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  • Chemical Engineering  (1,071)
  • Biochemistry and Biotechnology  (732)
  • 1980-1984  (1,803)
  • 1983  (951)
  • 1982  (852)
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  • 1980-1984  (1,803)
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  • 1
    Electronic Resource
    Electronic Resource
    Modeling of polymeric film-blowing processesPresented at the 52nf Annual Meeting, Society of Rheology, February 1981. (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 172-181 
    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: Industrial film-blowing processes are characterized by large deformation rates, rapid changes of temperature and high stress levels. A pilot scale process was set up to simulate these variables. The pivotal element in modeling the process is a rheological constitutive equation which describes the fluid properties accurately over the entire range of conditions encountered; it was found that contributions to the stress in the material which arise out of the changing thermal history of a fluid element were a significant fraction of the total. When the deforming film is subjected to stretching but to little or no blowing, the axial stresses in the film are predicted excellently by the model under both isothermal and non-isothermal processing conditions. With rapid blowing and major deviations from uniaxial extension, the axial stresses are predicted less well, but still satisfactorily, under the conditions used. In no case are the circumferential stresses predicted accurately: i.e. unequal biaxial extensional deformations represent complications which have not been resolved.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220307
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  • 2
    Electronic Resource
    Electronic Resource
    A dynamic mechanical study of the curing reaction of an unsaturated polyester (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 254-259 
    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 curing process of an unsaturated polyester was followed by employing the dynamic spring analysis (DSA) technique attached to the Rheovibron viscoelastometer. The storage and loss moduli and the gel times of the resin with various concentrations of initiator (methyl ethyl ketone peroxide) were determined at several temperatures. The activation energy for the curing process studied was about 40 kJ/mol. Temperature effects on films partially cured below the ultimate glassy transition temperature (Tg) were studied similarly using the tensile mode on the Rheovibron from room temperature to 120°C. Two modulus peaks were observed upon heating and these were independent of precure conditions. The lower temperature peak was the result of continued curing and the higher temperature peak was attributed to the glassy relaxation of the cured product. The DSA technique were found to be useful for characterization of the curing process and the results showed good qualitative agreement with those obtained by tensile measurements using cast films when the shapes of the curves were compared.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220407
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  • 3
    Electronic Resource
    Electronic Resource
    Property-morphology relationships of polymethylmethacrylate/polyvinylidenefluoride blends (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 234-240 
    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 investigation was conducted to establish property-morphology relationships in polymethylmethacrylate/polyvinylidenefluoride (PMMA/PVDF) blends. All blends were compounded in a twin-screw extruder and then processed by injection molding Mechanical properties of blends of various compositions were studied by dynamic mechanical and impact strength measurements. The presence of crystalline regions in blends was determined by Differential Scanning Calorimetry (DSC). Morphology of fracture surfaces of blends was studied by Spinning Electron Microscopy (SEM). PMMA/PVDF blends were found to form compatible mixtures over a wide range of blend composition. Changes in dynamic mechanical properties upon annealing were found to be a direct function of blond morphology. Electron microscopic evidence showed no signs of phase separation. DSC measurements detected crystalline regions in all blends containing 40 percent or more (by weight) PVDF.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220404
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  • 4
    Electronic Resource
    Electronic Resource
    The limiting pressure-velocity (PV) of plastics under unlubricated sliding (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 248-253 
    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 limiting pressure-velocity (PV) of plastics materials under normal contacting pressure P and sliding velocity V when the sliding goes on continuously unlubricated has been discussed theoretically in this study. The sliding friction tests between the rotating edge of a hollow cylinder against a stationary metal surface were carried out in room air and when the metals were cooled with circulating water.The results obtained were as follows: The relation between PVmax and the critical temperature τbmax of the surface above which ordinary frictional conditions are not maintained may be represented by the following formula, \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {{\rm PV}_{max} = C(\tau _{bmax } - \tau _a)} & {(1)} \\ \end{array} $$\end{document} Where C = Hn/μk, and H is the mean total heat conductivity between materials and environment in cal/cm2. °C · s, n the area ratio of heat radiation surface to frictional surface, μ the kinetic frictional coefficient, k the thermal equivalent of frictional work in cal/kg · cm · s, and τa the cooling or environment temperature.The value of C ranges from 1 to 10 in cal/kg · cm s · °C, and the value of PVmax from 45 to 750 in kg/cm2 · cm/s under prevailing room temperature air cooling in this experiment, however, the value of C has been increased about 2.3 times as much as those values by circulating water of 2°C around the lower side of the test piece.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220406
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  • 5
    Electronic Resource
    Electronic Resource
    Solid-phase backward extrusion of thermoplastics (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 269-279 
    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 backward extrusion process was studied as a means of forming projections and ribs on flat sections of thermoplastic parts. The simplified, open-die axisymmetric and plane-strain extrusion cases were mainly considered. The results were applied to the development of a continuous solid-phase-forming process. Commercial-grade polycarbonate (PC), polypropylene (PP), and polystyrene (PS) were used in the investigation. The projection height and extrusion loads in the unconstrained extrusion were measured as a function of the initial temperature of the material, the load hold time, and geometric variables. Cold dies were used in the experiments, and the samples were kept below their melt temperatures. The dimensional recovery of the flange section of the formed samples was also measured as a function of the hold time for given initial temperature and geometric variables. The slab and the upper-bound methods-in plasticity analysis were used to theoretically derive the projection heights and forming loads. The degree of correlation between the predictions and the experimental results depended on the estimates used for the frictional factors at the interfaces between the deforming material and the dies.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220502
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of compaction rate during the cold forming of polymeric powders (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 300-306 
    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 many plastics processing methods, both conventional and novel, plastic powders or granules are subjected to pressure. The pressure transmissibility through the powder has an important effect on the success and efficiency of the process, and so it is desirable to be able to predict the pressure at any point from a knowledge of the applied pressure and the geometry of the system. To examine this pressure transmissibility effect, poly(vinylidene chloride) powder has been compacted in a metal die under different rates using either load or displacement control. It has been found that rate effects are particularly important for loading rates greater than 8 MPa/s and displacement rates greater than 7.5 mm/s. The ratio of transmitted pressure (P2) to applied pressure (P1) has been measured for a range of compact geometries, and it has been found that the ratio is approximately constant during the latter stages of the compaction process. Various laws for predicting the transmitted pressure have been studied, but it has been found that the simplest equation that agrees with the data is of the form \documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{P_2 }}{{P_1 }} = e^{- \alpha \mu ch/D} $$\end{document}
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220506
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  • 7
    Electronic Resource
    Electronic Resource
    Molecular weight distribution of polyethylene terephthalate in homogeneous, continuous-flow-stirred tank reactors (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 314-323 
    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: Poly(ethylene terephthalate) (PET) formation in homogeneous, continuous-flow-stirred tank reactors (HCSTRs) operating at steady state has been simulated. The feed to the reactor is assumed to consist of the monomer bis-(hydroxyethyl) terephthalate and monofunctional compound (MF1) cetyl alcohol. The overall polymerization is assumed to consist of the polycondensation, reaction with monofunctional compounds, redistribution, and cyclization reactions. At a given time, the reaction mass consists of polyester molecules (Pn), polyester molecules with an ending of molecules of monofunctional compound (MFn), and cyclic polymers (Cn). A mass balance for each of these species in the reactor gives rise to a set of algebraic equations to be solved simultaneously. The MWD calculations show that the redistribution reaction plays a major role and cannot be ignored, This result is in contrast lo the observation for semi-batch reactors, for which redistribution becomes important when the cyclization reaction is included. For the same residence times of semi-batch and HCSTRs, the latter gives considerably lower-number average molecular weight, Nav, and polydispersity index, ρ. However, for the same conversions, the ρ for CSTR is higher. The concentration of the monofurctional compound, [MF1]0, in the feed and the reactor temperature both influence ρ, but the effect is small within the range studied.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220508
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  • 8
    Electronic Resource
    Electronic Resource
    An improved lattice-fluid equation of state for pure component polymeric fluids (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 345-348 
    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 Fluid-Lattice Theory (Ising Fluid), recently tested by Lacombe and Sanchez, has been modified by introducing the typical Flory's surface-to-volume ratio of the characteristic-segment of a polymeric liquid. This surface-to-volume ratio is not an adjustable parameter. It is obtained from Bondi's tabulations. The resulting new equation of state has three adjustable parameters per component and it represents a definite improvement for the fitting of P-V-T data for polymeric liquids. Extension to mixtures is not tested in this work but, in principle, it can be done by well-established methods.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220603
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  • 9
    Electronic Resource
    Electronic Resource
    Capillary and slit flow behavior of concentrated solutions of a rod-like polymer (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 521-527 
    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: This paper is concerned with the flow behavior of isotropic solutions of the rod-like polymer, poly(p-phenyleneterephthalamide) (PPT), in 100 percent sulfuric acid. Studies include entry flow visualization in a slit die and solution fracture, and die swell in capillaries and a slit die. It was observed that solutions of PPT exhibit nearly negligible die swell, a slip-stick type of fracture that disappears at high shear rates, and radial entry flow patterns similar to Newtonian fluids. Fracture was associated with the plateau in the shear stress vs shear rate curve. Because values of the wall shear stress (τw.) obtained from capillary measurements were in good agreement with those obtained from a cone-and-plate rheometer and values of the loss modulus (G″) obtained from small-strain dynamic oscillatory measurements, it is believed that the rheological properties lead to the flow instability. These results are in agreement with the predictions of a recent theory by Doi and Edwards for concentrated solutions of rod-like molecules. Data are also presented for a flexible chain polyamide, nylon 6,6, in 100 percent H2SO4 for the purpose of comparing the flow characteristics of rigid and flexible chain polymers.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220902
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  • 10
    Electronic Resource
    Electronic Resource
    The elastic change of volume in pressurized bottles made from polymeric materials (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 472-477 
    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 relations describing the elastic change of volume of thermoplastic cylindrical pressurized containers are presented. Discussions have been made on various cases including isotropic (i.e., un-oriented), uniaxially, and biaxially oriented materials. These relations are expected to be helpful for selecting the optimum processing conditions (i.e., draw ratio) in order to achieve the desired properties of polymeric pressurized containers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220804
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  • 11
    Electronic Resource
    Electronic Resource
    The hydrolytic stability of some commercially available polycarbonates (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 370-375 
    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 number of commercially available polycarbonates, including formulations made flame retardant by two different modifications, have been exposed to conditions producing moderately rapid hydrolysis. Hydrolysis rates were calculated from molecular weight data determined by gel permeation chromatography and, in some cases, from melt flow rate data. The rates calculated by the two methods are in good agreement. In general, the standard formulations containing minimal additive packages are the most hydrolytically stable. Although one relatively new flame retardant polycarbonate demonstrates generally good resistance to hydrolysis, most of the flame retardant formulations appear to be quite susceptible to hydrolytic degradation. For these materials, hydrolysis under conditions encountered in use could cause significant decreases in impact strength within a few years.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220608
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  • 12
    Electronic Resource
    Electronic Resource
    Low temperature thermal aging of ethylene vinyl alcohol copolymers (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 382-387 
    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 crystallites of semicrystalline polymers formed at low temperatures are subject to partial partial melting and recrystallization resulting in a systematic increase in the size and perfection of the nascent crystallites. Differential scanning calorimetry (DSC) and x-ray studies suggest that ethylene-vinyl alcohol copolymers (EVOH), in particular, may undergo these secondary crystallization processes upon storage at temperatures far below Tm. DSC scans have been run on “as received” and quenched samples; the mole percent of vinyl alcohol in the copolymers studied was 0, 62, 70, 72, 82 and 100 percent. Tests on secondary crystallization kinetics, performed at different temperatures, further confirm the hypothesis of an increased degree of perfection (lamellar thickening) of the bulk crystallites achieved upon long term storage at temperature between Tg and Tm.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220610
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  • 13
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    Rheology of polymer blends: Simultaneous slippage and entrance pressure loss in the ethylene-propylene-diene (EPDM)/viton system (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 507-511 
    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: Because the exact nature of the mechanism governing the marked viscosity reduction in the highly incompatible EPDM/“Viton” fluoroelastomer system is not fully understood, a study was undertaken to shed more light on the phenomenon. Interracial. Slippage in the blend has been suggested as the mechanism by which a substantial reduction in the melt viscosities of either component takes place upon addition of a small amount of the other, In the present investigation, a Mooney slip analysis demonstrated wall slippage in the EPDM/Viton system over the shear stress range of 40 kPa to 160 kPa. The capillary surface was examined for evidence of coating by the minor component of the blend (Viton), and 9-fold enrichment was found by elemental analysis. However, on no occasion was pure Viton found. In other experiments, the dynamic linear viscoelastic properties and the transient squeezing flow response of the blend were found to be no different from those of the neat elastomer. In addition, the slip velocity in a capillary (and consequently, the viscosity-lowering effect) was reduced by a factor of 2 to 3 in capillaries with a 90° included entrance angle. It is postulated that the reduction in the flow resistance for the blend is unique to the sharp-entry capillary geometry and results from removal of Viton from the melt in the recirculating flow at the entrance. This material then feeds along the capillary wall, disrupting the already tenuous adhesion of the elastomer to the metal surface.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220809
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  • 14
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    Unsaturated polyesters from 2,2-dimethyl-1,3-propanediol (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 556-559 
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    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 series unsaturated polyesters were made from 2,2-di-methyl-l,3-propanediol, propylene glycol, fumaric acid, and isophthalic acid by a two-step fusion process. The effect of catalyst, conversion, composition, unsaturation, and styrene content were studied, and the relationship between composition and properties was established.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220907
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  • 15
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    Effect of the addition of ethylene-propylene random copolymers on the properties of high-density polyethylene/isotactic polypropylene blends: Part 1 - morphology and impact behavior of molded samples (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 536-544 
    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: Two random commercial ethylene-propylene copolymers (EPM) with different ethylene content have been added to binary isotactic polypropylene (iPP)/high density polyethylene (HDPE) blends by melt mixing in a Brabender-like apparatus. Impact Izod tests and a morphological analysis on the fractured surfaces of broken specimens have been performed and discussed, in order to improve the deficiency in toughness of the binary HDPE/iPP mixtures. The results show that the impact performance of both homopolymers and HDPE/iPP binary blends is strongly improved by the addition of the EPM copolymers. Such an effect is related to the fact that the overall morphology, as well as the mechanism and mode of fracture, are greatly modified by the presence of such additives. The extent is dependent on factors such as the nature of the matrix (HDPE or iPP), the composition, and the chemical structure and/or the molecular mass of the added copolymer.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220904
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  • 16
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    Masthead (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982) 
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    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.760221001
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  • 17
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    Estimation of injection pressure during mold fillingPresented in part at the “Second World Congress of Chemical Engineering,” Montreal, Canada, Oct, 4-9, 1981.This paper is a corrected reprint of the paper that originally appeared in POLYMER ENGINEERING AND SCIENCE, Mid-April, 1982, Vol, 22, No. 5. (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 589-593 
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    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: Dimensionless diagrams for estimating the bulk temperature of the flow front and injection pressure in the limit of small viscous generation are obtained. Also, a criterion for neglecting viscous generation is identified, The diagrams, based on the Lord and Williams model, refer to rectangular geometry and amorphous materials. A satisfactory comparison is obtained with literature data taken on polystyrene. A reasonable estimate of polyethylene injection pressure was obtained by roughly accounting for latent heat of crystallization through modified thermal diffusivity.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760221002
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  • 18
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    The relationship of carbon black dispersion to electrical resistivity and vulcanizate physical properties (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 601-609 
    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 degree of dispersion of carbon black in rubber is known to be a determining factor in the physical properties of the composite. It is important, therefore, to have a reliable, quantitative technique for assessing carbon black dispersion. It has been known for some time that the degree of dispersion of carbon black is reflected in its electrical resistivity. A resistivity instrument, developed by B. Boonstra, has been redesigned and constructed for use in this study. Factors that influence resistivity (i.e., black type, volume loading, and mixing time) are examined. Physical property and dynamic mechanical measurements are made, and their relationship to black dispersion is investigated. Light microscopy is also used to evaluate dispersion, and these data are compared to the resistivity results.
    Additional Material: 18 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760221004
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  • 19
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    On the dynamics and control of a plasticating extruder (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1095-1106 
    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 recent years, there have been many papers published on the application of process control to plasticating extruders. Much of the literature concentrates on the more classical control techniques. However, recent research has studied the application of stochastic identification techniques for building transfer function models for the extruder. In particular, the relationship of screw speed to die pressure and temperature has been studied. In the present work, both step tests and pseudorandom binary sequence tests were used to study the process dynamics of a 38 mm Killion extruder having a Iength-to-diameter ratio of 24:1. This study concentrates on the regulation of the extruder pressure in the face of its inherent surging characteristics. Variations in the quality of the feed plastic were studied through pulse and step changes in input polymer composition. Significant control problems resulted from measurement noise, which appeared at the same frequency as the screw rotation speed. Various mathematical filters to reduce the effect of this noise on the control variables were studied.
    Additional Material: 17 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760221707
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  • 20
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    Siloxane-poly(Methylmethacrylate) amphoteric blends (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1123-1126 
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    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: Poly([4-(methacryloyloxy) butyl]pentamethyldisiloxane), PMBPD, has been prepared for the first time. At the weight average molecular weight of 55,900, it is a clear, viscous liquid with a glass transition temperature, Tg, of 236K. Copolymers with methylmethacrylate have also been prepared. The homo-and copolymers, all of which have methacrylate backbones with pendant siloxane groups, were blended with poly(methyl-methacrylate), PMMA. Using the existence of a single Tg as a definition of miscibility, it was found that blends of either PMMA or PMBPD with random copolymers are miscible. However, in spite of a clear appearance, the blend of the two horriopolymers were found to have two distinct Tgs.
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    URL: http://dx.doi.org/10.1002/pen.760221712
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    Recent advances in interpenetrating polymer networks (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1143-1152 
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    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 review the synthesis, morphology, and physical and mechanical properties of IFNs as well as the related pseudo-IPNs, in which only one of the polymers is crossliriked. Recent studies have shown that the degree of phase separation achieved in these materials is strongly dependent on the compatibility of blends of the linear polymer constituents of the IPN components as well as the kinetics of chain extension and the presence of grafting between component polymers. We illustrate this by a series of IPNs consisting of a polyurethane and an acrylic copolymer. The acrylic is a typical automotive enamel. An enhancement in properties results, which is dependent on the amount of grafting and the kinetics of polymerization. Also discussed are IPNs of a polyurethane and an epoxy, which exhibit a synergism in adhesive properties, and IPNs of a RIM polyurethane with several epoxies and unsaturated polyesters. In addition, also reported are the preliminary studies on the first successful preparation of a three-component IPN, consisting of a polyurethane, an epoxy, and an acrylic.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760221715
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    Development of industrial polyolefin blends using melt rheology data (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1153-1165 
    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 review of current knowledge of the composition dependence of polymer-blend processability and morphology shows that development of industrial blends requires use of a semiempirical approach, based on the particular rheological composition (PRC) concept. Selecting blend composition in the close proximity to PRC and employing factorial experiments for the mixing process allows the development of successful industrial polyethylene/polypropylene blends designed for film and blow-molding applications.
    Additional Material: 16 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760221716
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    Composition and processing effects on the properties of one-component polyurethanesPresented at Second World Congress of Chemical Engineering, Montral, Canada, October 4-9, 1981. (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1177-1183 
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    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 polyurethane consisting of a poly(propylene oxide) soft segment and a diphenylmethane diisocyanate - hydroquinone di-(b̃-hydroxyethyl) ether (HQEE) hard block has been characterized over the composition range of 30 to 60 percent hard block. The flexural modulus varied from 60 to 900 MPa over this composition range. The elongation was approximately 250 percent at the lower hard block contents but fell below 100 percent at 60 percent hard block. Differential scanning calorirnetric measurements showed that the crystallinity associated with the hard phase increased with increasing hard block content but decreased with increasing cure temperature. The heat sag was found to decrease with increasing hardblock and increase with increasing cure temperature. A material with properties comparable to current fascia materials had a significantly better heat sag resistance than a current RIM (reaction injection molding) polyurethane. The combination of the solid chain extender, HQEE, and a solid catalyst, zinc stearate, lowing it to be processed as a one-component resin having a pot life of greater than 8 h at 20°C al-injection molding machines. The one-component nature of the resin has made it possible to use a continuous in-line mexer and to reduce the amount of scrap by using cold runner molds. In addition, any scrap that is generated can be used as regrind in the system.
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    Fractography of polyethylene glycol dimethacrylate doped with polymethyl methacrylate (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1199-1204 
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    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 presence of polymethyl methacrylate (PMMA) can greatly affect the properties of materials made by polymerization of ethylene glycol dimethacrylate (EGDM). Fracture surfaces, examined by scanning electron microscopy, show a much wider range of morphologies in mist regions than observed in previous work on PEGDM alone. These morphologies are attributed to the moderation of brittle fracture by localized plastic deformation. It is suggested that the effect of PMMA is due to its segregation around clusters of highly cross-linked particles of PEGDM that, as a result, become more discrete and, hence, more susceptible to interparticle displacements during fracture. In agreement With this suggestion, the mist regions usually exhibit a particulate microstructure.
    Additional Material: 9 Ill.
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    Studies of epoxy resin systems: Part D: Fracture toughness of an epoxy resin: A study of the effect of crosslinking and sub-Tg aging (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1228-1236 
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    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 an epoxy resin system, diglycidyl ether of butanediol, DGEB, cured with 4-4′ diaminodiphenyl sulphone, DDS, has been studied by varying the crosslinking density and state of aging. A stable, but rough, crack propagation was observed with specimens that were 99 percent cured and quenched. When the extent of curing was less than 99 percent or the material was aged for more than 20 min at 62°C, crack propagation was of the unstable stick-slip nature. Aging was found to decrease the initiation fracture toughness dramatically, but the arrest fracture toughness was almost unchanged. This result was associated with a change of relaxation strength of the primary, a, transition with aging. An increase of crosslinking density was found initially to reduce the fracture toughness of this epoxy resin, but the fracture toughness increased after 87 percent of curing. The initial decrease of the fracture toughness was attributed to a decrease of relaxation strength of the primary transition (i.e., the area under the α-relaxation peak), while the increase of the fracture toughness after 87 percent curing was explained by the onset of the stablerough crack propagation, Micrographs taken by scanning electron microscopy-showed possible existence of blunting during crack propagation and a decrease of blunting with the extent of aging.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760221809
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    Equilibrium solubility and permeability of sulfur dioxide in epoxy resin of aliphatic diglycidyl ether (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 6-12 
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    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: Equilibrium sorption isotherms were obtained for the sulfur dioxide-epoxy resin of aliphatic diglycidyl ether system over a temperature range of 1° to 45°C. The sorption isotherms indicated the presence of Langmuir sorption due to specific interaction. This is uncommon for rubbery polymers, though similar behavior was also observed previously. Zimm-Lundberg's clustering analysis indicated a slight tendency for clustering of the penetrant molecules at low temperatures and higher activities. The number of Langmuir sites for sorption was found to be independent of temperature. The mobilities of the molecules sorbed in Henry's law mode and the Langmuir mode were found to be approximately equal. Predictions of the permeability values for this system are presented and compared with other data from the literature. The temperature dependence of different sorption parameters is presented and discussed in detail.
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    Tensile yield in poly(4-methyl pentene-1)Presented, in part, at the American Physical Society Meeting in Dallas, Texas, March 1982. (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 13-16 
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    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Uniaxial tension tests to the yield point were performed on a crystalline polymer, poly(4-methyl pentene-1) (PMP) as a function of temperature from 21° to 200°C at a strain rate of 2 min-1. After testing, the specimens showed considerable stress whitening as a result of microvoid formation. Yield energy was found to be a linear function of temperature extrapolating to zero at the melting point (240°C). Thus, the behavior of this crystalline polymer is similar to that of glassy polymers, but with the melting temperature, rather than the glass transition temperature, as the reference point. The ratio of thermal to mechanical energy input to produce yielding is an order of magnitude smaller for PMP than it is for glassy polymers. The ratio of yield stress to Young's modulus is about 0.02, which is typical for polymers. Yield stress is a linear function of log strain rate, which implies that yielding can be described as a segmental flow rate process in which the applied stress biases the activation energy. The activation volume is on the order of 20 monomer unit volumes and increases as the temperature increases. The activation energy is 19 kcal/mol.
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    Masthead (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983) 
    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.760230201
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    Residual stress craze and crack formation in poly(methyl methacrylate)Presented in part at the Fifth International Conference on Deformation, Yield, and Fracture of Polymers, Cambridge, U.K., 1982. (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 211-215 
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    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(methyl methacrylate) with a central circular hole are compressed, and crazes form on or after unloading, provided that the strain attains or exceeds a threshold value ∊t. Crazes induced in air are transformed rapidly to cracks, but environmental crazes are more stable. These residual stress crazes form at the diameter of the hole on a plane perpendicular to the applied stress direction. In contrast, during loading, crazes form on the vertical plane containing the hole axis. Unloading crazes are relatively insensitive to changes in strain rate, whereas loading erazes have a pronounced rate dependence. Environmental residual stress crazing exhibits an apparent rate sensitivity at constant time, but the critical applied strain ∊t is essentially constant, irrespective of rate, if the sample is in contact with the environment for a sufficiently long time to ensure that the minimum ∊t is obtained. Residual stress crazes appear to initiate at the equator of the hole, and the maximum tensile residual strain, indicated by a strain gauge, occurs in this position.
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    URL: http://dx.doi.org/10.1002/pen.760230409
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    Head-to-head polymers 27: Thermal degradation of head-to-head polyisobutylene (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 226-229 
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    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: Head-to-head polyisobutylene degrades at a maximum rate at 320°C, a temperature about 65°C lower than head-to-tail polyisobutylene. Under our conditions, head-to-tail (the regular polyisobutylene) degrades (as do many other disubstituted vinyl monomers) to a high yield of the monomer isobutylene. Surprisingly, head-to-head polyisobutylene also degraded, primarily to isobutylene. Liquid, low-molecular compounds, probably dimers, were also obtained from head-to-tail and head-to-head polyisobutylene. A mechanism of this degradation is proposed.
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    URL: http://dx.doi.org/10.1002/pen.760230412
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    Masthead (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983) 
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    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.760230501
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    A low-energy solvent separation method (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 230-237 
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    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 presents a new low-energy method to separate solvents from polymers. The method is based upon the lower critical solution temperature (LCST), a phenomenon exhibited by all nonpolar polymer-solvent systems. Three key issues concerning this new separation method are discussed for the specific system of high cis polybutadiene in a commercial grade n-hexane. The first issue, energy cost, is greatly reduced from present commercial separation processes by avoiding the liquid-vapor phase transition for more than half of the solvent. The predicted energy cost for the new method (not including inefficiencies) is about 15 percent of the present energy cost (including inefficiencies). The second issue, recycling of the dilute phase with terminator, is shown not to be a serious problem, and a solution is suggested based upon available methods. The third issue discussed, and perhaps the most difficult, is the physical separation of the two phases. This is solved by inducing spinodal decomposition, which leads to rapid gravity separation. Several alternative separation scenarios based upon this idea are presented at the end of the article.
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    URL: http://dx.doi.org/10.1002/pen.760230413
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    Masthead (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983) 
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    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.760230601
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    Design of two-stage extractor screws (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 299-305 
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    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 basis for design of two-stage extractor screws is developed with special focus on determining optimum design of the final pumping section in order to maximize pressure-generating capability. Departure from the conventional square-pitch helix angle of 17.7° appears justified in this section of the screw where pressure-development capability is critical to successful performance. Optimization can produce gains of 5 to 30 percent in pressure (or in corresponding length reductions), the exact benefits depending on the non-Newtonian behavior of the melt and on the optimization strategy selected.
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    URL: http://dx.doi.org/10.1002/pen.760230603
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    Properties of polyisobutylene-polyurethane block copolymers: I. Macroglycols from ozonolysis of isobutylene-isoprene copolymer (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 337-349 
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    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 properties of a series of polyisobutylene (PIB) based polyurethanes were studied and compared to those reported in the literature for polyether, polyester, and polybutadiene-based polyurethanes. Good phase separation was reflected in the invariance of the soft segment Tn with increasing hard segment content. Increasing hard segment content resulted in larger domains, higher modulus and lower ultimate elongation. The modulus above the soft segment Tn was higher than that previously reported for polyurethanes of similar hard segment contant; improved phase separation and short contour lengths of the PIB chains were cited as possible causes of this behavior. Stress-strain data indicated a change from isolated to interconnected domain morphology with incerasing hard segment contant. Generally similar trends were seen for all types of urethanes. The overall properties of polybutadiene polyurethanes were closest to those of the polyisobutylene polyurethanes studied. The properties of both of these systems were suggested to suffer from significant synthesis problems in urethane formation due to the incompatibility of the nonpolar hydrocarbon soft segment and the polar diol chain extender. Preliminary environmental tests indicated that polyisobutylene based materials exhibit improved hydrolytic stability and reduced moisture permeability compared to polyether and polyester polyurethanes and greater oxidative stability compared to polybutadiene based materials.
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    Vulcanization shrinkage of rubber articles with rigid armoring parts (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 350-353 
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    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 discusses the shrinkage characteristics of armored (reinforced) rubber articles for two types of boundary conditions: (a) cases where the armoring material is neither flexible nor thermoexpansive, and (b) cases where the armoring material has a finite thermal expansion between room and vulcanization temperature. A quantiative analysis of shrinkage strains and stresses is developed for the two boundary conditions.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760230609
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    An observation on the han-villamizar critical pressure concept in thermoplastic foams (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 354-355 
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    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: This note draws together the Han-Villamizar experimental observations on the critical pressure at which gas bubbles became visible in flowing thermoplastic melts and a simple method of predicting the equilibrium pressure based on gas solubility. It is shown that the observed pressure is 40 to 75 percent of the calculated pressure.
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    Dynamic mechanical studies of thermal aging in poly(vinyl chloride) (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 390-393 
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    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 effects of thermal aging on the dynamic mechanical properties of rigid poly(vinyl chloride) (PVC) and chlorinated poly(vinyl chloride) (CPVC) are examined in the glass transition (Tg) and β transition (Tβ) regions. PVC, when quenched through Tg and then annealed at 40°C, exhibits a sub-Tg peak in the loss modulus function. The position of the peak moves to higher temperatures with increasing annealing time. The effect is analogous to sub-Tg endothermic peaks previously observed by differential scanning calorimetry (DSC). A sub-Tβ peak in the tan δ or the loss modulus functions can be produced by quenching through Tβ. The effect of heating rate on the sub-Tβ peak is explored.
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    Effects of strain rate and temperature upon tensile properties of acetal copolymers (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 216-221 
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    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 strength and elongation to break of an acetal copolymer were measured at four elongation rates, from 0.2 to 20 in./min, at temperatures from 239 K to 339 K. Both strength and elongation results could be reduced to master curves by means of time-temperature superposition. The temperature dependence of the shift factors was given by an equation of the WLF form, with parameters close to those found for most amorphous polymers, at a reference temperature equal to the γ-transition temperature of the polymer. Extrapolation to much higher testing rates and to much slower creep rates was satisfactory. Similar but less extensive tests were run on two other samples with different molecular weights. The yield stress was independent of molecular weight, but elongation increased with increasing molecular weight at all conditions.
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    URL: http://dx.doi.org/10.1002/pen.760230410
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    The specification of orientation and its development in polymer processing (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 247-256 
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    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 critical review of the specification of orientation and its development in polymer-processing operations is presented. Orientation may in general be specified by orientation distribution functions, but is most conveniently expressed in terms of orientation factors which are second moments of the distribution. The Hermans orientation factor represents polymer-chain orientation for systems with fiber symmetry (uniaxial orientation) and the Hermans-Stein orientation factors express uniaxial orientation for each of the crystallographic axes of crystalline polymers. Biaxial orientation is, however, developed in tubular film extrusion, blowmolding and, indeed, all processing operations other than fiber formation. Orientation factors developed previously by the authors express biaxial orientation in terms of the angles between the machine and transverse directions and the polymer chain axis or crystallographic axes. In flowing polymer melts, the Rheo-Optical Law, which relates birefringence and stress, represents a relationship between polymer-chain orientation and stress. In vitrified polymeric glasses (e.g. polystyrene), the orientation factors are related linearly to the stress field at vitrification. This has been shown experimentally for melt spinning and tubular film extrusion. The results of studies of blowmolding and injection molding are consistent with this. The crystalline orientation factors have also been found to be determined by the stress field at solidification in melt spinning and tubular film extrusion.
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    URL: http://dx.doi.org/10.1002/pen.760230503
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    Super strong polymers in planar directions (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 266-270 
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    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 novel approach for producing multiaxially oriented polymers with ultrahigh mechanical properties in more than one direction is discussed. According to the approach, which is adaptable to conventional commercial processes, the polymer is processed in a contained geometry at a temperature near to but below the isotropic crystalline melting point under curvilinear flow conditions generated by the combined effects of a compressive force and a rotational force perpendicular to the compressive force. The process is demonstrated with thermoplastic and thermotropic polymers using simple torsional flow. The general features of the process and the properties of the multiaxially oriented polymers are discussed in view of the different flow conditions.
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    URL: http://dx.doi.org/10.1002/pen.760230506
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    Thermal conductivity of plastic foams (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 293-298 
    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 equation enabling the prediction of the thermal conductivity of plastic foams, without the aid of adjustable parameters, is proposed. The equation is based on a recurrent method, previously developed, that showed reasonable agreement with experimental results. Ways of decreasing the thermal radiation contribution are shown. In particular, the influence of cell size, radiation transmission through solid membranes, and low-emissivity boundary surfaces are analyzed. Errors involved in steady techniques of measuring the thermal conductivity associated with radiation are discussed.
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    The length of a transfer unit (LTU) for polymer devolatilization processes in screw extruders (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 323-327 
    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 this paper we introduce the concept of the length of a transfer unit (LTU) for polymer devolatilization and show that the LTU is an appropriate measure of the effectiveness of the process unit in which the devolatilization operation is conducted. The utility of the concept is demonstrated for the case when the process unit is a twin screw extruder for which values of the LTU were determined from experimentally measured values of devolatilization rates. Values of the LTU were found to depend solely on the fluid mechanics in the extruder as expected and were in good agreement with the predictions of a theoretical expression developed for the system that was studied. Finally, we discuss the implications of the LTU concept in relation to the engineering design and analysis of polymer devolatilization processes.
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    URL: http://dx.doi.org/10.1002/pen.760230606
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    Studies on whitening phenomena induced by some non-solvents on highly oriented glassy polymers (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 328-336 
    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: Whitening phenomena, characterized by optically opaque regions when a highly oriented glassy polymer is immersed in some liquids, were investigated as a function of temperature, extent of molecular orientation, different solvent and molecular weight, using oriented polymethyl methacrylate (PMMA) obtained by hot-stretching and cold drawn polycarbonate (PC). Whitened PMMA is highly porous resembling foamed plastics and shows the same Tg as in unwhitened PMMA, while whitened PC is denser with much smaller pores and exhibits melting behavior characteristic of solvent-induced crystallinity. Whitening progresses with a sharp boundary between whitened and unwhitened layers, which advanced at a constant velocity. This feature is similar to Case II transport. However, whitening differs from Case II sorption in that it only occurs in highly oriented polymers in contact with liquids of negligible sorption. Activation enthalpy of 44.1 and 39.7 kcal/mol has been found in a certain temperature range for PMMA/N-methyl formamide (N-MF) and PC/di-isopropyl amine (DIPA) respectively. At a given temperature, a higher extent of orientation leads to faster whitening process. Entropy correlation theory, in which the decrease in the configurational entropy (ΔSc) due to orientation is assumed to approximate an inerease in the activation entropy, was employed to correlate the dependency of the whitening rate on orientation. For hotstretched PMMA, where ΔSc is proportionl to \documentclass{article}\pagestyle{empty}\begin{document}$ (\alpha ^2 + 2/\alpha - 3) $\end{document} since affine deformation applies, a good correlation is observed. For cold drawn PC, correlation was poor, probably because ΔSc cannot be expressed to be proportational to \documentclass{article}\pagestyle{empty}\begin{document}$ (\alpha ^2 + 2/\alpha - 3) $\end{document}. In PMMA, when the molecular weight is in the same order as the average molecular weight between entanglements, the orientation and the whitening rate are both lower than higher molecular weight speciments. This may be due to a smaller number of chain entanglements and consequent chain slippage. In PMMA, whitening induced liquids seem to have a solubility parameter somewhat greater (2.5 ∼ 5.0) than that of PMMA. For PC, no consistent tendency is found.
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    Polyurethane-poly(methyl methacrylate) interpenetrating polymer networks: Some mechanical properties (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 394-398 
    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 mechanical behavior of polyurethane-poly(methyl methacrylate) interpenetrating polymer networks (PUR/PAc IPN's) was investigated. Stress-strain and impact resistance measurements were made on IPN's with a variable PUR content. The effect of the degree of crosslinking of each network on the mechanical properties was also studied. It appears that only the ultimate elongation varies largely upon changing the crosslink degree. The results are interpreted in terms of the contribution of each network to the mechanical behavior, but also by the interpenetration of both components and by the phase continuity of the PAc network.
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    URL: http://dx.doi.org/10.1002/pen.760230705
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    Plane strain fracture toughness of polyethylene pipe materials (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 404-411 
    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 plane strain fracture toughness of medium density polyethylene pipe materials has been investigated over a range of test temperatures and rates. Conditions are defined under which valid fracture toughness values can be obtained; at higher temperatures the material is notch-insensitive. Fracture surface morphology is described, and features are compared with predictions from the Dugdale model. The toughness derives from a band of fibrillar, drawn morphology associated with crack initiation or slow growth. The plane strain fracture toughness correlates with percent crystallinity according to the same relationship whether the crystallinity is varied by thermal treatment, comonomer content, or molecular weight.
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    Properties of phenolic fiber-reinforced polymers (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 776-778 
    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: Fibers made of phenol formaldehyde are relatively new to the market place and are currently manufactured in Japan. They have certain characteristics which make them attractive as a reinforcement for rubber, thermoplastics, and thermosets. This paper will discuss the properties of molded polypropylene thermoplastics as a function of fiber weight percent and surface treatment. It is shown that the elevated temperature properties are improved without sacrifice of low-temperature brittleness.
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    Phase relationships of rigid rod polymer/flexible coil polymer/solvent ternary systems (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 789-791 
    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: Phase diagrams of two types of rigid rod polymer/flexible coil polymer/methanesulfonic acid (MSA) ternary systems were determined by polarized optical microscopy at ambient conditions. The rigid rod polymer is a wholly aromatic high temperature resistant (no measurable Tg) poly (p-phenylenebenzobisthiazole) (PPBT). One of the flexible coil polymers is a wholly aromatic high temperature resistant poly (2,5′(6′) benzimidazole) (ABPBI), the other is a thermoplastic poly[2,2′ -(1-4-phenylene)-6,6′ -bis (3-phenyl-quinoxaline)] (PPQ) with Tg of 359°C. The solvent is methane-sulfonic acid (MSA). The experimentally determined critical concentration points, Ccr, are in excellent agreement with Flory's recent theory. Total phase segregation between the polymer pair in ternary solution was predicted and observed at C 〉 Ccr. Different decomposition mechanisms of phase separation were observed as a function of concentration.
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    Injection molding of thermotropic liquid crystal polymers (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 792-796 
    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: Thermotropic liquid crystal polymers consist of rod-like molecules and are often called “self reinforcing thermoplastics.” Their rheological behaviors as well as orientation development during processing are often very similar to those of short fiber-filled composites. Without reinforcement, the polymer shows superior mechanical properties to conventional glass fiber-reinforced engineering resins. The orientation distribution in the crosssection as well as flow patterns in the molded thermotropic polymers are clearly visible to the naked eye due to color differences. This makes it particularly convenient to study the orientation distribution as well as the flow patterns of packing, back flow, jetting, flow instabilities, and weld line formation in injection molding. This paper discusses physical properties of a typical ther motropic polymer and their relationship to mold filling process in the injection molding.
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    Effect of a diamine additive on the structure-property relationships of rim polyurethane elastomers (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 816-819 
    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: Structural and mechanical data have been compared for reaction injection molding (RIM) polyurethanes prepared from uretonimine-modified diphenylmethane 4,4′-diisocyanate (MDI), ethylene glycol (EG), and a polyol (a polyether; Mn ≃ 5000), in order to investigate the effect of addition of a small amount of a polyetherdiamine (PEDA; Mn ≃ 400) to the reaction mixture, A series of specimens containing 18 parts and 30 parts EG, with and without the diamine additive, were examined both as-prepared and after thermal annealing. The specimens were compared in terms of their x-ray crystallinity, elongation, flexural modulus, impact strength, and heat-sag behavior. All of the specimens showed evidence for crystalline hard segments, which are more abundant in the series containing 30 parts EG. The crystallinity is lowest in the as-prepared specimens without the PEDA additive, and is increased by annealing for 1 hour at 120°C. The as-prepared specimen with additive has a hard segment crystallinity similar to that of the annealed specimen without additive. These results correlate with the mechanical property data, which improve as a result of annealing and/or the use of a PEDA additive. It is argued that the use of the polyetherdiamine enhances the phase separation and facilitates hard segment crystallization, leading to better heat-sag behavior. It is significant that the unannealed/with PEDA and annealed/without PEDA specimens have similar properties. Use of PEDA additive improves the green strength and impact strength of molded parts.
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    Masthead (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983) 
    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.760231601
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    Deformation studies of polystyrene/poly(vinyl methyl ether) blends by mechanical-vibrational spectroscopy (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 861-868 
    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 have analyzed the deformation behavior of compatible and incompatible polystyrene (PS) and poly(vinyl methyl ether) (PVME) blends by a combination of mechanical and vibrational spectroscopy. Macroscopic properties and segmental orientation were found to be sensitive to molecular weight, strain rate, and temperature of measurement above the glass-transition temperature. Considerably different orientation functions were found for the PS and PVME components. For the experiments carried out above the Tg of the blends, the deformation behavior measured was consistent with expectations of a rubbery network.
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    Thermal, mechanical, and rheological behavior of blends of ultrahigh and normal-molecular-weight linear polyethylenes (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 888-894 
    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: Physical Blends of ultrahigh-molecular-weight linear polyethylene (UHMW LPE) and normal-molecular-weight linear polyethylene (NMW LPE) have been evaluated in terms of melt flow rate, tensile stress-strain behavior, heat of fusion, melting temperature, and crystallinity. The behavior of the blends is intermediate between that of the parent polymers; no synergistic effects are observed. The addition of small quantities of NMW LPE does not improve the flow behavior of UHMW LPE sufficiently to render it amenable to conventional melt processing.
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    Failure of rubber-modified plastic liners (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 560-566 
    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 analyze the failure phenomenon of plastic liners in freezers and refrigerators the mechanical properties of the freon blown polyurethane (PU) foam insulator material and the acrylonitrile-butadiene-styrene (ABS) plastic liner are determined. The properties considered essential for this problem are the elastic modulus, the tensile strength and the fracture toughness over the temperature range -40 to 20°C. By laminating a layer of the polyurethane foam to the ABS liner and depending on the test temperature brittle to semi-brittle fractures are promoted and the maximum load fracture toughness of the liner material is reduced. The reduction is more severe for notched bend than for single-edge notched tension specimens. Based on these mechanical properties plausible reasons for liner fractures are discussed.
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    Determination of time independent component of the complex modulus during cure of thermosetting systems (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 586-590 
    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 recent development suggests an approach to measure the equilibrium modulus through an impulse method. This paper is to report an attempt to apply such methods in measuring the changes of the equilibrium modulus of a thermosetting system during isothermal cures. Dynamic modulus changes were also measured and the results were correlated with that from the impulse method. At two different temperatures of cure, the equilibrium modulus values measured were very similar when the dynamic measurements showed tan δ = 1. At this point, it is not certain if the measured modulus is the real time independent portion of the elastic modulus, or contains the long relaxation time constant portion of the relaxation spectrum which appears to be pseudo-time independent at the time scale and the instrumental sensitivity of the present experimental set-up. This paper demonstrates the ease with which the impulse technique can be applied and suggests possible limitations or refinements.
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    Melt flow of polymer blends (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 602-609 
    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 production of polymer blends increases at a rate of about 13 percent/y. Most of the commercial blends are multiphase systems of complex morphology, determined by the thermodynamic properties of the components and the rheology. Since the diffusion rates are relatively low, the blends are seldom at equilibrium. In most cases, the blend products have properties imposed by the morphology, created by a particular combination of the thermal and deformational history. There are three main reasons for studying the melt flow of blends: optimization of the processing conditions, search for the appropriate means to generate the desired morphology, and the interest in the basic study of the rheology of these complex systems.In this paper the results published during the last five years are reviewed. The data for polymer blends are compared with those obtained for simpler model systems: liquid mixtures, emulsions, and polymer blends. From the rheological point of view, the blends are divided into three groups: those where viscosity shows positive deviation from the log-additivity rule, PDB, those where the opposite effect is observed, NDB, and the remaining mixed-behavior systems, PNDB. To PDB belong the miscible blends and those with strong inter-domain interactions. To NDB belong those where the interactions are weak. To PNDB belong the blends in which there is a concentration-dependent transition of structure. The shear dependent properties of blends are also discussed.
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    Engineering and molding properties of poly(vinyl chloride), acrylonitrile-butadiene-styrene and polyester blends (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 627-631 
    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: Polymer blends with varying amounts of poly(vinyl chloride) (PVC), acrylonitrile-butadiene-styrene (ABS) and polyester have been developed to produce parts with highly flexible, good impact strength, and flame retardant hinge properties. In the present work, the rheological and dynamic mechanical properties are balanced by changing the blend formulations. It is shown that blends morphology and rheology have greater impact on the dimensional stability and delamination at the surface of the molded hinge parts.
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    A comparison of miscible binary blend interaction parameters measured by different methods (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 676-681 
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    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: Miscible blends of the polyhydroxy ether of bisphenol-A, Phenoxy, with a series of aliphatic polyesters were studied using melting point depression analysis and sorption to obtain the Flory-Huggins polymer-polymer interaction parameter, B. The B values obtained from these measurements were found to agree well in sign, magnitude, and variation with ester repeat structure and to also agree well with B values measured calorimetrically for mixtures of low molecular weight compounds with structures which are analogous to those of the polymers. These comparisons suggest that the same mechanisms are responsible for the exothermic heats of mixing measured directly for the analog compounds and indirectly for the miscible polymer blends. For this general system, evidence is provided which suggests that hydrogen bond formation between the hydroxyl group on Phenoxy and the ester moiety is probably responsible for the exothermic interactions and polymer blend miscibility observed.
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    A survey of dual phase continuity and miscibility in interpenetrating polymer networks, making use of selective decrosslinking and dissolution of one component: Poly(n-butyl acrylate)/polystyrene (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 693-696 
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    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 sequential interpenetrating polymer network, IPN, may be defined as a combination of two polymers in network form, at least one of which was polymerized or crosslinked in the presence of the other. Two major problems of interest to sequential IPN's relate to phase continuity and extent of mixing within each phase. A first attempt to define the molar volume of a network is made in terms of the molar volume of the polymer between crosslinks. This permits a thermodynamic calculation of the changes in molecular mixing expected as a function of crosslink density. The experimental system was poly(n-butyl acrylate)/polystyrene IPN's, where the PnBA was crosslinked with acrylic acid anhydride. This last may be selectively hydrolyzed, forming a semi-IPN, and then the PnBA can be extracted. Scanning electron microscopy and dynamic mechanical spectroscopy were carried out at each stage.
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    Viscoelastic properties of polyamic acid solutions - precursors of polyimides (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 713-718 
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    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 rheology of polyamic acid (PAA) solutions, precursors of polyimides used in microelectronic device applications, has been investigated by dynamic (oscillatory) shear flow measurements. Frequency dependent storage and loss moduli and dynamic viscosity were measured in the frequency range 10-1 to 103 rad/s at 23°C. The storage modulus G′ (ω) and loss modulus G″ (ω) exhibited quadratic and linear dependence in frequency at low frequencies respectively, the viscoelastic fluid behavior commonly predicted for polymer solutions from many molecular theories. At high frequencies both dynamic moduli become proportional to ω2/3. The results show that PAA solutions are very high loss viscoelastic fluids, judging from the loss tangent values which far exceed unity. It is suggested that dynamic viscoelastic properties could be used to monitor the degree of imidization since there is a gradual change from viscoelastic fluids to soft viscoelastic solids to hard viscoelastic solids as PAA is converted to polyimides. Onset of non-Newtonian flow as shown on the frequency dependent dynamic viscosity was in the range 30 to 200 rad/s. The viscoelastic constants, zero-shear rate viscosity ηo and steady-state compliance Je0, where also determined from the dynamic data and compared to previous steady shear flow results.
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    Masthead (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983) 
    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.760231401
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    Thermal and rheological properties of blends of polystyrene and thermotropic liquid crystals (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 779-783 
    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 rheological and thermal properties of composites of polystyrene (PS) and two liquid crystalline low-molecular-weight additives have been studied. Both additives act as plasticizers as evidenced by decreases in the glass transition and the melt viscosity. In addition both are miscible with PS over a broad range of concentrations. Partial phase diagrams of the two systems are presented and discussed.
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    Solution processing and properties of molecular composite fibers and films (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 784-788 
    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: Experimental studies of fiber wet-spinning and solution processing of films of molecular composites are presented. The rigid rod polymer was poly (p-phenylenebenzobisthiazole) (PPBT) and the flexible polymers were poly (2,5(6′)-benzimidazole) (ABPBI) and poly (2,5(6′)-benzothiazole) (ABPBT). Effects of the flexible polymer molecular entanglements in solution on the processing are discussed. These fibers and films have very high modulus and strength, which improve upon heat treatment. The uniaxial modulus of highly oriented molecular composites follows the linear rule of mixtures.
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    High modulus/high strength polyethylene obtained by high-pressure injection molding (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 869-876 
    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: Increasing the nominal injection pressure up to 500 MP a improves the mechanical properties (modulus and strength) of injection-molded high-molecular-weight high-density polyethylene substantially. By a proper combination of barrel and mold temperature, the modulus of the molded parts (test bars) may be increased at least eight times compared to parts molded at 100 MPa. This improvement is partly due to the formation of high-strength crystalline modifications of the polyethylene induced by flow and pressure. The extent to which these structure modifications occur in the samples molded at various conditions has been determined by thermal analysis (DTA). When increasing the thickness of the samples, a sharp reduction of the modulus and strength was observed, even though the concentration of the crystalline high-strength phase was higher. An explanation of this effect in terms of the relaxation of the tie-molecules connecting the crystallites is suggested.
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    Rebound test to measure the strength of polymeric materials (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 902-906 
    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 this work it is shown that rebound experiments, carried out at low blow impact and by means of instrumented pendula, can be described in terms of the equation for a freely oscillating linear viscoelastic body with added mass. The experimental and calculated load-time curves are in very good agreement when the behavior of the material is linear viscoelastic; the assumptions made (transitory time shorter than rebound time, and negligible mechanical friction) are thus proved to be reasonable. The rebound test, which can be carried out on unnotched or notched specimens, allows one to obtain quickly and easily relevant material properties such as Young modulus or compliance, stored and dissipated energies, and the upper linear elastic limit at a testing speed not too far from that of impact testing.
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    Profile modification of resist patterns in optical lithography (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 925-930 
    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 is described to modify profiles of resist patterns in novolac and diazo-oxide containing systems. After patterning of the resist, two successive uniform flood exposures are given, one with deep UV (254 nm) at water-free conditions and the next with near UV (λ 〉 300 nm) at normal atmospheric conditions. The profile which results after development is vertical, concave or overhanging depending on flood exposure conditions and development processing. As the method includes a flood near UV exposure at atmospheric conditions the imagewise exposure energy can be reduced to approximately 35 percent of the normal value. Furthermore it gives also the possibility of using the resist as a deep UV resist. Another important implication is that standing wave effects are completely eliminated.
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    Mathematical modeling of the blow-molding process (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1075-1083 
    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 simulation of the blow-molding cycle has been developed by combining general conservation principles along with appropriate constitutive relations for the material. A model of the parison formation stage has been devised by considering the competing effects due to swell and drawdown. A more rigorous numerical analysis of parison formation is also discussed. A theoretical treatment of parison inflation is described for both inelastic and viscoelastic materials by assuming uniform radial growth, Comparisons are made with experimental data for all phases of the molding cycle. The mathematical model is in reasonable quantitative agreement with experimental results and is capable of elucidating the influence of material properties and process conditions on the dynamics and performance of the blow-molding process.
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    Editor's note (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1107-1107 
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    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
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    13C NMR characterization of intermolecular interactions for polymers. Part 3. Solvent effect on the blend compatibility of poly(vinyl methyl ether) and polystyrene (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1109-1116 
    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 solvent has an influence on the homogeneity of the poly(vinyl methyl ether)-polystyrene, PVME-PS blends Prepared by drying cosolutions. This influence has been analyzed in terms of the competition among polymer-polymer and polymer-solvent interactions. Model solutions have been prepared in which intermoleeular interactions correspond to the interactions in this blend and in some of the cosolutions. These interactions in the model solutions have been detected and identified by applying Rummens' method. The 13C NMR spectra have been determined for PVME and for styrene oligomer dissolved in n-alkanes, cyclohexane, diethyl ether, isopropyl methyl ether, diisopropyl ether, and chloroform, and for PVME dissolved in benzene, toluene, and cumene. The chemical shifts have been plotted against the parameter g2 = [(n22 - 1)/(n22 + 1)]2, where n2 is the refractive index of the solvent. If the structural segment represented by certain carbon and some solvent has an interaction that is stronger than dispersive, the chemical shift for this carbon will deviate from the line formed by its shifts in n-alkane solutions, these deviations indicate characters and intensities of the intermoleeular interactions. Results indicate that cyclohexane exhibits weak interactions with both of the polymers and does not interfere with their mutual interaction, leading to a compatible blend. Results also suggest that benzene and toluene interact in the PVME in the same manner as PS. This leads to a gradual increase of the number of polymer-polymer interactions as the concentration of the polymers is increased by solvent removal, resulting in a compatible blend. Chloroform apparently interacts more strongly with PVME than with PS but interacts strongly enough with both to restrict interaction among the two polymers. As the concentration of polymers in the cosolution is increased, PS forms a separate phase. This leads to an inhomogeneous blend when the solvent is evaporated.
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    Fracture toughness (KQ) testing with a mini-compact tension (CT) specimen (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1190-1198 
    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 testing method using the Rheometrics Mechanical Spectrometer as the loading instrument to measure the fracture toughness KQ, which is related to a specific sample geometry and dimensions (half-inch compact tension) is reported. The small sample size requirement makes it attractive to do fracture toughness testing on newly synthesized material for preliminary material study and comparison purposes. Commercially available epoxy resins were used to check the procedure at different temperatures (-150° to 250°C). An empirical crack length averaging method was used that appears to give constant KQ values independent of the a/W ratio values. The fracture surfaces were studied using scanning electron microscopy.
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    Studies of epoxy resin systems: Part A: A study of the origins of the secondary relaxations of epoxy resins by thermally stimulated depolarization (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1205-1212 
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    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 relaxation behavior of several epoxy resin systems, which have systematic structural differences, has been studied by the thermally stimulated discharge (TSD) technique. Two TSD peaks centered at about 115°K (β peak) and 185°K (β peak) were found for epoxy resins cured with a diamine. Structural change, either in the epoxy resin molecule or the amine molecule, did not seem to affect those two peaks. The TSD thermogram of the DGEBA (diglycidyl ether of disphenol A) epoxy resin part only showed a small new peak at 160°K instead of the ft peak at 185°K. This result, together with the fact that postcuring increased β peak height, leads to the conclusion that the ft peak is most likely due to the newly-created molecular segment during the curing reaction. The peak at 160°K was assigned to the epoxy group. This assignment was based on the fact that the 160°K peak of an epoxy homopolymer, which has fewer epoxy groups, was smaller than that of the parent DGEBA. The β and γ peaks were found to be of distributed characteristics, and the distribution of activation energy was studied by the partial heating method.
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    Masthead (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983) 
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    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.760230101
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    New techniques for the characterization of orientation in semicrystalline polymer moldings (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 257-260 
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    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 describes new techniques for evaluating orientation in polymer moldings. Injection moldings of isotactic polypropylene, a semicrystalline polymer, have been used to demonstrate the analytical procedures.
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    Parameter design model for corrugated tubing (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 285-292 
    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: It is of interest to produce plastic corrugated tubing as strong as possible with a minimum amount of material. Simultaneously, the tubing has to resist stretching, and maintain flexibility for transport purposes. To find the optimum profile geometry, two mathematical models were employed. One model was used to calculate the strength of the tubing per unit length and a second model was used to predict the elongation of corrugated tubing for a given load. Data was then generated for different profile configurations, and plotted for an optimum design procedure. The results showed that, while the wall thickness can be varied during production, the most critical parameter is the corrugation depth. The corrugation depth is fixed by the moldblock design, and the data presented can be used to obtain an optimum geometry.
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    Physical properties of high-pressure ethylene vinylacetate copolymers and their saponified derivatives (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 306-317 
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    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 physical properties of high-pressure ethylene vinylacetate (EVA) copolymers having an average melt index of 8.5 g/10 min and a mol% of VA less than 20 are studied. A comparison is made with the properties of their saponified derivatives, the ethylene vinylalcohol (EVAl) co- and ethylene vinylalcohol vinylacetate (EVAlVA) terpolymers. A melt-index effect is noted. Density, thermal, and mechanical properties of EVA copolymers are determined by the degree of crystallinity, which depends on the mol% VA and on the degree of alkyl shortchain branches. EVAlVA terpolymer properties depend on the residual mol% VA. EVAl copolymers proved to have some properties similar to low-density polyethylene. The hydrogen-bonding effect via hydroxyl groups was negligible for this level of vinylalcohol incorporation.
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    Masthead (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983) 
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    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.760230701
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    Laminar mixing of polymeric liquids; a brief review and recent theoretical developments (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 357-379 
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    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 work concerns itself with laminar mixing of viscous liquids. The primary focus is on mechanical mixing of immiscible fluids but mixing of diffusing and reacting fluids is also briefly considered. Operations such as thermal homogenization and reactive mixing usually not treated in the context of laminar mixing are also included here. The emphasis is on mixing of polymeric liquids and on basic experimentation and theory. Dispersion of solids, mechanisms of demixing (such as gradient coagulation), properties of mixtures, and the description of mixing equipment are not considered. There are no substantial reviews covering developments of theory and applications in laminar mixing in terms of a fundamental unifying theory and analyses relating operating variables to mixing quality. This review, although an attempt in this direction, is not self sufficient and cannot stand alone without recourse to the indicated references. The reader is assumed to have some familiarity with the literature on mixing. Thus, basic concepts are not explained but merely reviewed. Emphasis is given to recent theoretical developments; application examples are provided. The objective here is to condense results from several diverse sources, to present and extend recent developments, to point out the relation of the subject to seemingly unrelated work, and to suggest areas for further research.
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    Introductory remarks (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 649-649 
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    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.760231202
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    Hydrogen bonding in polymer systems (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 669-675 
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    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 importance of hydrogen bonding interactions in promoting polymer miscibility has been the subject of much recent investigation. In this study, we address the question of the effect of molecular size and geometry on the intensity of the hydrogen bonding interaction. To this end, the interaction of the functional group in various molecules with a variety of acid and base polymer matrices has been monitored using infrared spectroscopy. The “probes” used in this study each contained only one functional group per molecule to prevent intra-molecular association. The probes were acetone, di-n-hexyl ketone, 10-nonadecanone, cyclohexanone, cyclododecanone, isopropanol, 4-decanol, 10-nonadecanol, cyclohexanol, and cyclododecanol. The interactions of the base probes with poly-(vinyl chloride), poly(vinylidine fluoride), phenoxy, poly(styrene-co-allyl alcohol), and a variety of cellulosic polymers were studied. Acid probe interactions were measured in poly(pivalolactone), poly(butanediol-1,4-terephthalate), poly-(acetal), poly(∊-caprolactone), poly(vinyl methyl ether), poly(4-methoxy styrene) and poly(ethylene oxide). The effect of the presumably inert poly(styrene) and ethylene-propylene rubber matrices on the probe's functional group was studied for comparison.
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    Masthead (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983) 
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    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
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    Bulk copolymerization of styrene-acrylic esters: Some analysis and design considerations (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 719-725 
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    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 common framework for the analysis of styrene-acrylic ester systems has been developed by analyzing the pertinent kinetic information. This is shown to lead to a well defined strategy for the design of copolymerization reactors especially in the industrially relevant high conversion region. The existence of stable steady states and its influence on the system parameters has been illustrated for the case of a continuous stirred tank reactor (CSTR). A novel strategy of a CSTR operated with a recycle is proposed. This is shown to lead to an operation in the unique steady state with the added advantage of a high conversion and uniform copolymer composition. This would seem to be the first such analysis in the high conversion region.
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    Fiber fracture in reinforced thermoplastic processing (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 743-749 
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    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 length reduction of reinforcing fibers in short-fiber reinforced plastics during processing has been studied experimentally. It has been shown that fiber volume fraction, initial length, and initial state of dispersion have little effect on the final fiber length. In dilute suspension theory based on shearing flow conditions and fiber properties the flow stresses are found to be compatible with the experimental results and results which are found in the literature.
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    Dynamics of ion beam modification of polymer films (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 931-934 
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    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: Thin polymer films were irradiated in a high vacuum environment with energetic (∼2 MeV) ions. The emitted molecular species were studied with a quadrupole mass spectrometer during bombardment. The emitted species are predominantly small molecules. The efficiency of emission depends strongly upon the electronic energy loss of the incident ions in the film and, hence, upon the velocity and atomic number of the incident ion. The emission efficiency of all species decreases with increasing damage in the film. By pulsing the ion beam, the time dependence of irradiation induced emission of molecular species from the films has been studied. Emission delays of hundreds of milliseconds are observed in some cases. These delays are found to depend upon the emitted species as well as the host film and seem to be associated with diffusion of the species in the films.
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    Submicron patterns in substituted polystyrene resists by focused-ion-beam lithography (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 941-946 
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    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: Submicron lines in negative working, substituted polystyrene resists by focused-ion-beam lithography were demonstrated. These features were transferred into an underlying molybdenum layer by plasma etching using the resist as an etch mask, with the minimum continuous line having a width of 0.20 μm.
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    Evaluation of poly(allyl methacrylate)-co-(hydroxyethyl methacrylate) as negative electron-beam resist (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 963-967 
    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: Poly(allyl methacrylate)-co-(hydroxyethyl methacrylate) has been evaluated as a high-sensitivity, high-resolution, high temperature-resistant negative electron resist. The effects of molecular weight and polydispersity of the copolymer on its lithographic performance as an E-beam resist were studied. The sensitivity of the copolymer is nearly constant in the weight-average-molecular-weight range of 50,000 to 75,000, and it gradually decreases with a decrease in molecular weight. As expected for a negative resist, the resist contrast increases as the polydispersity is decreased. The sensitivity curve shape of the polymer was independent of the prebake temperature, which varied from 70 to 110°C, and of the various developers used. The exposed coating requires vacuum curing for image optimization. Resolution of 0.5 μm line/space pairs was obtained from a 0.6 μm thick resist by exposing the resist to 10 keV electrons with either a raster-scan-type or vector-scan-type electron-beam exposure machine. After postbaking at 170°C, the resist had good resistance to both chemical etching and dry etching. The plasma-etch resistance was about twice that of PMMA.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760231709
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    Batch polymerization of styrene-optimal temperature historiesThis paper was presented at the 1980 Annual Meeting, American Institute of Chemical Engineers, Chicago, III. (November 1980). (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1-8 
    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: Optimal temperature histories for the batch thermal polymerization of styrene are determined using Pontryagin's maximum principle. The theoretical predictions are compared with experimental measurements of conversion and molecular weight distribution. The excellent agreement suggests policy improvements in batch radical chain growth polymerizations.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220102
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    Masthead (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982) 
    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.760220201
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    Introduction (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 57-57 
    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.760220202
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    Polymer compatibility with and without a solvent (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 64-73 
    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 qualitative review of the thermodynamics of polymer systems will be given in terms of three contributions: positional (or combinatorial) entropy, an “international” term and a free volume term. From this one finds that a simple polymer-solvent system phase separates on lowering T to an Upper Critical Solution Temperature (UCST) or raising it to Lower Critical Solution Temperature (LCST), To achieve miscibility of two polymers of high molecular weight, one requires a “specific” interaction, usually a weak charge-transfer complex or a hydrogen bond. Phase separation takes place on raising the temperature to an LCST. These various UCST and LCST are predicted semi-quantitative by the Prigogine-Flory theory. When a solvent is added to two miscible polymers, a new type of phase separation appears since there is an effect of any difference in the strengths of the two polymer-solvent interactions. Phase separation may easily occur in the ternary system where there is none in the three binary systems, and examples will be given. In the case of two highly-attractive polymers in a solvent, a quite different phase separation occurs, sometimes called complex coacervation. A simple Flory-Huggins type theory predicts these phenomena in ternary systems.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220204
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    High modulus semi-crystalline polymers by solid state rolling (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 27-33 
    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: Solid state rolling of semi-crystalline polymers is shown to be an effective method of producing high strength, high modulus tape at acceptable production rates. High density polyethylene tape was produced having a tensile strength exceeding 300 MPa and a tensile modulus of 8.7 GPa at production rates exceeding 8 m/min. A significant factor in producing highly oriented tape by the rolling process is roll temperature. Increasing the roll temperature from 25°C to 125°C not only increases the maximum extent of orientation achievable, but increases the mechanical properties at a given degree of thickness reduction. Internal frictional heat development limited the maximum thickness reduction ratio of polypropylene to 6.6:1. This reduction was reached by rolling at 150°C. The resultant tape had a tensile modulus of 5.1 GPa and a tensile strength of 300 MPa.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220105
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    Residual stresses in polymers I: The effect of thermal historyThe availability of appropriate illustrations has led to publication in this journal of Part II (Vol. 21, NO. 15, page 997) p or to this Part I. (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 40-47 
    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 distribution of residual stresses in quenched modified poly(phenylene oxide) (PPO) specimens was investigated. Quenching was carried out from temperature level above Tg to various temperatures below Tg. As expected, compressive stresses were measured at the surface layers while tensile stresses were in the inner layers. The ratio between the tensile and compressive stresses varied, depending on the thermal history. The level of residual surface stresses was found to depend on both the total temperature difference during cooling and the initial specimen temperature. At constant initial temperature the surface stresses are proportional to the total temperature difference, whereas, at constant final temperature the surface stresses are inversely proportional to the total temperature difference. An empirical correlation describing the surface stresses as a function of thermal history has been suggested. The differences between present theories and experimental data are discussed. emphasizing the apparent discrepancy regarding the influence of initial temperature above Tg on the level of residual stresses.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220107
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    Kinetics of a sterically hindered amine-cured epoxy resin system (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 166-171 
    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: Fourier transform infrared spectroscopy (FT-IR) and torsional braid analysis (TBA) were used to study the reaction of an epoxy resin system cured with a sterically hindered amine. Isothermal torsional braid analysis showed the apparent activation energy to be approximately 42 kJ/mol. The reaction kinetics were also considered from the unreacted freshly mixed condition and a partially reacted “B-staged” condition using infrared spectroscopy, The B-staged condition is unreactive and stable at room temperature due to the quenching of the primary amine reaction by the glassy structure and the steric hindrance of the secondary amine reaction. Apparent activation energies for these two conditions were found to be 49.4 kJ/mol and 49.0 kJ/mol respectively. The storage life at room temperature of the B-staged resin system is predicted to be at least three months based on extrapolation of the experimental kinetic data.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220306
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    A Note on the prediction of polyethylene melt rheological properties from molecular weight distribution data obtained by gel permeation chromatography (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 53-55 
    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 the present study, a modification of the method previously presented by the authors for predicting rheological properties of linear polyethylene melts from gel permeation chromatography (GPC) data is presented. The modification involves independent values of the zero shear viscosities for melts rather than generating these values internally. The comparison between the experimental zero shear viscosity values and those calculated from GPC data is shown to be very good.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760220109
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    Graft copolymerization of vinyl chloride onto ethylene propylene rubber (EPR) and ethylene propylenediene monomer (EPDM) by bulk processPresented at the 180th National Meeting, American Chemical Society, August 1980. (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 48-52 
    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: Vinyl chloride was graft copolymerized on ethylene propylene rubber (EPR) and ethylene propylene diene-monomer rubber (EPDM) by a bulk process to give a multi-component end product consisting of three components and two phases. The reaction system forms a pseudo-emulsion at an early stage of reaction where the phase morphology of graft poly(vinyl chloride) (PVC) is determined. The formation of pseudo-emulsion was confirmed visually, by the particle size of PVC prepared in the presence of rubber and by the phase morphology of rub be r-g-PVC which is similar to that from an aqueous emulsion system. The degree of graft depends on the unsaturation of the rubber used as backbone. The amount of grafted EPR does not exceed 60 percent of the initial rubber; however, the amount of grafted EPDM is always higher than 60 percent of the initial rubber and increases further as the unsaturation increases. The degree of graft was found to be independent of the type of radical initiator used indicating that the abstraction of hydrogen from the rubber is carried out by the PVC radical to generate the grafting point. The graft PVC shows considerably improved processability which is equivalent to that of commercial vinyl chloride copolymers containing small amounts of propylene. It also shows dramatically improved impact strength which ranges from ten to twenty times that of PVC homopolymers.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220108
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    Temperature dependence of the viscoelastic shift factor in ionomersBased on presented at the 63rd Annual Conference of the Chemical Institute of Canada, Ottawa, Ontario, June 8-1, 1980. (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 81-87 
    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 temperature dependence of log a of poly(styrene -co- sodium methacrylate) was analyzed by means of the relation based on the free volume and the hole theories of liquids. For the near-Tg region the relation becomes a single parameter equation of T/Tg. The analysis revealed a transition in flow pattein at TT associated with disintegration of the ion multi plets. The Tt-transition was previously detected in other theological functions, viz, relaxation modulus, mechanical and dielectric tan δ plots.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220206
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    Melt rheology of polymer blends (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 96-114 
    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 rheological behavior of polymer blends is compared with that reported for emulsions, block polymers and homologous polymer blends. It has been shown that the properties of polymer alloys frequently differ from those of these “model” systems - the principal difference being the lowering of at least one rheological function below the value predicted In the log-additivity rule. Primarily, the most recent (post 1977) results are reviewed. The data obtained by the authors on the flow of poly(ethylene terephthalate)/Polyamide-6,6 are discussed in detail.
    Additional Material: 30 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220211
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    Discussion on terminology (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 137-139 
    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.760220215
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    Masthead (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982) 
    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.760220301
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    The principles of pipe-line design for molten poly(ethylene terephthalate) (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 141-146 
    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 of molten poly(ethylene terephthalate) in pipes is discussed. The considerations made are based on the results of previous investigations by the authors, concerning the rheological behavior of the melt which exhibits thermal degradation. A procedure is proposed which enables the design of a pipe-line system for the distribution of molten, spinnable poly(ethylene terephthalate) in a fiber plant to be made.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220302
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    Shear-induced anisotropy in thermal conductivity of a polyethylene melt (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 154-157 
    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 rotating concentric-cylinder thermal conductivity cell for polymer liquids is described. Thermal conductivity can be measured at temperatures approaching 200°C and at strain rates up to 400 s-1, The transient heat flux probe (with inner cylinder as heat source and temperature probe) method is used to permit the separation of the viscous heating effect from the probe heating effect.A polyethylene melt was studied and showed that at 50 s-1, a 2 percent increase in thermal conductivity occurs, followed by a gradual decrease until a value 10 percent less than the no-shear thermal conductivity was found at 400 s-1. This effect is due to molecular orientation.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760220304
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