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  • 1
    Electronic Resource
    Electronic Resource
    A cooperative molecular weight distribution test (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 269-282 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The development of gel permeation chromatography (GPC) has provided a convenient tool for the rapid determination of molecular weight distribution. The question has arisen as to the suitability of the method for specification purposes. The present work, suggested by the Naval Air Systems Command, represents an attempt to assess the precision of the method through a series of tests carried out by a number of laboratories using identical procedures on the same samples. Ten laboratories agreed to take part. Naval Ordnance Station, Indian Head, worked out standard conditions for operation of the chromatograph, for calibration of the columns, and for analysis of the GPC curves. Two samples of polystyrene were used by the various organizations for calibration of their instruments. Number-average molecular weight, heterogeneity index, and cumulative molecular weight distribution curves were determined on four samples of carboxyl-terminated polybutadiene (CTPB) and two samples of hydroxyl-terminated polybutadiene (HTPB), all unidentified except by letter code. All laboratories used identical directions for setting up CTPB and HTPB calibration curves which were based on curves determined from vapor-pressure osmometer molecular weights and GPC count numbers of fractionated material. Variation among the different laboratories was 0.15 in heterogeneity index, and a maximum of 1200 in molecular weight provided one aberrant set of values was eliminated. The six samples had heterogeneity indices from 1.15 to 1.54, while molecular weight varied from approximately 3000 to 6000. The average coefficient of variation of the molecular weight values was 6.2 ± 0.7%, which is quite acceptable. Variation in heterogeneity index was too great for specification purposes when considered among the different laboratories, but may be sufficiently good when measured by any one laboratory.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070170121
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  • 2
    Electronic Resource
    Electronic Resource
    Dispersion in gel permeation chromatography. A rapid numerical solution to Tung's integral equation (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 1479-1492 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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 rapid iteration method has been developed to correct the molecular weight averages calculated from raw GPC data for dispersion. Though simple in its performance, it covers the general case that the instrumental spreading characteristics (Tung's resolution factor h) depend on the elution volume. Moreover, it is irrelevant whether the calibration curve, being the logarithmic plot of the molecular weight versus the elution volume, is linear or not. The method has been applied to a number of well-characterized polystyrene mixtures and yields molecular weight averages which agree with those predicted theoretically. The effect of asymmetry exerted by the dispersion on both molecular weight averages M̄n and M̄w is also discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150615
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  • 3
    Electronic Resource
    Electronic Resource
    Liquid transport through membranes prepared by grafting of polar monomers onto poly(tetrafluoroethylene) films. I. Some fractionations of liquid mixtures by pervaporation (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1061-1076 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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 separation of various liquid mixtures including systems of chloroform-hydrocarbons or ethyl ether, water-alcohols and water-nucleophilic organic solvents have been investigated by the pervaporation technique. Membranes were obtained by grafting Lewis base onto poly(tetrafluoroethylene) (PTFE) films. The PTFE backbone has been chosen for its mechanical and chemical resistance. N-Vinylpyrrolidone and 4-vinylpyridine were selected because of their great affinity for the electrophilic compounds. In all cases, the compound which has the greatest affinity for the membrane pervaporates selectively through modified PTFE films. Selectivity and rates were studied. It is concluded that because selectivity is very important, total separation of different mixtures is possible at a good yield, with a faster rate when the temperature is increased or the thickness of the membrane is decreased.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160502
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  • 4
    Electronic Resource
    Electronic Resource
    Liquid transport through membranes prepared by grafting of polar monomers onto poly(tetrafluoroethylene) films. II. Some factors determining pervaporation rate and selectivity (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 351-364 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of some factors including temperature, pressure, film thickness, and grafting ratio on the fractionation of binary liquid mixtures has been investigated by pervaporation through poly(tetrafluoroethylene) films grafted with N-vinylpyrrolidone or 4-vinylpyridine. The purpose was to estimate the best conditions in which the pervaporation process must be carried out. It was concluded that the pervaporation rate is increased at roughly constant selectivity when the temperature of the liquid charge is higher or when the downstream vapor pressure or the film thickness are decreased. A pressure higher than 1 atmosphere above the liquid does not increase the rate. When the grafting ratio is increased, the rate shows a maximum, and for particular conditions, the selectivity becomes much higher.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180204
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  • 5
    Electronic Resource
    Electronic Resource
    Surface morphology of polystyrene fractured in liquids. II (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 857-865 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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: Polystyrene has been fractured in tension at two temperatures in n-heptane and n-propanol and the fracture surfaces studied by optical and scanning electron microscopy. The test temperatures were selected such as to be approximately 20°C above and below the temperatures at which it was expected1 that a glass-to-rubber transition would occur in the solvent-penetrated craze material. It was found that features of the fracture process and also structure of the fracture surfaces were different at the two temperatures. These changes have been interpreted in terms of a Tg occurring in the craze material.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180320
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  • 6
    Electronic Resource
    Electronic Resource
    The alkaline hydrolysis of methyl methacrylate/isoprene copolymers. 3. Direct detection of the hydrolysed units (1972)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 153 (1972), S. 181-188 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Bromierung von Methylmethacrylat/Isopren-Copolymeren führt zur Bildung von γ-Lactonringen zwischen den benachbarten Methacrylat- und Isopreneinheiten. Die maximal erreichten Verseifungsgrade der Methacrylateinheiten in den bromierten Copolymeren sind geringer als die in den nicht behandelten Proben. Diese Tatsache erhärtet  -  gemeinsam mit anderen Erkenntnissen  -  die Schlußfolgerungen über die Verseifung, die in Teil 1 gezogen wurden.
    Notes: Bromination of methyl methacrylate/isoprene copolymers leads to the formation of γ-lactone rings between adjacent methacrylate and isoprene units. The limiting degrees of hydrolysis of the methacrylate units in the brominated copolymers are less than those in the untreated samples. This, together with other evidence, provides support for the conclusions about the hydrolysis reached in Part 1.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1972.021530115
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  • 7
    Electronic Resource
    Electronic Resource
    Breaking energies of a nylon series subjected to high-speed transverse impactThe material in this paper was presented at the Eighth Annual PIA Research Conference at Stevens Institute of Technology, Hoboken, N. J. on 5 November 1970. (1972)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 12 (1972), S. 41-47 
    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: In a study of the transient behavior of a series of nylon 6/6 yarns differing systematically in mechanical properties, the effects of high-speed, transverse missile impact upon yarn specimens were observed by high-speed photography. The loss in missile kinetic energy was determined directly from the reduction in missile velocity and was studied as a function of yarn tenacity and missile impact velocity. The shape of the missile energy loss curves was due to the partition of missile energy into yarn kinetic energy and yarn strain energy. The missile energy losses and yarn dynamic breaking strains were compared to static breaking energies and breaking strains for these yarns. The observed trends are discussed in terms of the differing yarn tenacities and test rates.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760120107
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  • 8
    Electronic Resource
    Electronic Resource
    Measurement of oxidation stability of polyolefins by thermal analysis (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 415-421 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Differential thermal analysis (DTA) is well known for measuring temperatures and heats of physical and chemical transitions in materials. Recent development work on improved stabilization systems for polyolefin wire insulations has required fast procedures for measuring the performance of stabilization systems. Isothermal DTA procedures have been developed into routine tools for measuring stability of polyolefins by determining the oxidative induction time at elevated temperatures.Oxidative induction time has been used to study the stability of polyethylene and polypropylene in raw material form and on wire. The dependence on temperature and antioxidant concentration have been measured. Effects of oxidation catalysts, catalyst deactivators and various environmental exposures are readily observed. Techniques and apparatus have been developed for simultaneous testing of a multiplicity of samples, providing for economical large scale use of the method.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130604
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  • 9
    Electronic Resource
    Electronic Resource
    Photoreactive polymers. IV. The synthesis and characterization of photocrosslinkable polysulfonates (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 513-518 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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 of new light-sensitive polysulfonate copolymers have been prepared by the interfacial polycondensation of mixed bisphenols and aromatic disulfonyl chlorides. The light-sensitivity bisphenols contain the styryl ketone group. These polymers exhibit good light sensitivity, and upon exposure to light they crosslink and harden to give alkali- and acid-resistant materials which are useful in photoresist applications.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150301
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  • 10
    Electronic Resource
    Electronic Resource
    Cleavage fracture of two polystyrenes (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 2211-2218 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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: Suspension and bulk-polymerized commercial polystyrenes have been fractured by cleavage and the resulting surfaces examined by optical and scanning electron microscopy. The method of styrene polymerization was found to influence the initiation and propagation of fracture, probably owing to the differing amounts of insoluble impurities remaining in the polymer. Various new aspects of the fracture morphology are described, and measurements of craze thickness by scanning electron microscopy are compared with values calculated from optical interference fringes.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180727
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