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  • Articles  (314)
  • Polymer and Materials Science  (314)
  • Cell & Developmental Biology
  • Physical Chemistry
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  • 1970-1974
  • 1955-1959  (314)
  • 1950-1954
  • 1935-1939
  • 1910-1914
  • 1955  (314)
  • Chemistry and Pharmacology  (314)
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  • Articles  (314)
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  • 1970-1974
  • 1955-1959  (314)
  • 1950-1954
  • 1935-1939
  • 1910-1914
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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 263-270 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When subjected to the effect of ionizing radiation, such as atomic pile radiation or gamma radiation, cellulose is rapidly degraded into a powdery material. A theoretical treatment shows that if the effect of radiation is to cause fracture at random in the main chain, the relation between intrinsic viscosity [η] and radiation dose R should be of the form: \documentclass{article}\pagestyle{empty}\begin{document}$$ \log [\eta] = - \alpha \log (R + R_0) + {\rm constant} $$\end{document} where R0 is a “virtual” radiation dose needed to produce the initial number-average molecular weight from a chain of infinite molecular weight. The published data of Saeman, Millett, and Lawton have been used to verify this formula, which leads to a relationship between [η] in cupriethylenediamine and viscosity-average molecular weight Mv: \documentclass{article}\pagestyle{empty}\begin{document}$$ [\eta] = KM_v^\alpha $$\end{document} with α = 0.71. The constant K has been evaluated by comparison with data given by Gralen, but is less accurately known. It is deduced that one million roentgen results in fracture of 0.16% of the monomer units in the main chain. The decomposition of carbohydrates under radiation, which occurs at the same time as main chain fracture, can be explained on the assumption that approximately one monomer unit is decomposed per main chain fracture. The study of intrinsic viscosity of irradiated polymers appears to offer an accurate means of evaluating α in the usual formula for intrinsic viscosity [η] = KMα.
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  • 2
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The cell model for r-mers and r-mer solutions developed by Prigogine, Trappeniers, and Mathot is applied to pure diphenyl, diphenylmethane, dibenzyl, and tolan (diphenylacetylene) and to their solutions in benzene. This model introduces new contributions for the excess functions arising from volume changes and modification of the curvature of intermolecular potential with change in composition. The excess functions are written in an explicit form and contain only molecular quantities without any arbitrary parameter. The agreement for the different excess functions (excess free energy, entropy, and excess volume) is satisfactory. The existence of a negative excess specific heat can also be understood on the basis of the cell model and is related to the negative excess volume.
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  • 3
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 193-202 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A chemical kinetic interpretation of the rheological behavior of high polymers has been proposed, in which the polar force of segments locks the adjacent segments in neighboring molecules in a similar way to crosslinking in vulcanized rubber. The change of such a crosslink caused by the thermal motion of segments and by external stress on the sample gives rise to rheological phenomena, such as the relaxation of stress or strain. The elasticity or viscosity of high polymers is related to the equilibrium crosslinkage which is affected not only by the temperature change but also by external stress. The structural viscosity, the yield point, or the effect of solvent on elasticity or on viscosity can also be understood according to this interpretation. The theoretical treatment gives many equations previously found in experiments: the equation for relaxation of deformation or stress, i.e., the four-element-model equation, the Dienes' equation with respect to the temperature dependence of elasticity of polyvinyl chloride, or Rabinovitch's equation for structural viscosity.
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  • 4
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 221-229 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Apparent first-order rate constants and activation energies for the alkaline hydrolysis of polyvinylpyrrolidone, polyactam, vinylpyrrolidone-maleic acid copolymer, N-isopropyl-γ-valerolactam, butyrolactam, and pyrrolidone-N-acetic acid were determined in order to study the influence of structure on the stability of the lactam ring. It was found that the behavior toward alkaline hydrolysis of polyvinylpyrrolidone closely resembles that of its low molecular analogue N-isopropyl-γ-valerolactam. It has been shown that a carboxyl function substituted near the lactam ring has a favorable influence on the ease of hydrolysis. Alkyl substitution on the lactam nitrogen, however, makes the lactam more resistant against hydrolysis.
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  • 5
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 271-276 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerization of acenaphthylene by boron trifluoride-ether complex as catalyst was carried out in benzene solution of various concentrations of the catalyst over a range of temperatures from 20 to 50°C. Over-all rate of the polymerization was found to be of the first order both for the initial concentration of the monomer and for that of the catalyst: \documentclass{article}\pagestyle{empty}\begin{document}$$ - d[M]/dl = k[M][C] $$\end{document} Activation energy required in the reaction was calculated to be 12.5 kcal./mole, and the molecular weight of polymers measured by the Gee osmometer was shown to be of the same order as found by previous workers.
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  • 6
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 305-319 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Absorption of solvent and swelling by nitrocellulose fibers and films, in binary solventhexane mixtures of varying concentration and involving ketones, acetates, and phthalates, have been compared. Equilibrium is less rapidly attained with films. With solvents of smaller molecular size the equilibrium absorption of fibers and films, at a given concentration, is the same, suggesting that all regions of the nitrocellulose are accessible to such solvents. With solvents of larger molecular size lower equilibrium absorption values are obtained with films, suggesting that only certain regions are accessible to these solvents and such accessibility is less in films. Where absorption values are similar, swelling of films and fibers are comparable and similar modes of solution are observed. The assumption that no hexane is absorbed appears to be justified at lower solvent concentrations, but at higher concentrations the mixture in equilibrium with the nitrocellulose may be imbibed. Assuming such imbibition, the relationship between swelling or solvent power and cohesive energy density of solvent is interpreted in terms of interaction between solvated polymer and mixture.
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  • 7
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A detailed study has been made of the intrinsic viscosity-molecular weight relationship for a polybutadiene prepared at 50°C. and one prepared at 5°C. Original fractions were at least twice refractionated from very dilute solutions in an attempt to obtain fairly sharp distributions. Fox-Flory K constants are observed to decrease with increasing molecular weight in each case, and the intrinsic viscosity-molecular weight plots show a curvature. This is interpreted to be a result of branching. A method of plotting the data is proposed which simultaneously yields the K for unbranched material and an estimate of the degree of branching. It is estimated that, in polybutadiene prepared at 50°C., one out of 6500 monomer units is involved in a branch, and that in 5°C. polybutadiene, one out of 10,000.
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  • 8
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A study of the copolymerization of 1,1-dihydroperfluorobutyl acrylate with methyl methacrylate, styrene, and butadiene has shown that this monomer is similar to acrylonitrile (e = 1.2, Q = 0.44) in its copolymerization behavior and considerably different from methyl acrylate (e = 0.6, Q = 0.42). This illustrates the strongly electronegative character of the C3F7 group. The higher Q value (0.75) may be considered evidence of higher resonance stability of the radical adduct due to the perfluoroalkyl substituent.
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  • 9
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 592-594 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 10
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 575-590 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Viscosities of potassium cellulose sulfate solution were measured in the presence of KCl, HCl, BaCl2, and cetyl trimethyl ammonium bromide. The reduced viscosity of an aqueous solution of potassium cellulose sulfate was shown to follow the general formula proposed by Fuoss and Strauss for the polyelectrolyte solutions: \documentclass{article}\pagestyle{empty}\begin{document}$ {{\eta _{{\rm sp}} } \mathord{\left/ {\vphantom {{\eta _{{\rm sp}} } c}} \right. \kern-\nulldelimiterspace} c} = \left[ {{A \mathord{\left/ {\vphantom {A {\left( {1 + B\sqrt c } \right) + D}}} \right. \kern-\nulldelimiterspace} {\left( {1 + B\sqrt c } \right) + D}}} \right] $\end{document} where A, B, and D are constants determined by experiments and c is concentration of the polyelectrolyte. In this article, a derivation of an empirical viscosity equation for the mixture of potassium cellulose sulfate and added electrolyte was shown. The empirical equation thus obtained for the mixture appears to express the viscosity behavior in the presence of low concentration of added electrolyte. The equation consists of two factors and has the following general form: \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{\eta _{{\rm sp}} }}{c} = \left( {\frac{A}{{1 + B\sqrt c }} + D} \right)\left( {1 - \frac{1}{{a + b\left( {{{c^\psi } \mathord{\left/ {\vphantom {{c^\psi } {m^\phi }}} \right. \kern-\nulldelimiterspace} {m^\phi }}} \right)}}} \right) $\end{document} where A, B, D, a, b, ψ, and φ are all experimental constants. The first factor concerns the viscosity behavior of the aqueous solution of the polyelectrolyte in the absence of added electrolyte, and the second factor is the correction caused by the addition of electrolyte. The first factor increases while the second decreases upon dilution. As the results of the competitive tendencies, the existence of the maximum reduced viscosity at certain concentration of the polyelectrolyte can be explained. The physical picture corresponding to the first and the second factors respectively is not absolutely clear, but it is suggested that there exist two opposing tendencies that affect the viscometric behavior of a polyelectrolyte solution. One of these, that tends to increase the viscosity, is the increase in molecular dimensions upon dilution or upon decreasing the ionic strength. The second, that causes a decrease in viscosity, is attributable to the decrease in intermolecular interaction with dilution.
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  • 11
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 16 (1955), S. 89-91 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 12
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 16 (1955), S. 99-100 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 13
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 16 (1955), S. 155-162 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 14
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 16 (1955), S. 163-175 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A short review is given of the development of the theory and of the new experimental technique of x-ray low-angle scattering. The study of human γ-globulin leads to a cylindrical particle of about elliptical cross section with axes of 19 and 57 A. and with a length of 230-240 A. The volume is found to be 1.98 × 105 A.3, which involves a molecular weight of 1.62 × 105 in satisfactory agreement with the value found by ultracentrifuge measurements.
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  • 15
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 16 (1955), S. 209-219 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 16
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 503-514 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The various proposed structures for polymers derived from benzyl type compounds have been discussed and the likelihood of these structures considered in the light of a study of their preparation and properties. Both the para substituted structure of Shriner and Berger and the pendant structure of Henne and Leicester were rejected chiefly on the basis of physical properties, degradation behavior, and x-ray and infrared evidence. Flory's randomly branched structure also fails to account for the degradation behavior and the infrared spectrum. A new configuration which is a nonrandomly substituted, highly branched molecule is advanced. This structure contains predominantly two types of benzene rings, i.e., a relatively small number of highly substituted rings and a considerably larger number of monosubstituted benzenes existing in the form of pendant benzyl groups.
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  • 17
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A number of polymers of acrylates of fluorine-containing ether alcohols were prepared and studied. The side-chain structures investigated are: CF3CH2OCH2CH2OCO, CF2HCF2OCH2CH2OCO, CF2HCF2(OCH2CH2)2OCO—, CF3CF2CF2CH2OCH2CH2OCO, and RfOCF2CF2CH2OCO—, where Rf equals CF3, CF3CF2, CF3CF2CF2, and CF3CF2CF2CF2—. Of these, the last group has glass transition and stiffening temperatures 20-25°C. lower than those of most of the others, together with the small swelling in solvents characteristic of the RfCH2OCO— series. It is concluded that polymer behavior, particularly the modulus-temperature and solubility characteristics, may be very profoundly affected by the nature of the side chains. An interpretation of the behavior of the polyacrylates of the fluorinated ether-alcohols in terms of increased side-chain flexibility due to ether “swivel joints” is attractive, but may not be justified.
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  • 18
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 16 (1955), S. 193-199 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new method has been developed for obtaining molecular weight distribution curves from turbidimetric titration data. The latter are plotted directly in a curvilinear coordinate system where one set of axes is the solubility frequency curves for the polymer in question and which can be constructed once and for all. The method is very simple and no assumptions about the homogeneity of successive fractions are made. A formal mathematical treatment of the procedure is also given.
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  • 19
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The viscosity slope constant k′, i.e., \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\lim }\limits_{c \to 0} \frac{{d\left( {{{\eta _{sp} } \mathord{\left/ {\vphantom {{\eta _{sp} } c}} \right. \kern-\nulldelimiterspace} c}} \right)}}{{dc}}\frac{1}{{[\eta ]^2 }} $\end{document}, is shown to be of increasing significance in polymer science as a molecular-weight-independent criterion of solvent power and as a parameter sensitive to various changes in polymer structure, such as long-chain branching. Ideally, it is a dimensionless parameter, independent of molecular size, which arises only from the mutual hydrodynamic interaction of polymer molecules and depends, therefore, on the intrinsic flexibility of the polymer chain and on the polymer density in the coiled molecule. In real systems, however, other interactions may contribute, sometimes very significantly, to k′. For such real systems, the general expression: \documentclass{article}\pagestyle{empty}\begin{document}$ k' = k + a + \frac{K}{{[\eta ]^2 }}\left( {[\eta ]_{(2)} - [\eta ]_{(1)} } \right) $\end{document} is suggested. In ternary systems, polymer-polymer-solvent, ideal expressions for ηsp/c and k′ are developed, that for k′ being: \documentclass{article}\pagestyle{empty}\begin{document}$ k' = \sum\limits_i {\sum\limits_j {\surd \bar k_i [\eta ]_i w_i {{\surd \bar k_j [\eta ]_i w_i } \mathord{\left/ {\vphantom {{\surd \bar k_j [\eta ]_i w_i } {(\sum\limits_i {[\eta ]_i w_i } )^2 }}} \right. \kern-\nulldelimiterspace} {(\sum\limits_i {[\eta ]_i w_i } )^2 }}} } $\end{document} It is proposed that deviations from ideal behavior so defined are due to nonhydrodynamic polymer-polymer interactions and might be used to detect and measure the strength of such interactions. Some preliminary data for the system polystyrene-poly(methyl methacrylate)-m-xylene are presented and discussed.
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  • 20
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 16 (1955), S. 201-208 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The addition of carboxylic acid to Epon 834-phthalic anhydride resins accelerates the rate of cure. The maximum thermal yield point corresponds to reaction of all the epoxide groups in the ratio of two anhydride carbonyls to one epoxide oxygen or of one acid carbonyl to one epoxide oxygen. The initial presence of some secondary alcohol groups appears to be essential for initiation of reaction as suggested by Fisch and Hofmann. Carboxylic acids react directly with epoxide groups to produce secondary alcohols which in turn react with phthalic anhydride, regenerating carboxylic acid groups. Succinic acid gives a rapid cure (although not as fast as amines) to a resin with only slightly lowered thermal yield point, while benzoic acid depresses the yield point by about 15° because it acts as a chain-stopper.
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  • 21
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 16 (1955), S. 235-244 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A number of examples are presented to show that cationic dyes bind to polymeric acids by simple electrostatic forces. Competitive binding for the substrate is illustrated by the addition of hydrogen ions, calcium ions, and streptomycin. Anionic binding to uncharged or to negatively charged substrates is attributed to hydrogen bonding with the carbonyl groups of the substrate. Van der Waals' forces also play an important role in the binding. Illustrations are given for the substrates, native serum albumin, denatured ovalbumin, polyvinylpyrrolidone, and water-soluble urea-formaldehyde resin. In the last-named case the binding increases with increasing molecular weight of the substrate. A new fluorometric technique for following the binding of anions is described. The changes in spectral and photochemical properties which dyes undergo when bound are summarized.
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  • 22
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    Journal of Polymer Science 16 (1955), S. 273-281 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The rates of acid-base catalyzed reactions of small molecules in polyelectrolyte solutions should, in general, differ from rates in simple electrolytes at the same pH. The effect is due to the small ionic activity coefficients and the counterion distribution in polyelectrolyte solution and will be accentuated if there is an energetic interaction between the polyion and the reacting molecules. In predicting the reactivity of groups attached to polyions, both electrostatic factors and specific chemical effects have to be considered. The reactivity of p-nitrophenyl ester groups in neutral solution was observed to be increased by a factor of a million when groups were attached to a polymeric acid and the effect was interpreted by a change in the reaction mechanism. The rate of the basic hydrolysis of p-nitroanilide groups attached to polymeric acids was very low and depended strongly on the substitution of both the α and the γ carbon. The pronounced acceleration of the hydrolysis by small concentrations of barium ions was interpreted as a chelation effect. The possible use of polyelectrolytes with reactive side chains as models of enzyme-substrate complexes is discussed.
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  • 23
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    Journal of Polymer Science 17 (1955), S. 1-20 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: As an extension of our original program, one more polystyrene fraction was investigated in numerous laboratories by means of viscosimetry, osmometry, light scattering, and ultracentrifuge. The various results are compared and critically discussed. Possible explanations and suggestions for improvement are offered in those cases in which considerable discrepancies occur. The viscosity results show satisfactory agreement. The discrepancies among osmotic results are believed to be due largely to unsatisfactory performance of the so-called semipermeable membranes. Discrepancies among light-scattering results can mostly be traced back to the unsatisfactory state of the various calibration techniques. The results obtained with the ultracentrifuge agree quite satisfactorily.
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  • 24
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The chain transfer constant of polymethyl methacrylate in the polymerization of methyl methacrylate and styrene is determined by adding polymer of low chain length to the polymerizing system. This has no influence on the rate of polymerization, but the degree of polymerization of the growing polymer is lowered. This effect is ruled by the same equations as the effect of regulators. The chain transfer constant of polymethyl methacrylate is composed of two parts, corresponding to the middle groups and to one end group arising a t the disproportionation. Polystyrene has no end group effect, because the chain termination is made by combination. It is possible to estimate the degree of branching with the chain transfer constants determined by this way.
    Notes: Die Übertragungskonstante von Polymethylmethacrylat hei der Polymerisation von Methylmethacrylat hzw. Styrol wird dadurch bestimmt, dass man Polymeres von sehr kleiner Kettenlänge dem polymerisierenden Stoff zusetzt. Das zugesetzte α-Polymere beeinflusst nicht die Bruttogeschwindigkeit, setzt aber den Polymerisationsgrad des entstehenden Polymeren herab. Für diesen Vorgang gelten dieselben Gleichungen wie für niedermolekulare Regler. Die Übertragungskonstante von Polymethacrylat setzt sich aus zwei Anteilen zusammen, welche den Mittelgruppen und einer Endgruppe entsprechen. Die wirksame Endgruppe ist hei der Disproportionierung entstanden. Polystyrol zeigt keinen Endgruppeneffekt, da das Kettenwachstum durch Kombination beendet wird. Aus den gemessenen Übertragungskonstanten kann der Grad der Verzweigung bei Polymethacrylaten und Polystyrolen abgeschätzt werden.
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  • 25
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    Journal of Polymer Science 17 (1955), S. 79-80 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 26
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    Journal of Polymer Science 17 (1955), S. 81-88 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Intrinsic viscosity measurements of polyacrylonitrile fractions in dimethyl formamide at 25°C. and molecular weight determinations by the sedimentation-diffusion method led to the following relation : The data are consistent with the model of a coiled chain, impenetrable to the solvent, in agreement with the theories of Flory and co-workers. The influence of the concentration upon the sedimentation constant was interpreted by an extension of the concept of the equivalent hydrodynamic sphere to the range of small finite concentrations. The following relation was thus obtained: K should be a universal constant and its value is about 1.6 for most flexible polymers.
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  • 27
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    Journal of Polymer Science 17 (1955), S. 116-116 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 28
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    Journal of Polymer Science 17 (1955), S. 117-124 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A viscosity-weight average molecular weight relationship was obtained for fractionated polyvinyl acetate in a thermodynamically “good” solvent acetone at 30°C. This relationship is represented by [η] = 8.6 × 10-5Mw0.74. The value of the root-meansquare end-to-end distance is approximately three times as large as the theoretical value for a chain with completely free rotation. The values of the osmotic second virial coefficient indicate the polymer molecules are expanded beyond their random flight dimensions. Consideration of the thermodynamic interactions in “good” solvent results in approximately constant values for A2M/[η] and A2M2/(r2)3/2. The average value obtained for the Flory universal constant is 1.98 × 1021.
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    Journal of Polymer Science 17 (1955), S. 137-140 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
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    Journal of Polymer Science 16 (1955), S. 459-469 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A previous analysis of the polymerization of liquid sulfur has been revised to take account of specific heat data now available and some new experimental evidence presented here. It is confirmed that liquid sulfur is essentially an equilibrium mixture of S8 rings and long free radical chains. The heat of polymerization (S8 → inifinite chain) is estimated as 3180 cal./mole of S8 at 432°K., where polymerization sets in rather abruptly; the corresponding entropy of polymerization is +7.4 cal. mole-1 deg.-1. There is evidence for the presence of rings of more than 8 atoms; the concentration of these reaches a maximum of ca. 1% in the neighborhood of the critical polymerization temperature (432°K.). Magnetic susceptibility measurements place an upper limit of 2 × 10-2 moles l.-1 on the free radical concentration. From this and other lines of evidence it is concluded that the heat of scission of sulfur chains does not exceed 35 kcal., and an explanation is put forward.
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    Notes: The chain transfer constants of normal and tertiary mercaptans with polystyrene radicals at 50°C. are, respectively, 19 and 4.5, with polybutadiene radicals, respectively, 19 and 3.7. The values are somewhat larger at 5°C., corresponding to an activation energy for transfer about 1 kcal./mole smaller than for propagation. At equilibrium 0.58 g. of n-octyl, 0.62g. of tert-octyl, 0.25 g. of n-tetradecyl, and 0.26 g. of tert-hexadecyl mercaptan can be dissolved per gram of polystyrene in emulsion, but the rate of attainment of equilibrium is extremely slow with the higher molecular mercaptans. The small apparent transfer constants of the higher mercaptans in emulsion polymerization are due to the slow rate of transport to the polymer particles. This transport is greatly accelerated by the addition of alcohol, which makes the distribution toward the water layer more favorable. In general the solubility in water of the mercaptan (or modifier in general) is the most important factor, the diffusion coefficient being of only secondary significance in a comparison of compounds of approximately the same molecular weight.
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    Notes: The validity of the Flory-Schulz distribution of chain length in equilibrium polymers produced from ∊-caprolactam and water (Nylon 6) over a DP range from ∼14 to ∼90 is tested by determination of the content of monomer (∊-aminocaproic acid, ACA) by means of a chromatographic technique. Experiments show general agreement with a simple theoretical relationship (P̄n1 = N, where P̄ = number average DP of chains, n1 = number of ACA molecules, and N = total number of chains), required for equilibrium if equal reactivity of all functional groups independent of chain length is assumed. Moderate deveiations from this relation, which seem to occur at higher DP values (P̄ ∼ 90) require further investigation.
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    Journal of Polymer Science 16 (1955), S. 505-515 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The turbidimetric titration method, used previously to determine molecular weight distributions in polymers, has been used for the qualitative examination of various polymers: mixtures containing block copolymer (styrene-methyl methacrylate or vinyl acetate-methyl methacrylate), polystyrenes prepared in branching studies, and commercially prepared polystyrenes. The method is a sensitive and rapid one and is suitable for the examination of very small quantities of polymer. A semiautomatic titration apparatus is also described.
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    Journal of Polymer Science 17 (1955), S. 309-310 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Polymer Science 17 (1955), S. 365-374 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The activity of silver ion was measured potentiometrically with various sample solutions of silver or silver-sodium salt, prepared from three different kinds of carboxymethylcellulose, for the purpose of elucidating these several points: dependence of the activity coefficient of counter ion upon the concentration of polyelectrolyte in salt-free solutions; influence of the silver content of the sample upon activity coefficient; salt effect on activity coefficient; and dependence of activity coefficient upon the degree of neutralization. These experimental results indicate that the characteristics of polyelectrolyte solutions are in many respects quite different from those of simple electrolyte solutions. The applicability of the theory proposed by Ōsawa, Imai, and Kagawa is discussed in some detail, although the discussion is restricted to the salt-free system only.
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    Journal of Polymer Science 17 (1955), S. 379-390 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Exposure to high energy radiation offers a means of producing controlled branching in long chain polymers. Branched silicone polymer molecules were obtained by exposing linear molecules to high energy radiation. The increase in weight-average molecular weight calculated theoretically from the radiation dose was compared with the value deduced from measurements of intrinsic and bulk viscosity, ignoring the effect of branching. The ratio of these measurements show the apparent reduction in molecular weight (as measured by viscosity methods) when branched molecules are present. In particular it is found that the reciprocal bulk viscosity decreases uniformly with degree of branching (or crosslinking) until the gel point, when the weight-average and bulk viscosity become infinite.
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    Journal of Polymer Science 17 (1955), S. 417-421 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
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    Journal of Polymer Science 17 (1955), S. 425-428 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
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    Journal of Polymer Science 17 (1955), S. 99-106 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The relation between molecular size and weight for polystyrene in cyclohexane at 34, 43, and 57°C. and toluene at 20°C. has been determined by a light scattering method. For the molecular weight range, half-million to five million, the data suggest a linear relationship:L2 = κ (M - b) where κ and b are parameters which have their higher values in better solvents.
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    Journal of Polymer Science 17 (1955), S. 133-135 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Polymer Science 17 (1955), S. 145-147 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Polymer Science 17 (1955), S. 142-145 
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    Journal of Polymer Science 17 (1955), S. 151-153 
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    Journal of Polymer Science 17 (1955), S. 159-177 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystal structure of nylon 6 (—NH (CH2)5CO—)p has been determined by interpretation of the x-ray diffraction patterns given by drawn, rolled fibers. The determination was part of a program to investigate the relation between structure and physical properties, in particular melting point. Nylon 6 melts 50°C. lower than its isomer nylon 66 (—NH (CH2)6NH·CO (CH2)4CO—)p; it had been suggested that this was due to deficient hydrogen-bond formation in nylon 6 crystallites. The unit cell contains eight chemical units (—NH (CH2)5CO—) and is monoclinic with a = 9.56 A., b = 17.24 A., c = 8.01 A., and β = 671/2°. Calculated density = 1.23. Observed density for a drawn monofilament = 1.16. The structure consists of planar chains of CH2 groups and amide groups tilted 7° from the (001) plane. Alternate chains in this plane are oppositely directed, an arrangement which allows all hydrogen bonds to be made perfectly. The hydrogen-bonded sheets of atoms are packed in an “up-and-down” staggered configuration along the c-axis. Distances between atoms in neighboring molecules are all normal van der Waals contact distances. It appears, from a general survey of polyamide melting points published elsewhere, that the determining factor is the number of CH2 groups between the amide “anchor points” - polymers with odd numbers of CH2 groups melt lower than those with even numbers. The present work shows that the odd number of CH2 groups in this polymer does not lead to deficient hydrogenbond formation, and that the lower melting point of nylon 6 as compared with nylon 66 must be ascribed to some other cause, possibly connected with the propagation of vibrations along odd-numbered chain segments.
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    Journal of Polymer Science 17 (1955), S. 207-214 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
    Notes: An accurate semimicro capillary viscometer is described in which dilutions can be made. A glass valve assembly eliminates evaporation and makes operation convenient. Techniques for semimicro work are described and specifications are given for an instrument suitable for intrinsic viscosity determinations with 1 milliliter of solution.
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    Notes: Modifiers with bis-type structures are of interest as a means for conferring reactive groups onto the highest possible fraction of polymer chain ends. Various disulfides and other bis-type compounds - some with reactive groups attached - were compared as to their effectiveness as modifiers in low conversion bulk styrene polymerizations and studies made of their mechanism of cleavage. Alkyl disulfides of primary thiols had transfer constants too low to be of much interest for this work, even when substituted at carbons near the sulfur-sulfur bond. Aryl disulfides proved to have much higher transfer constants, and substitution on each ring with appropriate groups offered a means both of increasing the transfer constant and of incorporating desired groups.It has been shown quite conclusively that aryl disulfides cleave so as to confer one-half the molecules onto each end of the polymer. This was demonstrated by analyzing the end group concentrations of styrene polymers of wide molecular weight range which contained various types of end groups - carboxyl, amino, naphthyl, and benzothiazyl - and comparing, wherever possible, with polymers modified with thiols containing similar groups.Polymerizations carried out at 25, 50, and 75°C. with certain of the bis-type compounds and with a normal and a tertiary mercaptan showed that activation energies are very slight if the transfer constant is high, and begin to reach significant levels only at low levels of transfer constant.
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    Journal of Polymer Science 17 (1955), S. 274-274 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Polymer Science 17 (1955), S. 311-314 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
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    Journal of Polymer Science 17 (1955), S. 317-318 
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    Journal of Polymer Science 17 (1955), S. 351-364 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
    Notes: The orientation of the crystallites in spherulites was investigated by using special microbeam x-ray techniques. The materials studied were: polyhexamethylene adipamide and sebacamide, polyethylene, and polyethylene terephthalate. In all these substances the c axes (molecular chains) were perpendicular to the radii of the spherulites, with some deviation from strict perpendicularity in the case of polyethylene terephthalate. The particular orientation of the crystallites around their c axes was in full agreement with the observed sign of birefringence, in the positive and negative polyamide spherulites, in polyethylene (where the indirect deduction made in earlier works has also been confirmed), and in the negative spherulites of polyethylene terephthalate. In the positive polyethylene terephthalate spherulites, while a fit between x-ray results and birefringence might still be possible, it is somewhat doubtful whether the sign of birefringence could be accounted for by the crystallite orientation alone. The possible arrangements of the crystallites is discussed and it is suggested that the picture of closely coiled helices with the molecules lying along the winding direction might offer the most satisfactory explanation.
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    Journal of Polymer Science 17 (1955), S. 375-378 
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    Topics: Chemistry and Pharmacology , Physics
    Notes: An attempt is made at giving a quantitative explanation for the variation of the apparent cross-termination coefficient in copolymerization as a function of the composition of the reaction mixture. The formula developed is applied to the system butyl acrylate-styrene.
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    Journal of Polymer Science 17 (1955), S. 410-410 
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    Journal of Polymer Science 17 (1955), S. 411-415 
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    Notes: The structure of certain novolacs, prepared by polycondensation of formaldehyde with phenol, p-cresol, and m-cresol respectively, was investigated. The novolacs were transformed into saturated hydrocarbons, thus expelling the oxygen, by a relatively mild high pressure hydrogenation (300°C., 250 atm.) using 100% by weight of a nickelcopper on kieselguhr catalyst. It can be expected that this treatment does not alter the structural frame of the molecules. From ultimate analysis and physical constants of the hydrocarbons, conclusions were made as to the structure of the novolacs. They are linear thermoplasts; no “extra” rings are present.
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    Journal of Polymer Science 17 (1955), S. 428-431 
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    Journal of Polymer Science 17 (1955), S. 438-440 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Polymer Science 17 (1955), S. 445-446 
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    Journal of Polymer Science 17 (1955), S. 447-472 
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    Topics: Chemistry and Pharmacology , Physics
    Notes: The spherulites are built of distinct fibrillar units and their fine-structure presents two problems: the arrangement of these units and their internal structure. In the present paper the first has been treated in greater detail. Based on direct observations, and on earlier works on nonpolymeric spherulites, a regular periodic branching mechanism of the fibrillar units is proposed, where, in the case of maximum regularity, the position of each branch with respect to the preceding one is defined by one constant branching period and one constant angle in the two-dimensional case, and by one constant branching period, two constant angles, and a constant direction of rotation in the three-dimensional case. The various stages of such a spherulitic growth were directly observed in suitable samples. It is shown that this mechanism can lead to helices, to be referred to as “large-scale helices,” which produce the previously observed zigzag extinction effects. The effects of the thickness of the crystallizing layer is followed, and possible connections between these effects and more general problems of crystal growth are indicated. Investigations of the fine-structure of the fibrils indicate a closely coiled rope-like arrangement in samples suitable for these observations. These are on a size of 400 A. and upward, sometimes reaching the limit of the optical microscopic resolution dependent on the preparation. They will be referred to as “small-scale helices.” These units appear to be built of and connected by much smaller fibrils which themselves possess a periodicity of 100-200 A. or less. The possible reasons for coiling and its relation to the perpendicular orientation found in Part II are discussed, and it is suggested that branching could be a possible consequence of the coiling structures. The conclusion is reached that, as far as the morphology is concerned, crystallization in polymers represents a special case of the formation of crystalline aggregates in viscous media.
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    Journal of Polymer Science 17 (1955), S. 547-551 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
    Notes: Decay of stress to zero stress followed by spontaneous elongation occurs in samples of stretched unvulcanized natural rubber in the temperature region of crystallization. Experimental results showing the effect of temperature and elongation on the rate of stress decay are presented.
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    Journal of Polymer Science 17 (1955), S. 583-586 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
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    Notes: Apparent specific volumes of two, previously well-characterized, polystyrene fractions were determined at 25° in solvents offering an interesting display of polymer/solvent interactions. Adaptations of differential pycnometry techniques permitted a sensitive detection of the small density differences between solvents and solutions, allowing four significant figures in the apparent specific volumes at concentrations as low as 0.20%. The measurements unambiguously confirm the solvent and concentration dependencies. The solvent dependency at high dilutions also confirms the anomaly that the extremes in polymer/solvent interactions causing very good and very poor polymer solubility yield higher values for the partial specific volumes of polystyrene than obtained for the intermediate range of interactions. The concentration dependency permits indirect approximations of the functions, ΔH̄1 and ΔH̄2 vs. poIymer concentration. The deviations from athermal mixing are greater and more irregular than anticipated, and are shown frequently to complicate both experimental and theoretical studies of the properties of dilute solutions. The thermodynamic behavior of dilute solutions of polystyrene in butanone appears to be particularly complex.
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    Notes: The results of a large number of streaming birefringence studies on dextran fractions, both native and degraded, produced by Leuconostoc mesenteroides are reported. The following solvents have been examined, all in admixture with varying proportions of glycerol (to enhance the solvent viscosity): water (with and without prior autoclaving), aqueous sodium hydroxide, formamide, and ethylenediamine. The results are surprisingly independent of the solvent used. Ethylenediamine-glycerol (equal parts by weight) was adopted for further investigation because of the high solvent viscosity. This solvent was found to yield a small birefringence with extinction angle near zero degrees, which, however, contributed no appreciable error except at polymer concentrations below 0.3%. Results were found to be substantially independent of polymer concentration and of temperature. Characteristically, the dependence of extinction angle on gradient was found to be much less than is to be expected for solutions of homogeneous, rigid molecules. It is concluded that this cannot be due to heterogeneity, at least in the case of certain well-fractionated preparation, and must be attributed to flexibility of the polymer molecule. It is shown that extrapolation of the apparent rotary diffusion constants to zero gradient can be carried out in most cases with some confidence. The resulting values, which should characterize the rotary diffusion properties of the undistorted polymers, are shown to be quite reasonable in terms of the known intrinsic viscosity and molecular weight of the fractions. The reduced birefringence of the various fractions is shown to be rather rigorously proportional to their intrinsic viscosity. Further, the extinction angles are found to approach a lower limit, at high gradient, which is related also to the intrinsic viscosity through the empirical equation Xlim = 24/[η]1/4.
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    Journal of Polymer Science 18 (1955), S. 47-54 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: From complete equatorial x-ray diffusion diagrams of dry and wet ramie we attempted to determined the real structure of the fibers, but not to difine an ideal structural model. Because cellulose contains several kinds of atoms, the electronic density repartition function and not the atoms center repartition function was considered. This function can be obtained directly from the photometric data of the equatorial diagrams G. Fournet has developed a method by which that function can be obtained from the model of Meyer and Misch. The synthetic curve has been compared with two experimental curves, and shows better agreement in the case of wet ramie. It was assumed that, perpendicular to the fiber axis, dry cellulose is relatively homogeneous from the point of view of electronic density but strongly perturbed at small distances (local distortion of the periodic unit); wet ramie, more heterogeneous due to the swollen molecular regions, presents highly crystalline regions of about 100 Å.
    Notes: A partir du diagramme équatorial complet de diffusion des rayons X par la ramie sèche et mouillée, nous avons cherché non pas à préciser un modèle idéal de structure cristalline mais plutôt à obtenir des renseignements sur la structure réelle des fibres. Comme la cellulose contient plusieurs sortes d'atomes, nous avons considéré la fonction de répartition des densités électroniques et non celle des centres d'atomes. Cette fonction peut s'obtenir directement à partir des données de photométrie des diagrammes équatoriaux. Par ailleurs, G. Fournet a développé une méthode permettant d'obtenir cette fonction à partir du modèle de Meyer et Misch. Nous exposons la comparaison de la courbe synthétique avec les deux courbes expérimentales et montrons que l'accord est meilleur dans le cas de la ramie mouillée. Nous pensonsque dans le plan perpendiculaire à l'axe de fibre la cellulose sèche est assez homogène en densité électronique mais très perturbée à petite distance (distorsions locales de la maille) tandis que la ramie mouillée, plus hétérogène à cause des zones gonflées présente des zones cristallines presque parfaites de l'ordre de 100 Å.
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    Journal of Polymer Science 18 (1955), S. 583-585 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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    Journal of Polymer Science 18 (1955), S. 595-595 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
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    Journal of Polymer Science 18 (1955), S. 597-598 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Polymer Science 18 (1955), S. 153-156 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Polymer Science 18 (1955), S. 189-200 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method of investigating the tear behavior of rubber vulcanizates is described. The method, based on the tear criterion of Rivlin and Thomas, involves the determination of the energy required to propagate a tear and its dependence on the rate of propagation. The type of test-piece employed and the methods of measuring the energy and rate of tear propagation are described and discussed. Two principal types of tearing, indicative of different tear processes, are described. Experimental results for natural rubber and GR-S gum vulcanizates, obtained over a wide range of temperature and rate of propagation, are given to illustrate the method. The results indicate that the nature of the tear process and the resistance to tearing, as represented by the energy required to propagate a tear, can change appreciably with the rate of propagation and the temperature. The significance of these changes is discussed.
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    Journal of Polymer Science 18 (1955), S. 257-274 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The viscosities of preparations of sodium polymethacrylate and polyvinyl-n-butylpyridinium bromide have been measured in water and salt solutions in the Couette viscometer down to very low concentrations and rates of shear. The dependence of reduced specific viscosity upon polymer concentration has been compared with that for DNA in water and salt solutions. It is concluded that there is a finite effect of salts upon the intrinsic viscosity of the synthetic polyelectrolytes in contrast to the result found with DNA. The viscosity behavior of solutions of intermediate concentration is very similar to the of DNA solutions. The shape of the reduced viscosity-concentration plots has been interpreted as arising from the combined effect of interaction and contraction of the molecules with increasing concentration.
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    Journal of Polymer Science 18 (1955), S. 305-306 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
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  • 70
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
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    Notes: The dynamic moduli and loss factors have been determined for high molecular samples of GR-S and natural rubber. Comparison of the two sets of data shows that the general characteristics of the two materials are quite similar. The main differences are that GR-S shows a higher temperature for the apparent second order transition, and also a higher value for the modulus in the relatively level portion of the highly elastic region. The usual superposition procedures are used for correlating the data. Several indications that the equivalence of frequency and temperature may not be of universal applicability are noted. It is suggested that the higher elastic plateau modulus of GR-S my, in conjunction with usual levels of vulcanization, lead to a modulus dispersiion with its attendant loss and thus be a contributing factor to the lower resilience and higher heat development characteristic of GR-S.
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    Journal of Polymer Science 18 (1955), S. 303-304 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
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    Journal of Polymer Science 18 (1955), S. 307-310 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Polymer Science 18 (1955), S. 314-314 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Polymer Science 18 (1955), S. 321-334 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
    Notes: Experiments are described in which the temperature dependence of crystallization in natural rubber, unvulcanized and vulcanized by a peroxide, was investigated dilatometrically over the temperature range -37 to 0°C. Avrami type time functions describe the progress of crystallization to a first approximation. The numerical parameters indicate the growth of spherical crystal structures from nuclei which appear randomly at a constant rate in a purified rubber. It is shown that classical nucleation theory describes the temperature dependence to a first approximation. The retardation of crystallization caused by the introduction of crosslinks is ascribed partly to a reduction in chain segment mobility and partly to the prohibition of crystal nucleus formation around each crosslink. Crystal nucleation appears to be promoted in plantation smoked sheet rubber by the nonrubber constituents at temperatures below 0°C.
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    Journal of Polymer Science 18 (1955), S. 388-388 
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    Journal of Polymer Science 18 (1955), S. 389-392 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
    Notes: Squalene was treated with benzoyl peroxide and isoprene-dialcohol dibenzoate was isolated. It is now proved for the first time that the molecule of polyisoprene was decomposed by a free radical and the location of the scission was the CH2—CH2 linkage.
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    ISSN: 0022-3832
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    Notes: A study of the growth of butadiene popcorn polymer seeds in the presence of styrene monomer vapor at 60° has shown the growth to be logarithmic with time. The growth appears to be independent of the peroxide content of the seeds and can be retarded by the presence of various sulfur containing compound. Oxidation of the butadiene seeds grown in styrene by air exposure destroys their activity for continued growth.
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    Journal of Polymer Science 18 (1955), S. 423-424 
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    Journal of Polymer Science 18 (1955), S. 431-435 
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    Journal of Polymer Science 18 (1955), S. 440-442 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Polymer Science 18 (1955), S. 449-454 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
    Notes: The problem of tensile failure is discussed in terms of the conditions for mechanical stability. Data are not available for detailed examination of the usefulness of this approach. However, some measurements on plasticized polyvinyl chloride, cellulose acetate, and polymethyl methacrylate suggest that the arguments may have some validity. The toughness and brittleness of materials are also considered briefly in the same terms. Attention is called to the complications that may arises from the adiabatic character of the failure process.
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    Journal of Polymer Science 18 (1955), S. 479-490 
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    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of various added simple electrolytes upon the solution viscosity of polymethacrylic acid and hydrolyzed polyacrylonitrile was studied. The viscosity behavior of these polymers in water and in the presence of added NaCl was typical of that of polyelectrolytes. The addition of multivalent anions (sulfate, diacid phosphate, oxalate, and succinate) to solutions of polymethacrylic acid decreasesd the viscosity at low added salt concentrations, but a reversal in the reduced viscosity-concentration curve was obtained as the ionic strength was increased. This increase in viscosity can be partly explained on the basis of increased ionization originating from the behavior of the added multivalent anions. However, this is not the complete explanation since the relative efficiency of these anions in increasing the viscosity is not consistent with the values of the dissociation constants. A possible alternative explanation involves the formation of associated complexes of the polyions. It is further demonstrated that the limiting intrinsic viscosities at infinite ionic strength is dependent upon the initial polymer charge.
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    Journal of Polymer Science 18 (1955), S. 515-525 
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    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerizations of styrene have been carried out in solution using as initiators benzoyl peroxide or ammonium persulfate. It has been shown that the ammonium persulfate initiated polymerizations proceed at a faster rate and produce polymers of higher molecular weight than those initiated by benzoyl peroxide, although all the conditions for polymerization remained identical in both cases. This behavior is explained in terms of a reduced rate of termination. It is suggested tentatively that the reduction in the rate of termination may be due to the mutual electrostatic repulsion of the chains caused by the presence of electrically charged end groups arising from initiation by the sulfate ion radical. Calculations are presented showing the essential conditions that have to be fulfilled to make the explanation tenable.
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    Journal of Polymer Science 18 (1955), S. 559-562 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
    Notes: Use has been made of the statistical theory of elasticity to calculate the number of crosslinks in vulcanizates that have been formulated and vulcanized in such a manner as to have the greatest number of crosslinks for the amount of sulfur present. These calculations suggest that the formation of up to 80% of the crosslinks are accompanied by the formation of a molecule of sulfide sulfur and that the crosslinks are largely, if not entirely, of the monosulfide type.
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    Journal of Polymer Science 18 (1955), S. 586-588 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
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    Journal of Polymer Science 18 (1955), S. 589-591 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
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  • 88
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Experiments were carried out as an attempt to peroxidize polystyrene and poly-p-isopropyl-styrene. The reaction proceeds with difficulty in the case of polystyrene, producing only a small yield.In the case of poly-p-isopropylstyrene, however, peroxidation proceeded as easily as with cumene. The obtained products were investigated as initiators in the polymerization of methylmethacrylate.
    Notes: Es wurden Versuche zur Peroxydation von Polystyrol und von Poly-p-isopropylstyrol ausgeführt. Diese Reaktion erfolgt bei Polystyrol sehr schwer und in geringem Umfang. Dagegen läßt sich Poly-p-isopropylstyrol ähnlich leicht wie Cumol peroxydieren. Die erhaltenen Produkte wurden auf ihre Initiatorwirkung für die Polymerisation von Methacrylsäuremethylester untersucht.
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    ISSN: 0025-116X
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    Die Makromolekulare Chemie 16 (1955), S. 74-76 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 91
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
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    Description / Table of Contents: The polymeric peroxides of dimethylbutadiene, isoprene and cyclopentadiene are thermally decomposed and the fragments analyzed. The content of 1,2-structure of the polymeric peroxide of dimethyl-butadiene is about 40-50%, of the polymeric peroxides of isoprene nearly 25%. The polymeric peroxide of cyclopentadiene has only 1,4-structure.The reaction of the polymeric peroxides with perbenzoic acid had been investigated. The presence of peroxy groups in α-position to an ethylenic bond changes their reactivity with perbenzoic acid, decreasing the reactivity of internal double bonds.
    Notes: Die polymeren Peroxyde von Dimethylbutadien, Isopren und Cyclopentadien werden thermisch zersetzt und die erhaltenen Bruchstücke untersucht. Quantitative Bestimmungen von Formaldehyde ergeben, daß das polymere Dimethylbutadienperoxyd zu 40 bis 50%, das polymere Isopreperoxyd zu etwa 25% aus 1,2-Copolymerisaten der Diene mit molekularem Sauerstoff bestehen. Das polymere Cyclopentadienperoxyd entsteht dagegen anscheinend nur durch 1,4-Addition, da der Nachweis des für ein 1,2-Copolymerisat als Zersetzungsprodukt zu erwartenden Glutaconsäuredialdehyds nicht gelang.Es wird außerdem versucht, mit Perbenzoesäure die bei 1,4-Autoxydation zu erwar-tenden kettenständigen Doppelbindungen neben den bei 1,2-Autoxydation zu erwarten-den Vinylseitenketten zu bestimmen. Die Anwesenheit einer peroxydischen Gruppe in α-Stellung zu einer Doppelbindung ändert deren Reaktionsfähigkeit mit der Persäure; sie ist bei kettenständigen Doppelbindungen vermindert.
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    Die Makromolekulare Chemie 16 (1955), S. 119-139 
    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: Durch Untersuchung der mit Benzoylperoxyd, Ditert. Butylperoxyd. Methyläthyl-keton-Peroxyd und tert. Butylhydroperoxyd initiierten Blockpolymerisation von Acryl-säuremethylester bei 55°-75°C wurden Initiierungsgeschwindigkeit und die Übertragungs-konstanten des Monomeren und der genannten Peroxyde ermittelt. Die Temperatur-koeffizienten für die Geschwindigkeitskonstanten wurden bestimmt. Ferner werden die Werte für die Initiatorwirksamkeit und für die Geschwindigkeit der thermischen Polymerisation festgestellt. Berechnete und experimentell gefundene Kettenlängen werden miteinander verglichen. Gewisse Aspekte der Polymerisation von Acrylsäuremethylester werden verglichen mit solchen der Polymerisation von Styrol und Methacrylsäuremethyl-ester.
    Notes: By a study of bulk polymerization of methyl acrylate at 55°-75°C with benzoyl peroxide, ditertiary butyl peroxide, methyl ethyl ketone peroxide and tertiary butyl hydroperoxide as catalysts, rates of initiation, chain transfer constants for the monomer and the catalyst have been evaluated. Determination of temperature coefficients for all the rate constants have been made. Values for the catalyst efficiencies and thermal rate constants for initiation are given. Calculated and experimentally determined chain lengths are compared. Certain aspects of polymerization of methyl acrylate are compared with styrene and methyl methacrylate.
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    Description / Table of Contents: Die Viskositätszahlen für normales Albumin vom Menschenblut und Albumin aus Ochsenblut wurden bestimmt. Werte zwischen 0.035-0.040 wurden gefunden für das Albumin aus Menschenblut, und 0.031-0.038 für das Albumin aus Ochsenblut. Die Unterschiede in den angegebenen Grenzen sind von dem Lösungsmittel (Ionenstärke, pH) und von der Temperature abhängig. Diese Werte, die an höchstgereinigten Proteinen gefunden wurden, sind kleiner als die von anderen Autoren früher gefundenen Zahlen. In mäßig konzentrierten Lösungen, bis zu 8 g Albumin in 100 ccm, steigen die ηsp/c-Werte linear mit der Konzentration c an. In hochkonzentrienten Lösungen kehren sich die Geraden aufwärts.
    Notes: The intrinsic viscosity of normal human and bovine serum albumin was determined. Values between 0.035-0.040 were found for human albumin, and 0.031-0.038 for bovine albumin, depending on the solvent and temperature. It was found that a linear relationship exists between the reduced viscosity ηsp/c and concentration c up to c of 8 grams albumin in 100 ml solution.
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    Die Makromolekulare Chemie 17 (1955), S. 29-38 
    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 Kettenübertragungsreaktion bei der peroxydisch initiierten Polymerisation von Acrylsäuremethylester wurde in 11 verschiedenen Lösungsmitteln untersucht und die übertragungskonstanten bestimmt. Die anomalen Ergebnisse, die im Falle von Chloroform und Tetrachlorkohlenstoff erhalten wurden, werden diskutiert. Die Fehlermöglichkeiten und Annäherungen, die bei solchen Untersuchungen gewöhnlich gemacht werden, werden kurz dargestellt.
    Notes: A study of chain transfer in catalyzed polymerization of methyl acrylate in the presence of eleven solvents has been made and chain transfer constants calculated. The anomalous results obtained for chloroform and carbon tetrachloride are discussed and sources of errors and assumptions that are usually made in such studies are also briefly reviewed.
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    Die Makromolekulare Chemie 17 (1955), S. 43-55 
    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: Es wurde eine homologe Reihe von Polyamiden aus Tetrahydrofuran-2,5-dipropionsäure und Polymethylendiaminen (Nylon nT, n = 2, 4 ∼ 10) und 2 Serien von Mischpolyamiden (Nylon 66/6T und 69/6T) hergestellt. Auf Grund von Untersuchungen der Eigenschaften dieser Polyamide wird der Einfluß des Tetrahydrofuranringes auf die Eigenschaften der Polykondensate diskutiert.Die Einführung des Tetrahydrofuranrings in die Polyamidkette hat nut wenig Einfluß auf Schmelzpunkt und Kristallinität, erhöht jedoch beträchtlich die Löslichkeit, Feuchtigkeitsaufnahme und das Farbstoffbindevermögen. Das Mischpolyamid 66/6T (Gew.-Verhältnis 4 : 1) gibt Fasern mit guten mechanischen Eigenschaften und stark verbesserter Anfärbbarkeit.
    Notes: A homologous series of polyamides from tetrahydrofuran-2,5-dipropionic acid and polymethylenediamine (nylon nT, n = 2, 4 ∼ 10) and two series of copolyamides (nylon 66/6T and 69/6T) have been prepared. Based on studies of the properties of these polymers the effects of tetrahydrofuran ring on polymer properties have been discussed.The introduction of tetrahydrofuran ring into polyamide chain has little influence on melting point and christallinity of the polymer, but fairly increases the solubility, moisture regain, and receptivity towards dyes. The copolyamide 66/6T (wt. ratio 4 : 1) gives a fibre having good mechanical properties and greatly improved dyeing properties.
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    Die Makromolekulare Chemie 17 (1955), S. 74-76 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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    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: At the reaction of N,N′-disubstituted products or monochlorhydrates of aliphatic diamines with formaldehyde in molar ratio l : l are formed in the case of ethylene- and propylene-diamine derivatives of tetrahydroimidazole and hexahydropyrimidine or the heterocycles and their linear tautomeres respectively. The higher homo-logeous diamines react either to substituted linear methylendiamines of low molecular weight or to the monomethylene-diamines, which forme the trimerics hexahydrotriazines.The structure of the reaction products of the higher diamines with formaldehyde in molar ration 1 : 2 is consequently adjudged to he cross-linked poly-bismethylene-diamines containing hexahydrotriazine rings. As the polyoxymethylene is used as a model for linar chain-polymers, so these products can be regarded as model for cross-linked macromolecular polymers.An insight into the structure of the syrupy reaction products of tetramethylenediamine is obtained by fractionation, investigation into the dependance of the change into amorphous, insoluble compounds on temperature, end-group determination with diphenylketene, as well as partial catalytic hydrogenation and viscosity measurements. The fact that also the lowest molecular constituent contained no methylol groups, speaks for a mechanism of formation through polymerization. The established high saturation rate is explained by the presence of hexahydrotriazine configurations.The crystalline reaction products of ethylenediamine and propylenediamine with formaldehyde, in molar ratio 1 : 2, are formulated as cycl.-bismethylene-di-tetrahydroimidazole, and cycl.-tetramethylene-tetra-hexahydropyrimidine, respectively. The former reaction results in the formation of isomers, one of which can be isolated as a pure substance. By partial splitting off with sulphurous acid, from these products can be obtained the N-methylenesulfonic acids of the heterocyclic rings, which are contained in the original molecules. In this way the structure can he determined.
    Notes: Bei der Reaktion von N,N′-Disubstitutionsprodukten oder Monochlorhydraten aliphatischer Diamine mit Formaldehyd in Molverhältnis 1 : 1, entstehen bei äthylen- bzw. Propylendiamin Derivate des Tetrahydroimidazols bzw. des Hexahydropyrimidins oder diese Heterocyclen resp. deren tautomere, offene Form selbst. Die höheren Homologen reagieren unter Bildung von entsprechend substituierten Methylendiaminen niedrigen Molekulargewichtes oder von Monomethylen-diaminen, von denen sich 3 Moleküle unter Bildung des entsprechenden Hexahydrotriazins absättigen.Den Reaktionsprodukten der aliphatischen Diamine mit 4 und mehr C-Atomen mit Formaldehyd im Molverhältnis 1 : 2 ist die Struktur vernetzter, Hexahydrotriazinringe enthaltender Poly-bismethylendiamine zuzuerkennen. Wie die Poly-oxymethylene ein Modell für lineare Kettenpolymere darstellen, könen diese Produkte als Modell für vernetzte Makropolymere angesehen werden.An den syrupösen Umsetzungsprodukten des Tetramethylendiamins wurde durch Fraktionierungen, Untersuchungen der Temperaturabhängigkeit des überganges in die amorphen, unlöslichen Körper, Endgruppenbestimmungen mit Diphenylketen sowie partielle katalytische Hydrierung und durch Viskositätsmessungen Einblick in die Struktur gewonnen. Die Tatsache, daß auch die niedrigsmolekularen Anteile keine Methylolgruppen enthalten, sprechen für einen Bildungsmechanismus durch Polymerisation. Der festgestellte hohe Absättigungsgrad wird mit dem Vorliegen von Hexahydrotriazinkonfigurationen erklärt.Die kristallinen Umsetzungsprodukte von äthylendiamin und Propylendiamin mit Formaldehyd in Molverhältnis 1 : 2 sind cycl.-Bismethylen-di-tetrahydroimidazol resp. cycl.-Tetramethylen-tetra-hexahydropyrimidin. Von ersterem existieren Isomere. Eines konnte rein isoliert werden. Bei dem unter partieller Aufspaltung verlaufenden Umsatz mit schwefliger Säure wurden in beiden Fällen N-Methansulfosäuren der in den Molekülen enthaltenen Heterocyclen isoliert und so der Strukturbeweis geführt.
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  • 98
    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: The kinetics of the autoxidation of methyl linoleate catalysed by means of azoisobutyronitrile, cumenehydroperoxide, tetralinhydroperoxide, cyclohexenylhydroperoxide, tert.-butylhydroperoxide, cyclohexenyl-tert.butyl-peroxide, and some further peroxides have been investigated. The evaluation of the results obtained from the individual initiators and their comparison with the kinetics of the spontaneous autoxidation of methyl linoleate show the peroxide of methyl linoleate to possess the structure of a hydroperoxide.
    Notes: Es wird die Katalyse der Autoxydation des Linolsäuremethylesters durch Azo-diisobuttersäurenitril, Cumolhydroperoxyd, Tetralinhydroperoxyd, Cyclohexenhydroperoxyd, tert.-Butylhydroperoxyd, Cyclohexenyl-tert.-butylperoxyd sowie eine Reihe weiterer Peroxyde kinetisch untersucht. Die Auswertung der bei den einzelnen Initiatoren gefundenen Ergebnisse und ihr Vergleich mit den kinetischen Beziehungen, die bei der spontanen Autoxydation des Linolsäuremethylesters beobachtet wurden, zeigt, daß dem Peroxyd des Linolsäuremethylesters eine Hydroperoxydstruktur zuzuschreiben ist.
    Additional Material: 7 Ill.
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  • 99
    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: A new viscosity-concentration relation, already employed in the first communication an approximation [1], being valid over a very large concentration range, without using supplementary or correction terms, is mathematically confirmed and analysed in detail.This relation proves to be an extension of the generalised Huggins' function [6]. The exponent appears as a new constant in this function, maintaining the intrinsic viscosity number [η] and the Huggins' constant k1. The exponent n as well as k1 are shown to be independent of the number of the polymer chain-links. After developing the new function [1] in an exponential series of c its comparableness with the hydrodynamical viscosity-concentration series is perceptible. In this series, the exponent n has at the least the importance to calculate exactly the coefficients of the terms with higher powers of c. Thus the coefficients are exclusively established by the intrinsic viscosity number [η], the hydrodynamical Huggins' constant k1 and the exponent n in [1].By this, it is confirmed that the various mechanism appearing at the experimental determination of the viscosity-concentration relations are showing gradual transitions with increasing concentration and the mutual functional connection is made probable.Two experimental series (Polyacrylonitrile and Cellite) serve as an example, illustrated by tables and diagrams.
    Notes: Eine bereits in der I. Mitteilung als Näherungsfunktion [1] verwendete neue Viskositäts-Konzentrations-Beziehung, die ohne Anwendung von Ergänzungs- oder Korrekturgliedern über einen sehr weiten Konzentrationsbereich Gültigkeit besitzt, wird ausführlich mathematisch begründet und analysiert.Sie erweist sich als eine Erweiterung der verallgemeinerten Hugginsschen Funktion [6]. Als neue Konstante tritt in dieser Funktion der Exponent n auf, unter Beilbehaltung der Grenzviskositätszahl [η] und der nach [6] ermittelten Huggins-Konstante k1.Es erweist sich, daß n ebenso wie k1 unabhängig von der Kettengliederzahl des Polymers ist. Nach Auflösung der neuen Funktion [1] in eine Exponentialreihe von c wird ihre Vergleichbarkeit mit der hydrodynamischen Viskositäts-Konzentrationsreihe erkennbar.In dieser Reihe kommt dem Exponenten n zum mindesten die Bedeutung zu, die Koeffizienten der Glieder mit höheren Potenzen von c exakt zu berechnen. Die Koeffizienten werden so ausschließlich festgelegt durch die Grenzviskositätszahl [η], durch die hydrodynamische Huggins-Konstante k1 und den Exponenten n in [1].Es ird hierdurch bestätigt, daß die bei der experimentellen Ermittlung von Viskositäts-Konzentrationsbeziehungen auftretenden verschiedenartigen Mechanismen allmähliche übergänge mit steigender Konzentration aufweisen, und ihr gegenseitiger funktioneller Zusammenhang wahrscheinlich gemacht.Als Beispiel dienen zwei Experimentalreihen (Polyacrylnitril und Cellit) erläutert durch Tabellen und Diagramme.
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  • 100
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 17 (1955), S. 154-157 
    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: The synthesis of 3 etherdialdehydes starting from p-oxybenzaldehyde and various ω,ω′-dihalogenocompounds is described. This products are used in condensations with aliphatic diamines.
    Notes: Es wird die Darstellung von 3 Ätherdialdehyden aus p-Oxybenzaldehyd und verschiedenen ω,ω′-Dihalogenverbindungen beschrieben, die zur Umsetzung mit aliphatischen Diaminen verwendet werden.
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