioxidant, amount of metal deactivator, and amount of blowing agent. The external factors affecting long term life are: temperature, oxygen, ozone, stress, filling compound, and presence of copper.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350215
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 146
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350301
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 147
    Electronic Resource
    Electronic Resource
    Screw optimization of a co-rotating twin-screw extruder for a binary immiscible blend (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 225-232 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of the screw configuration of a closely intermeshing co-rotating twin-screw extruder on residence time and mixing efficiency was studied for an uncompatibilized immiscible PA6/PP (80:20) bend. Alternative screw configurations were investigated systematically. The residence time distribution (RTD) was found to be a poor indicator of the total mixing efficiency, whereas the mixing intensity function yielded considerably better information. High shear stress, sufficient residence time, and high fill ratio in the melting section of the screw were the most important factors in achieving good dispersion of the minor phase. The evolution of morphology along the screw axis depended strongly on the screw configuration. The downstream flow characteristics after the screw end determined the final morphology of the blend.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350302
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 148
    Electronic Resource
    Electronic Resource
    A preliminary investigation of flash formation during injection molding of polyphenylene sulfide and liquid crystalline polymer blends (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 240-246 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Flashing in pure polyphenylene sulfide (PPS) and a blend containing PPS and liquid crystalline polymer (LCP) during injection molding was investigated by differential scanning calorimetry and scanning electron microscopy. The shape of the flash was observed by use of a projector. Flashing was detected in pure PPS and 90/10 PPS/LCP blend but was not found in other compositions, including pure LCP. The DSC thermograms of the flash revealed both exothermic and endothermic peaks at around 120° and 285°C. The first peak, known as crystallization temperature on heating, occurred as a result of early crystallization of PPS. The observed double peaks indicated that the degree of crystallinity was lower in the flash than in the molded part. The morphological studies revealed the presence of LCP fibrils in the skin region and droplets in the core region of 90/10 PPS blend. The absence of flash was attributed to the diameters of the fibrils and droplets, which were found to increase with increasing LCP component.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 149
    Electronic Resource
    Electronic Resource
    Nonisothermal bubble growth in polymeric foams (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 252-260 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The dynamics of a large number of bubbles separated by distances of the order of their radii in highly viscous fluids with specific application to foams is investigated. The growth of bubbles is due to diffusion of gas from the fluid and the momentum transfer between the fluid and the bubbles. Equations governing the growth of a single bubble in a shell of fluid containing limited dissolved agas are coupled with the transport equations for the fluid under non-isothermal conditions. The resulting set of equations are solved numerically for a system of bubbles growing along the axial direction in a mold. The results predict a bubble size distribution along the axial direction with large bubbles close to the melt front and smaller bubbles close to the gate, which results in a density distribution in the molded article. Experimental studies on structural foam under nonisothermal conditions are performed. The transient bulk foam density is measured by monitoring the melt front as the foam expands. The predicted values of the foam density are compared with the experimental results and the sources of error are discussed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 150
    Electronic Resource
    Electronic Resource
    Numerical simulation of fluid flow and heat transfer in a single-screw extruder with different dies (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 261-273 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In a plasticating screw extruder, a polymer melt forms in the melting zone of the extruder. Pressurization of the molten polymer takes place in the melting and the metering sections so that the melt can flow through the restricted passage of the die and assume a desired shape. In a melt fed extruder, the throughput is governed by the pressure rise over the entire length of the extruder. The pressure developed in the screw channel may also be employed in rapid filling of molds, such as those in injection molding. When the geometry of the screw, the barrel temperature, and the die are selected, a unique set of operating parameters arise for a particular flow rate or screw speed. In the present study, numerical and analytical methods are used to calculate the transport in the extruder and the pressure drop in the die. An iterative numerical method based on solving the equations of motion and energy in the screw channel and a correction scheme to couple the die with the screw channel is discussed. The numerical algorithm is capable of handling an arbitrary variation of the viscosity of the polymeric fluid with the shear rate and temperature. The results obtained by simulating the fluid flow in the screw channel are compared with available numerical and experimental results in the literature, indicating good agreement. The performance characteristics of the extruder, for chosen thermal boundary conditions and screw geometry, are presented for different die geometries and different fluids. The important considerations that arise in the numerical simulation of the extrusion process are also discussed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350307
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 151
    Electronic Resource
    Electronic Resource
    Preface (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 289-290 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350402
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 152
    Electronic Resource
    Electronic Resource
    On the phenomenology of yield in bisphenol-a polycarbonate (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 291-303 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The phenomenology of yield in bisphenol-A polycarbonate is explored through tensile tests on thin rectangular specimens and through pressure-induced bulging of thin, clamped circular disks. In a tensile test, while the nominal critical stress at which yield initiates and the nominal draw stress at which a stable neck propagates along a specimen depend on the temperature and the strain rate, the ratio of the draw stress to the critical stress is shown to be approximately 0.75 over a temperature range of 22 to 65°C and strain-rates in the range of 10-4 to 100 s-1. Specimens subjected to constant tensile loads between the draw and critical stresses are shown first to creep till stretches on the order of 1.06 are attained and then are shown to undergo stable necking. Tensile tests on thin, wide rectangular specimens show that yielding initiates through shear bands that broaden and intersect to generate necks, which subsequently propagate along the specimen. In pressure-induced bulging of clamped disks, biaxial stretching progresses monotonically under increasing pressures; strain localization does occur near the outer edges of the specimens, however. Heating of a specimen with a substantial stably necked region shows that the temperature-induced recovery of the specimen from its deformed state begins well below the transition temperature Tg of the material, although most of the recovery occurs at Tg.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 153
    Electronic Resource
    Electronic Resource
    Plastic behavior and deformation textures of poly(etherether ketone) under uniaxial tension and simple shear (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 317-330 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Samples of poly(etherether ketone) (PEEK) were subjected to large plastic deformations under uniaxial tension and simple shear by means of a new video-controlled testing method at constant true strain rate. The “equivalent” stress-strain curves obtained under the two loading modes are close at the yield point, but diverge drastically at large strains, with a rapidly increasing hardening in tension and a moderate hardening under simple shear. X-ray diffraction goniometry shows that these contrasting behaviors are associated with the different textures developed in the crystallite orientations. Under tension, the PEEK lamellae are progressively tilted in such a way that the chain axis becomes oriented parallel to the tensile axis; in the other mode, the final chain orientation is near to the shear axis. DSC analyses of deformed samples in both modes are carried out. The results show that the tension loading induces a fragmentation of the thin lamellae, while the shear mode generates less fragmentation. A quantitative model is presented that involves a composite approach: (i) the viscoplastic deformation of the crystalline lamellae, which is controlled by chain slip and transverse slip systems on planes parallel to the c axis, and (ii) the hyperelastic deformation of the amorphous phase, which depends on the affine unfolding of statistically distributed subchains. A discussion of the influence of the CRSS values on the stress-strain curves and textures is developed by means of this model.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350406
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 154
    Electronic Resource
    Electronic Resource
    Mechanical response of beams of a nonlinear viscoelastic material (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 345-350 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A constitutive equation for nonlinear viscoelasticity is used to model the mechanical response of solid polymers such as polycarbonate. The nonlinearity arises from a reduced time which causes stress relaxation to accelerate with increasing strain. The constitutive equation can account for the occurrence of yield in a homogeneous uniaxial constant strain rate test. The constitutive equation is used in a study of the pure bending of beams. It is assumed that the classical assumption of beam theory is valid, i.e., plane sections remains plane. At each fixed time, the strains vary linearly through the depth of the beam. At a fixed material element the strain varies in time with the curvature. This spatial variation of the strains combined with the nonlinear dependence of the reduced time on strain leads to a significantly different response from that given by traditional beam theory. The implications of this for the bending moment history, stress distributions, and other factors that relate to beam design are discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350408
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 155
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350501
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 156
    Electronic Resource
    Electronic Resource
    Preface (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 385-386 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350502
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 157
    Electronic Resource
    Electronic Resource
    The evolution of material properties during physical aging (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 403-410 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Aging experiments using the NIST (National Institute of Standards and Technology) torsional dilatometer have been performed in which the temperature of an isothermally equilibrated epoxy glass was abruptly changed to a new temperature T0 and the evolution of the volume and torsional relaxation responses recorded. The results of down-jump and up-jump experiments were found to differ dramatically. Not only is the normal asymmetry of volume approach to equilibrium found, but the mechanical responses are found to evolve differently from the volume response, contrary to simple free volume models of the physical aging process. It is found that the torsional modulus changes with increasing time after the T-jump. In the case of the down-jump the evolution of the modulus ceases prior to that of the volume of the sample. In the up-jump experiment, the contrary is true, viz., the modulus continues to evolve after the volume has attained its equilibrium value. The implications of this for the description of material behavior are discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350505
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 158
    Electronic Resource
    Electronic Resource
    An investigation into the three-dimensional stress-birefringence-strain relationship in elastomers (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 395-402 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The statistical theory of the birefringence of an individual non-Gaussian elastomer chain is used together with a chain network description of rubber elasticity to develop a relationship among the strain, birefringence, and stress in elastomers, valid for large deformations under generalized strain states. The result is a fully three-dimensional internal variable based constitutive model of rubber elasticity in which measurement of the elastomeric birefringence during straining in one deformation state characterizes the optically anisotropic response of the elastomer. Simultaneous measurement of the stress vs. strain response provides the rubbery modulus and limiting network extensibility properties needed to completely characterize the mechanical anisotropy of the material. Once characterized using the single, large deformation experiment, the birefringence and stress responses of the elastomer in other deformation states may then be predicted without adjusting any model parameters. The theory is compared to experimental studies from the literature of large strain deformations of elastomers in uniaxial tension and compression for which the exhibited birefringence and stress responses of deforming elastomers have been simultaneously recorded.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350504
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 159
    Electronic Resource
    Electronic Resource
    A constitutive theory for rigid polyurethane foam (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 387-394 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Rigid, closed-cell, polyurethane foam consists of interconnected polyurethane plates that form cells. When this foam is compressed, it exhibits an initial elastic regime, which is followed by a plateau regime in which the load required to compress the foam remains nearly constant. In the plateau regime, cell walls are damaged and large permanent volume changes are generated. As additional load is applied, cell walls are compressed against neighboring cell walls, and the stiffness of the foam increases and approaches a value equal to that of solid poyurethane. When the foam is loaded in tension, the cell walls are damaged and the foam fractures. A constitutive theory for rigid polyurethane foam has been developed. This theory is based on a decomposition of the foam in two parts: a skeleton and a nonlinear elastic continuum in parallel. The skeleton accounts for the foam behavior in the elastic and plateau regimes and is described using a coupled plasticity with continuum damage theory. The nonlinear elastic continuum accounts for the lock-up of the foam due to internal gas pressure and cell wall interactions. This new constitutive theory has been implemented in both static and dynamic finite element codes. Numerical simulations performed using the new constitutive theory are presented.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350503
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 160
    Electronic Resource
    Electronic Resource
    Measurement of the J integral in polycarbonate using the method of caustics (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 426-431 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The nonlinear fracture behavior of polycarbonate is investigated. The feasibility of measurement of the J integral through the optical method of reflected caustics is demonstrated. Significant increase in the crack growth resistance during small amounts of crack extension is observed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350508
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 161
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350601
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 162
    Electronic Resource
    Electronic Resource
    Effect of the pressure drop rate on cell nucleation in continuous processing of microcellular polymers (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 432-440 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Microllular plastics are cellular polymers characterized by cell densities greater than 109 cells/cm3 and cells smaller than 10 μm. One of the critical steps in the continuous production of microcellular plastics is the promotion of high cell nucleation rates in a flowing polymer matrix. These high nucleation rates can be achieved by first forming a polymer/gas solution followed by rapidly decreasing the solubility of gas in the polymer. Since, in the processing range of interest, the gas solubility in the polymer decreases as the pressure decreases, a rapid pressure drop element, consisting of a nozzle, has been employed as a continuous microcellular nucleation device. In this paper, the effects of the pressure drop rate on the nucleation of cells and the cell density are discussed. The experimental results indicate that both the magnitude and the cell density are discussed. The experimental results indicate that both the magnitude and the rate of pressure drop play a strong role in microcellular processing. The pressure phenomenon affects the thermodynamic instability induced in the polymer/gas solution and the competition between cell nucleation and growth.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350509
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 163
    Electronic Resource
    Electronic Resource
    Effects of variable viscosity on the steady melting of thermoplastics during spin welding (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 441-459 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The steady melting of several amorphous and semicrystalline polymers during spin welding is analyzed by solving a simplified set of momentum and energy balance equations, assuming a shear-rate and temperature-dependent viscosity. A numerical model is developed for predicting the flow field and the temperature distribution in the molten film. It is shown that the steady melting rate of the thermoplastic solid is affected by the variable viscosity, by the pressure applied on the parts to be joined, and by a balance between the viscous heat generation in the melt and the convection of colder material into the molten film. The convection of heat in the outflow direction is shown to have a much smaller effect on the melting process.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350510
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 164
    Electronic Resource
    Electronic Resource
    Enhanced polycarbonate toughness. II: Mechanisms (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 477-482 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Glassy shell-rubbery core polymer particles, 0.1 to 0.2 μm in diameter, increase the plane strain JIC values of 3.175 mm thick polycarbonate from 3.05 kJ/m2 (no particles) to 9.5 kJ/m2 (7.5 phr particles) at 23°C. Some modest decreases in these values are caused by tests at -20°C in samples 9.525 and 3.175 mm thick. If only the particle concentration is varied, JIC increases monotonically to 7.5 phr (by wt), then levels off or decreases slightly at 10.0 phr. The total volume of 1 to 2 μm diameter cavities formed in the matrix by the apparently unbonded particles behaves similarly; cavity volume and JIC are directly related. With increasing particle concentration the tensile modulus is unchanged, the yield stress and strain decrease modestly, the strain at fracture decreases appreciably, and the heat recoverable orientation in the fractured samples decreases. Few cavities are formed. The particles reduce the extent of shear deformation in the tensile samples.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350604
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 165
    Electronic Resource
    Electronic Resource
    A process model for nonisothermal photopolymerization with a laser light source. I: Basic model development (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 483-492 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A mathematical model for a laser-induced photopolymerization process has been developed. This model simulates important aspects of stereolithography, a rapid prototyping process used for the production of three-dimensional plastic parts. The model consists of a set of coupled partial differential equations and considers irradiation, chemical reaction, and heat transfer in a small zone of material exposed to a stationary UV laser source. Numerical techniques are used for an approximate solution of the model equations, and the output includes spatial and temporal variations in the conversion of monomer to polymer, depletion of photoinitiator, and local variations of temperature in and around the region contacted by the laser light. Maximum conversions of approximately 60% and peak temperature rises of approximately 35° C were calculated for the cylindrical exposed region. Results have provided insights concerning laser dwell time, depth penetration, and the uniformity of polymer formed during the stereolithography process.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350605
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 166
    Electronic Resource
    Electronic Resource
    The relationship between structure and deformation behavior of sulfone polymers (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 499-505 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The deformation of three types of sulfone polymers - polysulfone (PSF), poly(ether sulfone) (PESF), and polyarylsulfone (PASF) - was performed with a mechanical testing system (MTS). The result and samples were studied using a transmission electron microscope (TEM), a dynamic mechanical analyzer (DMA), and a dielectric thermal analyzer (DETA). Stripes on TEM micrographs for small deformations increase with the fracture toughness (GIc). The activation energy (Ea) of the α-transition was determined from DETA. The results show that both Ea and TEM micrographs can be used to qualitatively estimate the order of GIc of sulfone polymers. An energy model was proposed to explain this phenomenon.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350607
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 167
    Electronic Resource
    Electronic Resource
    Low temperature melting behavior of CO2 crystallized modified PETs (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 506-512 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Differential scanning calorimetry (DSC) analysis has been performed on modified and commericial amorphous samples of poly(ethylene terephthalate) (PET) crystallized by high pressure carbon dioxide (CO2). Two endothermic peaks are present in the DSC scans of all the carbon dioxide-treated samples. A qualitatively analogous behavior has been detected in the case of amorphous samples heat treated at temperatures slightly exceeding the glass transition temperature of virgin material. Wide angle X-ray scattering analysis has confirmed the structural analogies between samples CO2 crystallized at 50°C and thermally crystallized slightly above Tg. A differential scanning calorimeter capable of working at high pressure of CO2 has been adopted in order to examine the effect of carbon dioxide on the crystallization temperature range.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350608
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 168
    Electronic Resource
    Electronic Resource
    Correlations between relaxation time spectrum and melt spinning behavior of polypropylene. II: Melt spinning simulation from relaxation time spectrum (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 518-527 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Using an integral nonlinear constitutive equation including the Log-Normal relaxation spectrum, the fiber-spinning behavior of commercial polypropylenes is studied. The relaxation spectrum is strongly related to the molecular weight distribution. Moreover, by means of a finite element analysis, simulated stress and velocity profiles are obtained either in isothermal or nonisothermal cases. In the isothermal case, broadening the relaxation spectrum leads to more pronounced curvature of the velocity profile. In the nonisothermal case, the critical draw ratio is sensitive to the mean relaxation time which depends on both average molecular weight and distribution breadth. It is shown that increasing the average relaxation time leads to a less rapid growth of the velocity. Furthermore, this effect is less pronounced when the relaxation spectrum is wider.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350610
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 169
    Electronic Resource
    Electronic Resource
    A process model for nonisothermal photopolymerization with a laser light source. II: Behavior in the vicinity of a moving exposed region (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 493-498 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A mathematical process model that stimulates important aspects of stereolithography, a rapid prototyping technique used for the production of three-dimensional plastic parts, has been developed. The model consists of a set of coupled partial differential equations and considers irradiation, chemical reaction, and heat transfer in a vat of photomonomer exposed to a moving UV laser source. Laser motion occurs in a straight line (vector path), and the model thus simulates the production of a single strand of plastic. Numerical techniques are used for approximate solution of the model equations, and output includes spatial and temporal variations in conversion of monomer to polymer, depletion of photoinitiator, and variations of temperature along the line of exposed material. The formation of a temperature wave that moves along the line of plastic is observed, together with the fact that the leading edge of the wave is steeper than the trailing edge, i.e., the material heats considerably faster than it cools. The maximum temperature of the wave reaches a pseudo-steady state after a short time. The results have provided useful information concerning the temperature at which the majority of the polymerization occurs; provided information on overall transient temperature behavior; allowed computer prediction of stereolithography working curves (cure depth and cure width vs. laser scan rate); and afforded a means for evaluating the amount of reaction that occurs in the dark period after light exposure.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350606
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 170
    Electronic Resource
    Electronic Resource
    Correlations between relaxation time spectrum and melt spinning behavior of polypropylene. 1: Calculation of the relaxation spectrum as a log-normal distribution and influence of the molecular parameters (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 513-517 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The linear viscoelastic behavior of commercial broad-distribution polypropylenes is studied. The samples underwent different controlled peroxide degradation rates, so they exhibit different molecular distributions. The relaxation spectrum is obtained by assuming that it takes the shape of a Log-Normal distribution. It is in agreement with the linear viscoelasticity theory by providing limiting values, contrary to other models. Moreover, the ratio τw/τn which takes place in this law is very useful to distinguish the synthesis differences of the samples when the Melt Flow Index alone cannot.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350609
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 171
    Electronic Resource
    Electronic Resource
    A study of creep and creep rupture of polycarbonate (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 546-554 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The creep characteristics of polycarbonate at elevated temperatures are investigated. The onset of glass transition temperature of polycarbonate is determined. An Arrhenius type relationship is used to describe the creep process and the concept of property retention index as applied to creep is discussed. An attempt is made to construct the master rupture curves for polycarbonate. The onset of glass transition temperature of polycarbonate was placed at around 110°C. It is concluded that the Arrhenius theory and the concept of property retention index are extremely useful in the construction of master rupture curves and that they require further investigation.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350613
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 172
    Electronic Resource
    Electronic Resource
    Morphology and mechanical properties of liquid crystalline copolyester and poly(ethylene 2,6-naphthalate) blends (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 538-545 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Blends of poly(ethylene 2,6-naphthalate) (PEN) and a liquid crystalline copolyester (LCP), poly(benzoate-naphthoate), were prepared in a twin-screw extruder. Specimens for mechanical testing were prepared by injection molding. The morphology and mechanical properties were investigated by scanning electron microscopy (SEM) and an Instron tensile tester. SEM studies revealed that finely dispersed spherical domains of the liquid crystalline polymer (LCP) were formed in the PEN matrix, and the inclusions were deformed into fibrils from the spherical droplets with increasing LCP content. The morphology of the blends was found to be affected by their composition and a distinct skin-core morphology was found to develop in the injection molded samples of these blends. Mechanical properties were improved with increasing LCP content, and synergistic effects have been observed at 70 wt% LCP content whereas the elongation at break was found to be reduced drastically above 10 wt% of LCP content. This is a characteristic typical of chopped-fiber-filled composites. The improvement in mechanical properties is likely due to the reinforcement of the PEN matrix by the fibrous LCP phase as observed by scanning electron microscopy. The tensile and modulus mechanical behavior of the LCP/PEN blends was very similar to those of the polymeric composite, and the tensile strength and flexural modulus of the LCP/PEN 70/30 blend were two times the value of PEN homopolymer and exceeded those of pure LCP, suggesting LCP acts as a reinforcing agent in the blends.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350612
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 173
    Electronic Resource
    Electronic Resource
    Coefficients of dynamic friction as a function of temperature, pressure, and velocity for several polyethylene resins (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 557-563 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The coefficient of dynamic friction is often the controlling factor for solids conveying, pressure generation, and thermal decomposition of a resin in the feed section of a single-screw plasticating extruder. The coefficients of friction are, however, very poorly understood, and the interpretation of the measurements are complicated by the dissipation of frictional energy at the sliding interface. A new instrument was recently built to help understand dynamic friction, and a numerical technique was developed to estimate the interface temperture. Coefficients of dynamic friction for several polyethylene resins are presented in this paper as a function of the surface temperature, pressure, and velocity. The relationship of the data with respect to the extrusion process is discussed.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350702
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 174
    Electronic Resource
    Electronic Resource
    A flow model for non-newtonian liquids inside a slot die (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 577-586 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A one-dimensional flow model for non-Newtonian liquids inside a dual-cavity slot die is presented. The model is capable of analyzing slot dies of any cavity shape, cavity taper, slot-length variations, and slot-gap variations. The proposed model incorporates a truncated-power-law model for the viscosity of non-Newtonian liquids. According to flow models with power-law approximation for liquid viscosity, the distribution of non-Newtonian liquid through a slot die depends on the slot Reynolds number only. With our model, we find that the zero shear viscosity and the relaxation time of a non-Newtonian liquid have large effects on its distribution. For non-Newtonian liquids which are expected to experience shear-thinning over portion of a slot die, it is concluded that a flow model with a truncated-power-law approximation for liquid viscosity be used to predict the liquid distribution from the die.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350704
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 175
    Electronic Resource
    Electronic Resource
    Residence time distribution in non-intermeshing counter-rotating twin-screw extruders (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 598-603 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This paper deals with the residence time distribution (RTD) in a non-intermeshing counter rotating twin screw extruder.The RTDs were measured in three vent zones of the extruder sparately, and in the adjacent zones combined, using a soluble dye as the tracer. Assuming that the RTDs in the adjacent zones are independent of each other, the overall RTD was also calculated using a previously developed statistical theory. The theory has also confirmed the consistency of the present measurements.A predictive RTD model for the non-intermeshing twin screw extruder, based on the flow analysis of the individual screw zones and their statistical superposition, was also developed. The predictions are in good agreement with experiment.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350706
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 176
    Electronic Resource
    Electronic Resource
    The flow-induced phase morphology of fluoroelastomer and polycarbonate blends during extrusion (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 619-636 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The flow-induced phase morphological development under different extrusion conditions was studied in terms of the rheological property and interfacial tension of various elastomers and thermoplstics. The interfacial tension for elastomers and thermoplastics was investigated by using a breaking thread method (1-4). We found that the method is suitable for measuring interfacial tension without degradation. The droplet-fibrillation transition phenomenon was observed in various extrudates of fluoroelastomer/polycarbonate blends. The criteria for the flow-induced morphology, in particular the droplet-fibrillation transition, are critically discussed in this paper.
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350708
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 177
    Electronic Resource
    Electronic Resource
    The conducting behavior and stability of conducting polymer composites (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 637-641 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Results of measurements of the electrical conductivity of low density polyethylene/polypyrrole and polystyrene/polypyrrole composites are reported. It is observed that the electrical conductivity of the composite vs. concentration follows the power law predicted by the percolation theory. The manufacturing process influences the homogeneity of the composite at microscopic scale and thus the percolation threshold. Annealing studies show that the stability of the electrical conductivity of the composite is related to the thermal expansion of the polymers and the relaxation of the polymer chains. The decrease of the electrical conductivity of the composite is attributed to the interruption of the percolation path.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350802
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 178
    Electronic Resource
    Electronic Resource
    The effect of a partly hydrolyzed styrene-tert-butyl acrylate diblock copolymer on the properties of poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and polyamide-6 (PA) blends (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 648-657 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The compatibilizing effect of a polystyrene-hydrolyzed poly(t-butyl acrylate) diblock copolymer (SBAH) on the phase structure, rheological properties, and mechanical properties of immiscible poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and polyamide-6 (PA) blends was investigated. The SBAH was prepared by sequential anionic polymerization of styrene and t-butyl acrylate, followed by acid-catalyzed hydrolysis of t-butyl acrylate block. Scanning electron micrographs show that the blends exhibit a more regular and finer dispersion when the SBAH of 47% hydrolyzed t-butyl acrylate block is added. By addition of small amount of the block copolymer, the blends show non-Newtonian power-law behavior, and the contribution of storage modulus (G′) to the total response increases. Solubility tests support the formation of graft copolymer by chemical reaction between amine groups of the PA and carboxyl groups of the SBAH. Both modulus and strength are improved about 20% with addition of the 3 wt% SBAH, while the elongation at break decreases notably; thus, the blends fail in a brittle manner.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350804
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 179
    Electronic Resource
    Electronic Resource
    A study on interfacial adhesion of poly(vinylidene fluoride) with substrates in a multilayer structure (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 666-672 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The peel force of a PVDF/3-APS/Si joint and a PVDF/3-APS/Al joint can reach the same level by treating the Si substrate with ≥ 0.3% 3-aminopropyltriethoxy silane (3-APS) solution and treating the aluminum substrate with NH3 solution (pH 10.5) first and then with ≥ 3% 3-APS solution. Scanning electron micrographs show that the interfacial adhesion mechanisms of PVDF/3-APS/Si joints and PVDF/3-APS/Al joints are different. In the peel test, the PVDF [poly(vinylidene fluoride)] break surfaces from PVDF/3-APS/Si joints reveal striations on the surface and less plastic deformation. The significant plastic deformation of the PVDF at the break surface may result from the deeper interpenetration of 3-APS with PVDF in the PVDF/3-APS/Al joint than in the PVDF/3-APS/Si joint. The peel force of PVDF film/substrate joint depends on many factors: film thickness, peel rate, concentration of coupling agent, the treatment time of the coupling agent on the substrate, and the substrate pretreatment.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 180
    Electronic Resource
    Electronic Resource
    Morphologies of mechanically mixed amorphous blends before and after annealing (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 693-702 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The morphologies of amorphous polymer blends produced by extrusion were investigated by transmission electron microscopy. Polymers with similar viscosities, i.e. poly(methyl methacrylate) (PMMA), polystyrene (PS), and random copolymers P(SxMMA1 - x) were mixed pairwise, in different compositions. Finely dispersed phase structures were produced in the blends, with domains in the submicron range. The structure patterns were considerably perturbed by the stress fields in the extruder. Domain-matrix and co-continuous morphologies were obtained, in a distribution controlled mainly by the viscosity ratio. Annealing after extrusion led to structure coarsening, whereby the patterns were changed until a steady state was established. Sometimes, matrix inversion was observed.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350809
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 181
    Electronic Resource
    Electronic Resource
    Effect of short chain branching on the viscoelastic behavior during fatigue fracture of medium density ethylene copolymers (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 786-793 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A method to determine viscoelastic changes in medium density polyethylene (MDPE) pipe specimens associated with the crack tip during fatigue crack initiation (FCI) and propagation (FCP) experiments is described. The load-displacement curves are analyzed to obtain the phase angle, δ. Changes in δ are related to the number of cycles of crack initiation of three different MDPE copolymers: hexene (H), butene (B), and methyl pentene (MP) copolymers. These changes are related to craze formation and growth at the notch tip, leading to crack initiation and to the irreversible work, Wi, expended on them. Within a given material, step wise increments in δ distinguish the onset of crack initiation and the brittle-to-ductile transition in crack growth. The magnitudes of tan δ and Wi are noted to be in quantitative agreement with the resistance of the three copolymers to FCI and brittle propagation that rank in the order: isobutyl (MP) 〉 ethyl (B) 〉 butyl (H). Similar crystallinity of the three copolymers insinuates a hypothesis that variance in the nature of chain entanglements associated with the respective branch type might be accountable for the observed differences in viscoelastic character. The final stage of failure by ductile tearing is dominated by large scale plastic flow that seemingly overshadows the material differences governing time dependent brittle fracture.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350908
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 182
    Electronic Resource
    Electronic Resource
    Application of statistical experimental strategies to the process optimization of waterborne polyurethane (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 722-730 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A modified acetone process for the preparation of aqueous polyurethane (PU) dispersion is investigated. PU dispersions were prepared by polyaddition of isophorone diisocyanate (IPDI) to poly(tetramethylene ether glycol) (PTMG) and dimethylolpropionic acid (DMPA), followed by neutralization of pendant COOH groups with triethylamine (TEA). The resulting prepolymer chain was then extended through reaction with an ethylenediamine (EDA) derivative bearing sulfonate groups. The effect of such preparation conditions as catalyst (dibutyltin dilaurate, DBTDL) concentration, the acetone/PU ratio, phase-inversion temperature, agitation rate, and water-addition rate on the average particle size of aqueous PU anionomer dispersions is systematically studied using fractional factorial design and response surface methodology. Fractional factorial analysis indicates that the effects of the acetone/PU ratio, phase-inversion temperature, water-addition rate as well as the two factor interactions of DBTDL concentration and phase-inversion temperature, of the acetone/PU ratio and phase-inversion temperature, and of acetone/PU ratio and agitation rate are the key variables influencing average particle size of PU dispersions. Empirical models for average particle size are fitted and plotted using central composite experimental design as contour diagrams in order to facilitate examination of the average particle size results. The results show that for a 100 g PU anionomer containing 0.311 wt % COOH and 1.51 wt % SO3H groups, a minimum number-average particle size of the dispersion ∼ 25 nm can be obtained under an acetone/PU ratio, water-addition rate, phase-inversion temperature, catalyst concentration, and agitation rate of 3.65, 2 mL/min, 50°C, 150 ppm and 350 rpm, respectively.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350812
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 183
    Electronic Resource
    Electronic Resource
    Master curve approach to polymer crystallization kinetics (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 733-740 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Nonisothermal crystallization kinetic data obtained from differential scanning calorimetry (DSC) for a poly(ethylene terephthalate) are corrected for the effects of temperature lag between the DSC sample and furnace using the method of Eder and Janeschitz-Kriegl which is based on experimental data alone without resort to any kinetic model. A method is presented for shifting the corrected nonisothermal crystallization kinetic data with respect to an arbitrarily chosen reference temperature to obtain a master curve. The method is based on experimental data alone without reference to any specific form of kinetic model. When the isothermal crystallization kinetic data for the same material are shifted with respect to the same reference temperature, a master curve is also obtained which overlaps to a large extent the corresponding master curve from nonisothermal data. It follows that nonisothermal DSC measurements provide the same crystallization kinetic information as isothermal DSC Measurements, only over a wider range of temperatures. The shift factors obtained from experimental data alone are compared in turn with the corresponding values calculated from the Avrami equation, the Hoffman-Lauritzen expression, and the Nakamura equation as a means of evaluating these models individually. It is concluded that the Avrami equation is very good at describing isothermal crystallization kinetics, the Hoffman-Lauritzen extrapolation of the limited isothermal data to a wide range of temperatures is quite good, and the Nakamura equation yields reliable crystallization kinetic information over a narrower range of temperatures than nonisothermal data alone without using any specific model.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350902
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 184
    Electronic Resource
    Electronic Resource
    The effect of curing of unsaturated polyester resin on the dynamic relaxation time (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 754-758 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of hot curing of unsaturated polyester resin on the dynamic relaxation time was studied using dielectric measurements along with two dynamic mechanical measurement methods. It was found that the dynamic response during cure was a material frequency dependent property and did not depend on the measurement method. All relaxation times, measured during cure, by all three measurement methods used, converged to a single equation: τ(t)av=atb where t= curing time, a, b=constants. The increase of the relaxation time during cure followed the same trend as a friction factor, which was found to increase with conversion. The crosslinking density was found to increase slowly with conversion, while the relaxation time increased exponentially. These two different modes of behavior during cure explain the high resolution of dynamic measurements as a cure monitoring tool, which can easily detect small curing changes. This behavior of the relaxation time was explained by the sharp rise of activation energy due to a parallel decrease of free volume at high conversion.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350904
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 185
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351001
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 186
    Electronic Resource
    Electronic Resource
    Isothermal gas-assisted displacement of viscoplastic liquids in tubes (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 877-892 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Isothermal experiments on gas-assisted displacement of viscoplastic liquids in tubes show that a liquid coating remains on the tube wall. The thickness of this coating approaches 0.35 of the tube radius at high gas penetration rates, the asymptotic limit previously observed for Newtonian liquids. At low gas penetration rates, the viscoplastic coating is much thinner than its Newtonian counterpart. During the displacement process, the gas front moves faster than the liquid front and, prior to blowout, it rapidly accelerates as the amount of liquid downstream of the gas is depleted by the liquid coating. Based on these observations, a simple isothermal model is developed to describe the gas-liquid dynamics. This model provides an insight into the gas-assisted injection molding process in which the injection of molten plastic into a mold is assisted by a pressurized gas. In particular, the results show that the wall thickness around the hollow cores in gas-assisted parts is set during processing by the solid skin and a thick molten layer. The thickness of the molten layer depends on the gas penetration rate and the viscous behavior of the molten plastic. By coupling the isothermal model with a one-dimensional heat-transfer analysis, the gas penetration rate is shown to be several orders of magnitude higher than the plastic freezing rate, so that most of the heat transfer between the melt and the gas occurs after the mold is filled.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351102
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 187
    Electronic Resource
    Electronic Resource
    Quiescent nonisothermal crystallization kinetics of isotactic polypropylenes (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 797-804 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Recently, a model was developed for the nonisothermal crystallization of normal alkanes with chain lengths between 30 and 50. The model was derived based on the fundamental equation of Ozawa for nonisothermal crystallization, the surface nucleation theory, and the growth rate theory for extended chain crystals. In this paper, the proposed model is modified and extended to the case of polymer crystallization. Experimental differential scanning calorimetry data for three isotactic polypropylene resins with different molecular weights are presented at five cooling rates from 2 to 40 K/min. Model predictions are in excellent agreement with the experimental data for the three polymers at low and high supercoolings.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351002
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 188
    Electronic Resource
    Electronic Resource
    The effect of particles on failure modes of filled polymers (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 813-822 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of rigid particles on the fracture mode of polymers that yield with necking was analyzed theoretically with a model of regularly arrayed spherical particles. The adhesion between a polymer and particles was assumed to be weak, and particles were assumed to debond from the polymer before necking. A linear decrease in engineering draw stress with an increase in the filler content was derived. An increase in filler content leads to a transition in deformation mechanism. The transition depends on the ability of the polymer to strain-harden. If the ability to strain-harden is insignificant and the engineering fracture stress (strenght) of the polymer is lower than its yield stress, the transition is from ductile to brittle fracture. If the ability to strain-harden is essential and the strength of the unfilled polymer is higher than its yield stress, the transition (ductile-to-ductile) is from neck propagation to uniform ductile yield. The critical filler contents were determined for both transitions from the properties of an unfilled polymer. The ductile-to-ductile transition without embrittlement is possible if the strength of the unfilled polymer is higher than its yield stress. Results for polymers filled by weakly bonded particles were compared with polymers filled by particles that debond after the yield stress.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351004
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 189
    Electronic Resource
    Electronic Resource
    Micro scale flow behavior and void formation mechanism during impregnation through a unidirectional stitched fiberglass mat (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 837-851 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Liquid composite molding (LCM) processes such as resin transfer molding (RTM) and structural reaction injection molding (SRIM) have been perceived as high potential processes for the near-net-shape manufacturing of composite parts. This paper addresses two major issues in LCM technology: fiber wetting and void formation during mold filling. Flow visualization experiments were carried out to develop a better understanding of the flow induced voids. The formation and elimination of voids were studied using several liquids and a unidirectional stitched fiberglass mat. Void formation was correlated to capillary number and liquid-fiber-air contact angle.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351006
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 190
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351101
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 191
    Electronic Resource
    Electronic Resource
    Characterization of poly(3-octylthiophene). II: Melt rheological characterization (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 868-875 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The poly(3-alkythiophenes) are electrically conducting polymers which are of particular interest due to their melt-processibility. We have studied the melt properties of poly(3-octylthiophene) (P3OT) by dynamic rheological measurements at temperatures between 180 and 250°C. The samples investigated have molecular weights in the range Mw = 30,000 to 400,000 and have been carefully characterized by dilute solution techniques, Residual iron chloride, a reagent used in the polymerization of these materials, was found to cause a high degree of crosslinking in the polymer melt. By contrast, samples which had been carefully purified demonstrated a negligible rate of crosslinking in a nitrogen atmosphere; however, the presence of air and higher temperatures were found to increase the rate of crosslinking substantially. The temperature dependence of the viscoelastic properties was characterized according to the principles of time-temperature superposition, and the influence of molecular weight was also evaluated. Overall, the rheological behavior was determined to be similar to that commonly observed for linear flexible polymers, which is in agreement with the results of our solution characterization of these materials.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351009
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 192
    Electronic Resource
    Electronic Resource
    Weldline strength in glass fiber reinforced polyamide 66 (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 893-901 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Presence of weldlines introduces an element of uncertainty to the performance of injection molded parts. Weldlines are particularly problematic in reinforced plastics because, unlike molecular orientation in neat polymers, the flow induced fiber orientation does not relax. This paper deals with the structure and mechanical behavior of weldlines in glass fiber reinforced nylon 66, a plastic known for excellent fiber-matrix adhesion. Two molds were used to generate weldlines: a double gated tensile sample shaped cavity in which the weldline is formed by a head-on collision of melt fronts flowing in opposite directions and a film gated rectangular plaque with a circular insert in which the weldline formation behind the insert is followed by additional flow. In both cases the weldline zone is several millimetres wide: in the plane where the melts fronts have met fibers are oriented parallel to this plane (random-in-plane in the double-gated cavity and unidirectional in the cavity with insert). The transition zone between the weldline plane and the rest of the sample is characterized by an increased presence of microvoids. Weldline tensile depends little on the fiber concentration and on the sample shape or thickness: values close to the matrix strength are found: in samples without weldlines strength increases with the fiber content. However, in instrumented impact penetration test during which the material is subjected to multiaxial loading, the weldline effect appears negligible.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 193
    Electronic Resource
    Electronic Resource
    Crystal orientation and twinning in cold-rolled ultrahigh molecular weight polypropylene (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 911-920 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The mechanisms of plastic deformation in cold-rolled ultrahigh molecular weight polypropylene (UHMWPP) have been explored by means of wide angle X-ray (WAXD) pole figures. The melt crystallized UHMWPP slabs were rolled unidirectionally in a two-roll mill at 408 K as well as in the cross (transverse) direction. In the unidirectional rolling, all reciprocal lattice vectors of (110), (040), and (130) were found to orient preferentially in the film normal (thickness) direction. The cross-rolling of UHMWPP shows the preferential orientation of the above plane normals in the film thickness direction, but the distribution of poles broadens toward the transverse direction. Such orientation behavior is very different from that of conventional cold-rolled polypropylene. Various orientation mechanisms involving the orientation of lamellae in the film plane, twinning of the (110) plane and slippage mechanisms have been taken into consideration to account for the observed pole figures. A theoretical simulation has been carried out based on an orientation distribution function approach by introducing a slippage angle along the maximum shear stress in conjunction with intralamellar slip around the transverse direction. This model simulation conforms closely with the experimental WAXD pole figures of the (110), (040), and (130) planes.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 194
    Electronic Resource
    Electronic Resource
    Chaotic mixing in the enhanced mixing simulatorThis paper is based on Chapter 5 of the Second Semiannual Report and Chapter 7 of the Third Semianual Report of the “Polymer Mixing Study” by the Polymer Processing Institute. These two reports appear in January and August, 1991, respectively. (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 929-941 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The mixing performance of an experimental device - the enhanced mixing simulator (EMS) - is studied in this paper. In this device, the Couette flow is perturbed laterally, so that uniform and quick mixing can be achieved. Numerical simulation of the mixing in EMS flows is performed, which shows good agreement with the experimental results. Spline interpolation and advanced integration techniques are used in particle tracking, so that accurate results are obtained at low costs. Poincaré sections are used to study the long-term mixing behavior. The uniformity of the simulated mixture is evaluated using statistical approaches - the variation coefficient and the Kolmogorov test. The Kolmogorov test is adequately implemented for our purpose and incorporated with efficient sorting algorithms. The mixing rate is determined from the time evolution of uniformity during mixing. It is also shown that although the Lyapunov exponent can identify chaos, it does not measure the mixing rate. Optimal design of the EMS is discussed.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 195
    Electronic Resource
    Electronic Resource
    Dynamic simulation of flow-induced fiber fracture (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1022-1030 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A dynamic simulation method has been developed of the fracture process of a fiber in a flow field using the particle simulation method proposed i a previous paper. The fiber is modeled with bonded spheres as a fiber model. The flexibility of the fiber model is altered by changing three parameters of the stretching, bending, and twisting constants between adjacent spheres. The stress induced in each bond of the fiber model as a result of deformation is formulated using displacement of the bodn distanc, bond angle, and torsion angle fr each pair of spheres. After deformation, the fiber model fractures at the bond at which the stress surpasses the strength of the fiber. The motion of the fiber model in a flow field is determined by solving the translational and rotational motion equations for individual spheres under the hydrodynamic force and torque exerted on them. The correctness of the method and formulation was verified by comparing the simulated deflection curve of a cantilever beam (with a concentrated load at the end) with the theoretical curve. Good agreement was found in both the deflection and slope of the beam. The fracture process of a fiber after bending deformation in a two-dimensional siimple shear flow was simulated under assumptions of an infinitely dilute system, no hydrodynamic interaction, and a low Reynolds number of a particle. The calculated critical conditions of the flow field for fiber fracture were compared with Forgacs and Mason's theoretical ones. Simulated values of the fracture condition of the fluid shear stress related to the Young's modulus of a fiber agree with theoretical ones over an aspect ratio of 15.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351210
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 196
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351301
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 197
    Electronic Resource
    Electronic Resource
    On the structure/properties relationships in photoinitiators of polymerization (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1061-1065 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The choice of photoinitiators is partly governed by the requirement of a high curing speed. Many reactive monomers and efficient photoinitiators have been synthesized and are commercially available. However, improved photoinitiator systems, exhibiting increasingly faster curing speeds and/or increased photosensitivity, are increasingly required. The intrinsic reactivity in the exicited states determines te interest of a given photoinitiator with reference to its efficiency. However, other factors e.g. high molecular absorption coefficients and a broad spectral absorption range, synergistic effects, yellowing, extractability, and th effect on the long-term stability, must be considered as important. An attractive field of research and development is found in the role played by decisive parameters affecting the reactivity of a given structure, such as chemical substitution in well-chosen positions, the character of water solubility, acid release ability, and copolymerization potential. Laser spectroscopy proved a most convenient tool for the real time investigation of the excited state dynamics and the processes involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351215
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 198
    Electronic Resource
    Electronic Resource
    Morphology and mechanical properties of epoxy resins containing functionalized perfluoroether oligomers (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1069-1076 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Chain extended perfluoroether oligomers were found to be miscible with bisphenol epoxy resins at all concentrations. These were evaluated as modifiers for anhydride cured resin systems, taking advantage of the carboxylic acid functionality at the chain ends. By altering the mixing and curing procedure different two-phases morphologies could be obtained varying from fine co-continuous networks, which produced transparent castings, to opaque systems consisting of precipitated heterogeneous particles. While the Tg and flexural modulus were found to be slightly lower than the control cure resin, the addition of the fluoroligomer modifier produced large increases in flexural strength, ductility, and fracture toughness. Samples with an IPN type morphology were found to exhibit an increase in ductility after aging at 200°C for three weeks proportionally to the concentration of fluoroligomer used.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351302
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 199
    Electronic Resource
    Electronic Resource
    The leveling of thermosetting waterborne coatings. Part II: Drying of coated wet films (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1098-1105 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Evaporation behavior of water/solvent blends was estimated using the universal functional activity coefficient, UNIFAC, method. The evaporation rate from a free surface of a waterborne coating, WBC, containing a co-solvent was experimentally determined. These results were used to estimate the evaporation rate from wet films of a WBC containing a variety of co-solvents with a range of initial thickness. Knowing the composition of the WBC during the drying process, the change in the viscosity and the surface tension was determined. The results strongly support the development of a surface tension gradient in the film. It is also suggested that a surface tension gradient would accelerate the leveling of the ribs if a proper co-solvent were employed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351305
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 200
    Electronic Resource
    Electronic Resource
    Effect of casting solvent on the heterogeneity of films of polymer blends (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1113-1116 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The miscibility window of the 50/50 w/w poly(styrene-co-4-vinylphenyl)-dimethylsilanol/poly(n-butyl methacrylate) (ST-VPDMS/PBMA) blends prepared from toluene was studied and determined to be in the VPDMS composition range of 4 to 18 mole% in the copolymers. The observed miscibility window was to be compared to the range of 9 to 34 mole% found for the blends prepared from methyl ethyl ketone which was capable of competing for hydrogen bonding. The fact that the observed miscibility windows are influenced by the choice of solvents illustrates that an equilibrium state of polymer mixing is not always attained in solvent casting films and that caution needs to be exercised in studying polymer miscibility when solvent cast films are used.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351307
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...