ISSN:0022-3832    

DOI:10.1002/pol.1954.120137101

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractThe effect of temperature and pH on the optical rotation of a representative group of proteins was investigated. It was found that the proteins showed little or no effect of temperature on the optical activity whether in the native or denatured state. Where definite changes in rotation occurred among the native proteins, these were attributed to denaturation accompanying the change of temperature. Zein, casein, fibrin, erepsin, globin, native and denatured egg and serum albumins, edestin, and pepsin showed no temperature dependence of optical rotation, over the temperature range 20 to 60°C., although protamine sulfate and gliadin possessed small negative coefficients. Native chymotrypsin, trypsin and β‐lactoglobulin showed a marked increase in levorotation with increase of temperature, which was due to denaturation on heating. The denatured forms of the latter two proteins, however, showed no change of optical activity with temperature. The shapes of the optical rotation‐pH curves obtained for salmine, zein, gliadin, egg and serum albumins, casein, fibrin, and insulin were found to reflect the presence of free acid‐ and base‐combining groups in the proteins, with some uncertainty in the case of globin. Since native pepsin, trypsin, chymotrypsin, and β‐lactoglobulin were denatured at pH values not far from those of their normal aqueous solutions, the rotation‐pH curves for these proteins were not capable of similar analysis, but they could be used to follow polarimetrically the course of th

ISSN:0022-3832    

DOI:10.1002/pol.1954.120137102

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractThe rate of ultrasonic degradation of polystyrene in benzene solution saturated with a number of gases was studied. The rate of degradation decreases with increasing solubility of the gas. Ultrasonic degradation is discussed generally on the basis of a theory for ultrasonic cavitation. A rate equation for this type of degradation is proposed. It is concluded that ultrasonic degradation is mechanical in its origin due to the adiabatic collapse of cavities.

ISSN:0022-3832    

DOI:10.1002/pol.1954.120137103

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

ISSN:0022-3832    

DOI:10.1002/pol.1954.120137104

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractThe scattering of light by solutions of a well‐fractionated sample of polymethyl methacrylate in acetone, methyl ethyl ketone, and benzene, have been measured using 4358 and 5461 A. wave lengths as incident radiations. The average molecular weights of the polymer from turbidity measurements and lengths determined from angular dissymmetries of scattered light are 571,000 and 760 A. in acetone, 38,400,000 and 715 A. in methyl ethyl ketone, and 408,000 and 375 A. in benzene. The abnormal molecular weight observed in methyl ethyl ketone solution may be ascribed to low μ – μ0value of the medium. The greater molecular extension in ketone than in benzene solutions is explained in terms of the relative magnitudes of solute‐solvent interaction. The depolarization ratios ρu, ρvand ρhhave been measured and the decrease of ρvand ρhwith increase in concentration of the polymer in ketonic solvents and little change under similar conditions in benzene, are discussed in the light of the “molecular field e

ISSN:0022-3832    

DOI:10.1002/pol.1954.120137105

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractA comparative study of the unit cell parametersa,c, and β of a considerable number of cellulose specimens including samples of the four structure types cellulose I, II, III, and IV has been carried out using an evacuated camera. Small variations were observed as between samples of different origin for cellulose I and cellulose II and were most marked in the monoclinic angle parameter β and in the case of cellulose I (bacterial cellulose β = 98.25°, ramie β = 96.5°). No unit cell parameter differences greater than the experimental error were found for cellulose III, but the intensity of the (020) reflection showed large varia

ISSN:0022-3832    

DOI:10.1002/pol.1954.120137106

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractThe infrared spectra of synthetic poly‐1‐phenyl‐ and poly‐2‐phenylbutadienes have been examined, principally in the region from 9 to 15 μ. The different intramolecular structures of these polymers, corresponding to the different types of monomer additions (1,4, 1,2, and 3,4) were examined by this method; the data are in complete agreement with the chemical results as reported previously. The influence of the method of polymerization on the internal structures of the polymers is taken in evidence; the presence of the aromatic substituent in position 1 or 2 in the monomer molecule exerts a large influence on the position and the intensity of the characteristic absorption bands, if they are compared with the results for synthetic pol

ISSN:0022-3832    

DOI:10.1002/pol.1954.120137107

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

ISSN:0022-3832    

DOI:10.1002/pol.1954.120137108

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractHeating rubber‐carbon black mixtures at elevated temperatures results in vulcanizates with lower electrical conductivity, lower hysteresis, lower Durometer hardness, and increased abrasion resistance. These changes are apparently the result of chemical reactions between carbon black and rubber which alter the dispersion of the carbon black. Data are presented which show that the basic factors effecting these changes are the chemical reactivities of the carbon black and the polymer and the time and temperature of treatmen

ISSN:0022-3832    

DOI:10.1002/pol.1954.120137109

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractAn electrolytic theory is developed for the swelling and deswelling mechanism of mechanochemical systems by methods established by the authors, who are concerned with the problem of polyelectrolyte solutions. The model employed in the theory is a macroscopic cylindrical fiber of rubberlike material with many dissociative radicals. It is assumed, for the sake of simplicity, that the average charge density of the ionized radicals is spread uniformly inside the fiber. The result of the theory shows that almost all the gegenions are bound by the fiber, and that the contributions of the electrostatic energy and entropy to the electrostatic free energy are two‐ and three‐dimensional, respectively, when the density of the ionized radicals remains constant. In combination with theoretical results of rubberlike elasticity and of nonelectrolytic swelling, it is concluded that the osmotic pressure of the gegenions bound by the system makes the system swell against the restoring force due to the rubberlike elasticity of the system. The free swelling of systems is, for instance, expressed by the following relation:\documentclass{article}\pagestyle{empty}\begin{document}$$ \alpha ^2 B = N\xi $$\end{document}where α is the relative elongation,Nthe number of the dissociative radicals per chain ξ the degree of neutralization, andBthe factor due to the full stretching effect of each chain. This relation is in good agreement with experimental re

ISSN:0022-3832    

DOI:10.1002/pol.1954.120137110

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY