ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Chemical Engineering  (2,596)
  • 1980-1984  (2,596)
  • 1
    Electronic Resource
    Electronic Resource
    Zero migration of monomers in glassy polymers: A possible artifact of thermal depolymerization (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 473-488 
    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: Efforts to remove traces of monomers contained in polymers by stripping with steam have resulted in reports that a small concentration of monomer is inextractable, or “locked-in,” the polymer. Any concomitant depolymerization to monomer and diffusive elution of the formed monomer would, in the steady state, result in a constant concentration of monomer within the confines of the polymer. If only the polymer phase were sampled and depolymerization were ignored, this result could be interpreted as an apparent “zero migration” level of monomer. A model that describes the coupled processes of depolymerization and diffusion is presented; predictions and estimates of an apparent “zero-migration” concentration are offered for various polymer/monomer systems considering a variety of kinetic schemes. The effects of temperature, geometry, and sample size on the transient and apparent steady-state, residual-weight fraction of monomer in the polymer are considered. Also, the weight fraction of monomer, neglecting diffusive elution, is estimated for comparison with the steady-state weight fractions calculated for the case in which diffusive elution significantly lowers the residual steady-state monomer level. The results predicted by the model presented are compared with experimental data reported in the literature. Transient approaches to the steady state are included in the model analysis. The steady-state monomer concentrations predicted for polystyrene and poly(acrylonitrile) at 100°C vary from 0.0001 ppm to 100 ppm as the diameter of the respective polymeric spheres varies between 0.5 μ and 500 μ. The predicted steady-state concentrations for vinyl chloride monomer in poly(vinyl chloride) are, under comparable conditions, seven orders of magnitude lower, reflecting the extraordinarily small tendency of polyvinyl chloride to degrade to monomer.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760230902
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    X-ray photochemistry: ω-Chloro olefin sulfones (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 957-962 
    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: To be efficacious as an x-ray resist, a material must efficiently undergo a desirable chemical change upon being irradiated with x-rays. The probability of such a change taking place is given by the product of the fractional x-ray absorption and the “inherent sensitivity,” which we define as the yield per unit energy absorbed. Increasing the absorption of the polymer, as, for example, by chlorinating an olefin sulfone thereby increasing the absorption at wavelengths just below the chlorine absorption edge will result in improved usefulness if, and only if, this increased energy absorbed can be used by the polymer to enhance the desired chemical reaction. The “usefulness” of chlorinating is thus dependent on the efficiency of intramolecular energy transfer. We have studied the efficiency of this transfer by monitoring the loss of SO2 from the main-chain backbone as a function of absorbed x-ray energy, using x-ray wavelengths both abov and below the chlorine absorption edge. The polymers studied were 1-olefin sulfones, with and without the chlorine atom in the ω-position. Through the use of this series of polymers it was hoped to observe an effect due to the changing separation of the chlorine atom from the backbone. The experiments indicate that (a) the inherent sensitivity is independent of irradiating wavelength, for both the chlorine-containing and the non-chlorine-containing polymers; (b) the hexene polymers are considerably more sensitive than the lower members of the series (which exhibit a sensitivity which is approximately independent of the side chain length); and (c) the chlorine-containing polymers are less sensitive than the non-chlorine-containing species. At this time the explanation for these observations is speculative.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760231708
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Wrong-way behavior of packed-bed reactors: 1. The pseudo-homogeneous model (1981)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 27 (1981), S. 234-246 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A sudden reduction in the feed temperature to a packed-bed reactor leads to a transient temperature rise, which is referred to as the wrong-way behavior. A pseudo-homogeneous plug-flow model is used to analyze the structure of this transient behavior. The key parameters which determine the magnitude of this response are the dimensionless adiabatic temperature rise, activation energy, heat transfer capacity, coolant temperature, magnitude of temperature drop and length of the reactor. A simple expression is derived for predicing the maximum transient temperature rise.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690270210
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Wood fibers as reinforcing fillers for polyolefins (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1166-1171 
    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: Wood pulp fibers possess strength and modulus properties which compare favorably with glass fibers when the differences in fiber densities are considered. Softwood pulp fibers with fiber aspect ratios near 100 are readily dispersed into high-density polyethylene or isotactic polypropylene with the aid of carboxyic dispersing agents to form mixtures containing 50 weight-percent wood pulp which can be readily injection molded. The mechanical properties of the molded specimens were similar for all types of pulp including Kraft (bleached and unbleached), mechanical and chemical-mechanical pulps, waste pulps, and reclaim newspapers. Comparisons of the stiffness/weight efficiencies revealed that pulp composites equal or exceed the stiffness of most traditional materials of construction including steel, aluminum, glass-fiber composites, and talefilled polyolefins, while retaining a major material cost advantage. The measured strength values of the pulp composites were less than the theoretically predicted values due to the presence of voids created by the formation of volatiles during processing. Mechanical pulps which were available in dry form were preferred because of lower cost and ease of handling. Wood fibers are non-abrasive so that relatively large concentrations may be incorporated into polyolefins without causing serious machine wear during mixing and fabrication.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241504
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Weld line structures and properties in injection molded polypropylene (1981)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 21 (1981), S. 1149-1155 
    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: Weld regions are formed wherever polymer flow fronts meet. The present study examines the effects of melt temperature, mold temperature, mold cooling conditions, injection speed and annealing on the tensile properties and morphological structure of weld regions in four commercially available polypropylene resins. One of the resins contained nucleation particles. Scanning electron micrographs of the weld region revealed a wide range of morphologies from very strong welds which formed part of a stable neck to brittle failures at low elongation caused by the presence of large nucleation particles in the weld region. The melt temperature, mold temperature, and annealing had the greatest effect on the weld region's tensile properties.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760211706
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Weather effects on ammonium storage (1982)
    New York, NY : Wiley-Blackwell
    Plant/Operations Progress 1 (1982), S. 107-113 
    Details
    ISSN: 0278-4513
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prsb.720010209
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Ways of poly (vinyl chloride) stabilization (1980)
    Brookfield, Conn. : Wiley-Blackwell
    Journal of Vinyl and Additive Technology 2 (1980), S. 141-151 
    Details
    ISSN: 0193-7197
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Main results of research on poly (vinyl chloride) (PVC) stabilization are discussed. Stabilization is viewed from the standpoint of the modern notions of the reasons for PVC low thermal stability, the complicated nature of its dehydrochlorination, and the kinetics of its degradation. The internal unsaturated oxygen-containing groups of ∼C(O)—CH=CH—CHCl∼ type are regarded as the main source of the polymer instability. Typical processes resulting in PVC stabilization, such as the substitution of labile chlorine atoms and the destruction of initial active sites during reactions with various chemical agents, as well as the kinetic aspects of stabilizers' effect on HCl elimination and PVC macromolecules crosslinkage are considered. The influence of additives on the polymer coloration is estimated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/vnl.730020304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Waterborne coatings: Emulsion and water-soluble paints by Charles R. Martens, Van Nostrand Reinhold, october 1980, 316 pages, $22.50 (1981)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 27 (1981), S. 526-526 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690270330
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Water-soluble copolymers VIII. Synthesis and dilute solution rheological studies of dextran-g-poly(acrylamide-co-sodium acrylates) (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 163-168 
    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: Dextran-g-poly(acrylamide-co-sodium acrylates) were prepared by partial hydrolysis of dextran-g-poly(acrylamides) with controlled numbers and lengths of grafted chains. This hydrolysis route proved to be more effective than Ce(IV)-induced cografting of acrylamide and sodium acrylate comonomers onto dextran in producing the desired graft-copolymer structures. The resulting copolymers were characterized and the effects of composition, temperature, ionic strength, and shear rate on dilute solution rheological properties were studied.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240302
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Water vapor transport in an epoxy resin based on TGMDA and DICY (1980)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 20 (1980), S. 310-314 
    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: Water uptake has been measured in an epoxy resin based on tetraglycidylmethylenedianiline curved with dicyanidamide. The curing behavior of this system as elucidated by differential scanning calorimetry and Fourier transform infrared is complex. Based upon this information we selected curing temperatures and times in addition to the “standard” cure. The kinetics of the sorption of water by the materials which have undergone the standard cure indicate that the two modes of sorption are involved at high humidity and only a single mode at lower humidity (as seen by changes in the slope of the log Mt vs log t plots). The kinetics of the sorption in the resins which have undergone post cure at higher temperatures also indicate two or more modes of sorption at high humidities. However the slopes of the log Mt vs log t plots differ from those for the resin with standard cure. Subsequent sorption/desorption cycles on the standard cure resin showed marked increases in the initial sorption rate as well as changes in mode, suggesting that irreversible changes in the resin had occurred.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760200416
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...