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  • Polymer and Materials Science  (633)
  • 1965-1969  (633)
  • 1
    Electronic Resource
    Electronic Resource
    Temperature dependence of photoelastic properties of crosslinked amorphous polyethylenes (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1183-1202 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Crosslinked samples of polyethylene were prepared by electron irradiation of both high- and low-density polymers in the crystalline state. A further crosslinked sample was obtained by curing a high-density polyethylene by reaction with dicumyl peroxide at 180°C. The stress-strain-birefringenece relations were obtained on specimens cut from these samples at temperatures between 130 and 250°C. All samples showed a substantial decrease in stress-optical coefficient with increasing degree of crosslinking and with increasing temperature. The stress-optical properties at each temperature were extrapolated to zero degree of crosslinking to give quantities characteristic of the Gaussian network. Comparison of these properties with the theory of networks of rotational isomeric chains with both independent and interdependent rotation allows estimates to be obtained for (1) the trans-gauche energy differences in rotation around skeletal bonds and (2) the difference in principal optical polarizabilities for the CH2 group in the elastomeric state. This latter quantity is shown to be more nearly given by Denbigh's than by Bunn and Daubeny's bond polarizability values.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060611
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  • 2
    Electronic Resource
    Electronic Resource
    Correlations between blood compatibility and heparin adsorptivity for an impermeable isotropic pyrolytic carbon (1969)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 3 (1969), S. 497-528 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The influences of conditioning treatments and surface topography on the heparin adsorptivity and the thromboresistance of a high-strength, impermeable, isotropic, pyrolytic carbon were investigated. The results of the adsorption studies indicate that the adsorption of heparin on such carbon surfaces is near the amount required for monolayer formation. The adsorbed heparin is rapidly elutriated in plasma. The heparin adsorption is not enhanced by a pretreatment with benzalkonium chloride. There was no relationship between the amount of heparin adsorbed on these materials and their compatibility with blood. Polishing, for example, which reduced heparin adsorption, enhanced the tromboresistance of these carbons, and while chemisorption of oxygen markedly reduced their thromboresistance, it did not influence the amount of heparin that could be adsorbed. In vivo tests showed that polished and outgassed, impermeable isotropic carbons deposited at low temperatures were significantly thromboresistant without the exogenous application of heparin. Examples of applications of these new materials in experimental valves are presented.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820030311
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  • 3
    Electronic Resource
    Electronic Resource
    γ-Irradiation of poly(ethylene terephthalate). I. Yields of gas and carboxyl groupsPaper presented at the 148th Meeting, American Chemical Society, Chicago, September 1964. (1966)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 4 (1966), S. 613-622 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(ethylene terephthalate) was exposed in vacuo γ-radiation from a Co60 source at a dose rate of 0.02 Mrad/min., and an ambient temperature of 47°C. Gaseous products were analyzed in a mass spectrometer and carboxyl groups estimated by titration with NaOH and by infrared analysis. Initial G values were —COOH = 0.77, CO2 = 0.17, CO = 0.11, H2 = 0.015, and CH4 = 0.003. All these values decreased markedly with increasing dose except G(CO)2, which, roughly, was maintained up to 5000 Mrad. It was considered whether the dependence on dose of the yields of the major reaction products could be accounted for by the following set of first-order reactions: It was found that the rate of formation of —COOH groups at low doses was much too high to fit this simple reaction scheme. However, a better fit was obtained over a range of higher doses (ca. 100-5000 Mrad). A final conclusion could not be reached concerning the validity of the above reaction scheme.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1966.150040315
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  • 4
    Electronic Resource
    Electronic Resource
    19F NMR of nitroso rubber copolymer (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 6 (1968), S. 181-183 
    Details
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.110060305
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  • 5
    Electronic Resource
    Electronic Resource
    Endgroup modification of unsaturated polyesters. Effect on chemical resistance (1965)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 1681-1700 
    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: Endgroups of unsaturated polyesters formulated with mole ratios of 2/1/3 and 1/1/2 isophthalic acid/maleic anhydride/propylene glycol were modified. Carboxylic acid content was effectively reduced by esterification with alcohols or epoxides, amidation with phenyl isocyanate, or neutralization with amines. Hydroxyl content was reduced by esterification with acids or anhydrides and urethane formation with phenyl isocyanate. Chemical resistance was determined by measuring the decrease in flexural strength and modulus with exposure to 10% solutions of sodium hydroxide and sulfuric acid at 82°C. A 2-week test using the medium chemical-resistant 2/1/3 polyester indicated that any modification which decreased the carboxylic acid content improved chemical resistance. Modifications which increased or decreased the hydroxyl content had no significant effect in the 2-week tests; however, decrease of hydroxyl content appeared important in 6-month exposure tests. The 1/1/2 resins which have high initial chemical resistance had poorer chemical resistance after endgroup modification than the unmodified 1/1/2 resin, with the exception of the phenyl isocyanate-modified product which was equal to the unmodified resin. Water (0.8%) and xylene (0.1%) had no effect on chemical resistance. However, larger amounts of residual solvent were disadvantageous.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1965.070090507
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  • 6
    Electronic Resource
    Electronic Resource
    Changes in the reactivity of functional groups during polyesterification: A new approach to polymerization in fatty-acid-modified polyesters (alkyd resins) (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 1593-1602 
    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: Gel-point calculations based on the theory of polyesterification proposed by Flory do not agree with the experimental values even when Bobalek's concept of gel point as the first formation of infinite molecules (microgel) is used. Resins covering the range 30-60% oil length were prepared and examined by electron microscopy for the presence of microgel particles. The extent of reaction at which microgel forms is discussed in relation to the concept of equal reactivity. The conditions necessary for the formation of microgel particles and the significance of these observations to the basic assumptions used in developing the theory of polyesterification are discussed.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070110820
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of molecular weight distribution and branching on rheological parameters of polyethylene melts. Part II. Fractions and blendsPresented at the 145th National Meeting of the American Chemical Society, New New York, N. Y., September 1963. (1965)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 767-776 
    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: Studies of the rheological properties of fractions of linear and branched polyethylenes have shown that the melt recovery of linear polyethylene fractions is very small and independent of molecular weight over a wide range. Fractions containing high degrees of long-chain branching, on the other hand, have high melt recoveries. The melt recovery of a fraction can therefore be used as an index of long-chain branching. Alternatively, if no long-chain branching is present, the melt recovery is a unique function of the molecular weight distribution. This effect is illustrated by blends of fractions. The log of the critical shear rate is a linear function of the log melt viscosity of the fraction for both linear and branched polyethylenes. This would indicate that the critical shear rate of polydisperse samples would depend primarily on the weight-average of Z-average molecular weight of the polymer. This is confirmed by previous studies on polydisperse samples. It also appears that critical shear rate is highly dependent on the homogeneity of the sample. Blends of the same fractions had quite different critical shear rates, depending on the procedure used to prepare them, even though their molecular weight distributions were identical. The change in viscosity with shear rate is not a unique function of molecular weight or melt viscosity. Fractions of linear polyethylene show a greater change in viscosity with shear rate than branched fractions of similar low shear melt viscosity. This suggests that the effect is related to chain entanglement or coordinated segmental motion.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1965.070090233
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  • 8
    Electronic Resource
    Electronic Resource
    Organotin polyesters (1965)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 3383-3388 
    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 interfacial polymerization technique was used in the preparation of organotion polyesters. Dialkyltin dihalides dissolved in an organic solvent immiscible with water were reacted with the dialkali metal or ammonium salt of a dicarboxylic acid. High yields of polyesters were obtained after short reaction times. The polyesters were generally insoluble and were high melting. Copolymers were also obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1965.070091015
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  • 9
    Electronic Resource
    Electronic Resource
    Certain fine structure and thermal properties of benzhydrylated cotton cellulose (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 817-828 
    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 present paper describes the results of a preliminary study of certain physical and thermal properties of benzhydrylated cotton yarns. The 200-yd. lengths of 7/2 yarn consisting of purified mercerized cellulose were reacted in a special reactor to various degrees of substitution from DS 0.31 to DS 1.22 with benzhydryl bromide in a mixture of equal volumes of 2,6-lutidine and dimethylformamide. The products were examined for tensile strength at break, which decreased only slightly with substitution; ultimate elongation, which was relatively uniform at 60-70% of the control yarn; and tenacity, which decreased with substitution largely due to added weight. The energy of rupture remained relatively constant at about 50% above the control. Tensile stiffness decreased progressively with substitution to about 25% of the control. Density decreased 10-11% with substitution. Crystallinity of the cellulose largely disappeared with substitutions above DS 1, and the lattice of benzhydryl cellulose began to appear. Stiffness, elastic recovery and work recovery were measured on 5-in. specimens of the yarn in an oven while they were subjected to repeated extension to about 1-2% and relaxed as the temperature was raised twice to 200°C. and lowered. During the heating phase of the first cycle the yarn underwent considerable heat adaptation. However, during the cooling phase and during both heating and cooling phases of the second cycle, the yarns showed generally favorable behavior. Attempts are made to interpret the results in terms of molecular modifications.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070110605
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of molecular weight distribution and branching on rheological parameters of polyethylene melts. Part I. Unfractionated polymersPresented at the 145th National Meeting of the American Chemical Society, New York, N. Y., September 1963. (1965)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 757-765 
    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: It is well known that the rheological behavior of polyethylene melts is affected by at least four variables: (1) molecular weight, (2) molecular weight distribution, (3) long-chain branching and its distribution, and (4) short-chain branching. Of these, the first three appear to have the largest effects. In the present paper an attempt is made to determine the effect of molecular weight distribution by rheological studies of polymers having similar molecular weight distribution by rheological studies of polymers having similar molecular weights and degrees of branching, but varying considerably in their molecular weight distributions as determined by fractionation. The rheological parameters studied were melt recovery, non-Newtonian behavior, critical shear rate, and melt strength. It is shown that the melt recovery increases uniformly as the molecular weight distribution broadens. The degree of non-Newtonian behavior, as measured by the exponent n of the power law, also increases with distribution breadth and is particularly affected by the amount of low molecular weight polymer present. Melt strength increases in a similar manner. Critical shear rate is inversely related to the breadth of the molecular weight distribution and is particularly dependent on the molecular weight of the highest fractions. The log of the critical shear rate is inversely proportional to the melt index recovery.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1965.070090232
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