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  • Polymer and Materials Science  (33)
  • Industrial Chemistry  (7)
  • GENERAL
  • 1955-1959  (41)
  • 1956  (41)
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  • 1955-1959  (41)
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  • 1
    Electronic Resource
    Electronic Resource
    The incorporation of aroyloxy radicals in polymer molecules (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 19 (1956), S. 87-92 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Initiation of the bulk polymerization of samples of 2-vinylpyridine with N-nitroso-N-phenyl-m-bromobenzamide and N-nitroso-p-bromoacetanilide gave polymers containing 0.06% and 0.52% bromine, respectively. Therefore, the aroyloxy radical is only about one-eight as reactive as the aryl radical for incorporation in a polymer molecule. This is a rough comparison, for there is no data upon which to base an estimate of the influence of the halogen substituent upon the reactivity of the parent free radicals. The purification of the polymers included an ether extraction of an acid solution of the substances to insure removal of all initiator fragments not attached to the polymer molecules. The presence of aroyloxy radicals in the polymers does not give assurance, however, that they were introduced in the step of chain initiation or even in the original polymerization process. For example, treatment of polystyrene with p-chlorobenzoyl peroxide was found to introduce 0.60% chlorine which through saponification proved to be a minimum of 96% chlorobenzoyloxy groups. Therefore, it seems highly probable that, when nitrosoamides are used as catalysts, aryl radicals may serve exclusively as chain initiators while a much smaller quantity of aroyloxy groups are incorporated by other mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.120199109
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  • 2
    Electronic Resource
    Electronic Resource
    Inhibition of polymerization. II. Methyl acrylate (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 19 (1956), S. 123-140 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of nine inhibitors on the 2,2′-azobisisobutyronitrile initiated polymerization of methyl acrylate in methyl propionate solution has been studied kinetically by a dilatometric method. The rate constants obtained are compared with those found for these same compounds in methyl methacrylate polymerization. The ratio of the reactivity of an inhibitor toward methyl acrylate and methyl methacrylate radicals is found to vary considerably from inhibitor to inhibitor; these variations in behavior seem readily interpretable in terms of polar and steric effects. Specifically, it is found that the three quinones - benzoquinone, 2,6-dichloroquinone, and 2,5-dichloroquinone - show a smaller increase in reactivity on going from methacrylate to acrylate than any of the other compounds studied. This is consistent with the presumably strongly “electron-accepting” nature of the quinone ring. On the other hand, the tetrachloroquinone, chloranil, shows a much larger increase in reactivity on going from methacrylate to acrylate. Models indicate that this different behavior is due to the existence of considerable steric hindrance in the reaction of the bulky methacrylate radical with chloranil and not to any difference among these quinones as regards their mechanisms of reaction with methacrylate and acrylate radicals. With the other compounds which showed inhibitory activity - trinitrotoluene, furfurylidene malononitrile, dinitrobenzene, and sulfur - the relative magnitude of the increase in reactivity varies in a manner consistent with the differing polarities of these four compounds.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.120199113
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  • 3
    Electronic Resource
    Electronic Resource
    A rapid method of constructing density gradient tubes (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 19 (1956), S. 598-598 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.120199331
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of degree of crosslinking in natural rubber vulcanizates. Part I (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 19 (1956), S. 225-236 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This paper examines the relationship between the stress-strain properties of highly swollen natural rubber vulcanizates and their equilibrium volume swelling. It is shown that the empirical relationship obtained can be described equally well by either the Flory-Huggins equation or the Flory modification of this equation, and values of the interaction constant μ for natural rubber in decane are determined. Observed differences in the values of μ obtained for sulfur and peroxide vulcanizates are interpreted in terms of the diluent effect of nonrubber constituents in the former. The effect of the initial molecular weight of the unmasticated rubber on these physical properties is examined and an empirical correction making allowance for chain segments terminated by a crosslink at only one end is obtained. The correction is larger than that derived by previous workers and possible sources of the observed differences are discussed. It is considered that internally self-consistent estimates of the degree of crosslinking of natural rubber vulcanizates may be obtained using the methods developed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.120199201
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  • 5
    Electronic Resource
    Electronic Resource
    The mechanism of chain initiation and chain transfer in the polymerization of vinylpyridineFrom the these submitted by Joseph A. Schufle and Irwin Cohen to the Graduate School of Western Reserve University in partial fulfillment of the requirements for the Degree of Doctor of Philosophy. Presented before the High Polymer Forum at the 116th meeting of the American Chemical Society at Atlantic City, New Jersey, September, 1949. (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 19 (1956), S. 285-296 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: (1) Polymerization of 2-vinylpyridine in p-chlorotoluene solution produced a polymer which, when oxidized with potassium permanganate in dilute sulfuric acid, gave no chlorophthalic acid, but a 35.7% yield of p-chlorobenzoic acid (based upon the halogen content of the polymer). Therefore, incorporation of the aromatic groups in the polymer, probably in the step of chain transfer, occurred by reaction with the side chain and not the nucleus of the p-chlorotoluene. The absence of chlorophthalic acid was significant, for a similar oxidation of α-(p-methylbenzyl)pyridine gave a 3% yield of terephthalic acid as well as a 23% yield of 2-(4-carboxybenzoyl)pyridine. (2) Permanganate oxidation of this same polymer in 25% sulfuric acid gave a 27% yield of p-chlorobenzoic acid. This represents the maximum yield of halobenzoic acid to be expected from a polyvinylpyridine containing trace quantities of halophenyl and pyridine nuclei separated by a chain of two or more carbon atoms. In contrast, similar oxidations in 25% sulfuric acid of α-(p-bromobenzyl)- and α-(p-chlorobenzyl)pyridine gave much smaller yields (16 and 14%, respectively) of the corresponding halobenzoic acids. In concentrated acid, the heterocyclic rings form stable salts and oxidation of the benzylpyridine type structure leads to preferential cleavage of the benzene nucleus. (3) Initiation of the polymerization of 2-vinylpyridine with N-nitroso-p-bromoacetanilide formed a polymer which, upon oxidation with potassium permanganate in 25% sulfuric acid, gave a 31% (average) yield of p-bromobenzoic acid. Since this yield is that expected from a polymer in which pyridine and bromobenzene rings are separated by a chain of two or more carbon atoms, beta carbon atoms addition in chain initiation by a bromophenyl radical is substantiated. (4) Polymerization of 2-vinylpyridine in bromobenzene solution provided a polymer which, upon oxidation with permanaganate in 25% sulfuric acid, gave only a 6% yield of bromobenzoic acid, corresponding to a bromobenzylpyridine structure in the polymer. Reasons are given why this data supports but does not prove the hypothesis that chain transfer consists of substitution in the bromobenzene nucleus by a polymer radical possessing a 2-pyridylmethyl structure.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.120199205
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  • 6
    Electronic Resource
    Electronic Resource
    Measurement of viscosity-average molecular weight of polymer solutions of unknown concentration (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 20 (1956), S. 431-435 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In a number of contexts it is of interest to determine the viscosity-average molecular weight of a polymer solution whose concentration is not known. Certain ways of ac-complishing this can be shown to reduce to the comparison of measurements of the specific viscosity of equiconcentrated polymer solutions in two different solvents. The limits of precision of this technique are indicated and checked experimentally on a number of solutions of known composition of mixtures of polystyrene fractions. The agreement between the found viscosity-average molecular weight and that calculated from the known composition of the polymer fraction mixture is satisfactory.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.120209602
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  • 7
    Electronic Resource
    Electronic Resource
    Viscoelastic behavior of polyisobutylene under constant rates of elongation (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 20 (1956), S. 89-100 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The use of stress-strain curves to characterize the linear viscoelastic properties of rubberlike materials is discussed. Tensile stress-strain curves for a high molecular polyisobutylene were measured at ten temperatures between -54 and 85°C. and at strain rates between 0.104 and 0.104 × 10-3 sec.-1. At a single temperature, the data superpose on a double logarithmic plot of stress divided by strain rate against strain divided by strain rate. By superposing data obtained at different temperatures, the temperature dependence of viscosity was obtained. All data for elongation up to 100% were combined to give a single reduced stress-strain curve, which extends over ten decades of reduced time. From the reduced curve, the stress-relaxation modulus was calculated and found to agree satisfactorily with published data.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.120209408
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  • 8
    Electronic Resource
    Electronic Resource
    Methylation of secondary cellulose acetate with diazomethaneThis work was supported in part by a research grant to the Textile Research Institute from the E. I. du Pont de Nemours & Co., Inc. (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 21 (1956), S. 273-277 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In an attempt to determine the acetyl group distribution in a commercial secondary cellulose acetate, it was desired to methylate fully the remaining free hydroxyl groups of the cellulose. In order to accomplish this, etherial diazomethane was used as the methylating agent. An anomalous effect was observed during the methylation reaction which was ascribed to a neighboring acetyl group participation. It consists of deacetylation accompanied by the introduction of methoxyl groups on the cellulose. The rate of reaction is controlled by the moisture content of the sample; however, a simple hydrolytic mechanism is not postulated since diazomethane is also required. Kinetic data are presented and two alternative mechanisms for the observed reaction are postulated.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.120219809
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  • 9
    Electronic Resource
    Electronic Resource
    Pyrolysis of polyacrylonitrile (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 22 (1956), S. 249-256 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyacrylonitrile of molecular weight 130,000 has been pyrolyzed under nitrogen, between 200° and 320°. The predominant gaseous products are hydrogen cyanide and ammonia; the rates of formation of these have been measured, and at 270° for example, after 300 minutes, only 10% of the available nitrogen is lost. A liquid distillate containing nitriles, amines, and unsaturated groups was also obtained. Using infrared absorption measurements, it was found that the nitrile groups of the polymer disappear as heating progresses, and C=N linkages appear. As heating is continued, evidence for aromatization is found. These experimental facts indicate ring formation to be an important reaction; the heat-stable residues are considered to be mainly fused pyridine systems.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.1202210107
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  • 10
    Electronic Resource
    Electronic Resource
    Sorption of water vapor by water-soluble polymers: Kinetic, equilibrium, and glass temperature dataPresented in part at the 128th Meeting of the American Chemical Society, Minneapolis, Minnesota, September, 1955. (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 22 (1956), S. 509-526 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Equilibrium and kinetic studies of the sorption and desorption of water vapor by poly(acrylic acid), poly(sodium acrylate), sodium carboxy methyl cellulose, methyl cellulose, and a series of poly(methyl acrylate) hydrolyzates in acid and sodium salt forms were made at 30°C. It was found, as expected, that equilibrium sorption increased and was greater for polymers containing strong-electrolyte type substituents than for those containing an equivalent number of weakly ionizable units. In general, the diffusion is somewhat slower than in the case of water-insoluble polymers. It was also found that water solubility of a polymer does not per se result in anomalous water sorption. In Methocel, for example, water diffusion is both Fickian and concentration-independent. All of the results, particularly those on the poly(methyl acrylate) hydrolyzates which ranged from completely water-soluble to insoluble systems, support the following conclusion: For water-soluble polymers both anomalous diffusion and relatively high glass temperatures are associated with high concentrations along polymer chains of very polar or ionic groups, such as —OH, —COOH, and CO2-Na+. Presumably both the anomalies and high transition temperatures are associated with restricted segmental mobility resulting from strong chain-chain interactions which originate in the highly polar and ionic, water-solubilizing chain substituents.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.1202210219
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