摘要:

AbstractThe chemical structure of a large number of linear condensation polymers is correlated with their ability to assume a polycrystalline form possessing the right degree of thermal stability, and with the possession of fiber‐forming properties. Certain structures lead to the absence of crystallinity and of fiber‐forming properties, while, under certain conditions, a low degree of crystallinity or its complete absence leads to polymers possessing rubberlike properties, which may form highly elastic threads. Some properties of fibers such as solubility, sensitivity to mositure, and certain dyeing characteristics, can be correlated to some extent with chemical structure. These effects are considered on the basis of the introduction of various polar links and ring structures, according to regular patterns, into the polymethylene chain (polythee). The ehter (RO) and ester (CO·O) links lower the crystallite melting point to such an extent that some polymers containing them are completely noncrystalline at normal room temperatures. Urethan (O·CONH), amide (CO·NH) and urea (NH·CO·NH) links raise the crystallite melting point to an extent which increases in the order named. Most other polar links raise the melting point. The introduction into the aliphatic chain of ring structures, particularly aromatic rings directly attached to polar groups, raises the crystallite melting point, but in this case symmetry exerts an over‐ruling effect. A low degree of symmetry may lower the melting point and even eliminate crystallinity entirely to the detriment of fiber‐forming properties. Inert side chains lower the melting point considerably, and in some cases render the polymer completely noncryst

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030501

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractAn empirical method of correcting the sedimentation constant of high polymers for its concentration dependence is proposed. It should be possible to determine the sedimentation constant at infinite dilution with reasonable accuracy from experiments at concentrations where reliable measurements can be made.

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030502

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractBy denaturation of potato albumin by pyridine or by heat the viscosity increases; simultaneously the capability of the denatured protein t o reduce iodine increases, which, according to Anson, is due to the liberation of SH groups. A similar increase of viscosity was observed by the conversion of legumin into a water‐soluble modification, and further by heating the solution of this protein; the volume of iodine required for oxidation of the denatured protein is greater than that of the native legumin. This denatured protein can be reconverted into its native state, whereupon the reducing capacity again decreases. Several fractions of green pen and horse bean legumin were denatured by urea and it was found that the viscosity and the reducing capacity thereby increase. In the case of legumelin the viscosity is low but the reducing power high; this indicates that legumelin is a degradation product having globular molecule

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030503

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractPolymere Oxydationsprodukte des Indens verhalten sich in Bezug auf Polymerisationsreaktionen wie typische Peroxyde. Ihre verhältnismässig hohe Stabilität bedingt eine relative geringe Reaktionsbeschleunigung, wobei Bruchstücke des zerfallenden Peroxyds in die polymere Molekel eintre

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030504

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030505

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractA refractometric technique for determination of second‐order transition temperatures (Tm) of polymers has been extended to include a series of alkyl acrylate and methacrylate polymers with transitions at temperatures down to −50°C. A convenient technique for determining refractive index down to −75°C. is described. Certain long‐chain alkyl polymers are birefringent belowTm. Correlations of brittle point withTmand relations between viscosity andTmare

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030506

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractIt has been demonstrated that the adhesion of high polymers to cellulose is a function of tack temperatures and dielectric constants, ϵ, of the polymers and of dipole moments, μ, of polar groups. A plot of tack temperature versusmirror image force, μ1μ2/,of copolymers gives an area of adhesion bounded by a tack temperature of 100% and mirror image forces of 0.7 and 1.3 and opening toward lower tack temperatures. Outside of the area polymers do not adhere well to cellulose. By coating polymers on cellulose pretreated with Werner chromium complexes of acids bearing polar groups, it has been found that adhesion is a specific function of the polar groups within the polymer and on the modilied cellulose. Adhesion is strongest with approximately equal dipole moment substituents on the modified cellulose and in the copolym

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030507

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractThe Verdet constants of nine polyethylene glycols, three polypropylene glycols, and nine silicone polymers have been measured at 25°C. It was found that the Verdet constant increases with increase in molecular weight in each of the series, and approaches a constant value. A similar increase in the molecular magnetic rotation was noted. The results are in contrast with those on polystyrene, and the effect of end groups on the measurements is discussed in explanation

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030508

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractThe relaxation of stress in polyisobutylene whole polymer of different average molecular weights has been investigated over the temperature range 30–100°C., and at different elongations. The shape of the relaxation curve is independent of elongation in a range of low elongations; above this range there is a gradual change in curve shape with increasing elongation. The shape of the relaxation curve for a given molecular weight is the same at different temperatures, when plotted as reduced stressvs.logarithmic time; a change in temperature essentially shifts the position of the curve along the logarithmic time scale. The activation energy for relaxation, calculated by use of the Arrhenius equation, is found to be independent of molecular weight in the molecular weight range investigated (M̄v= 665,00.0 to 1,420,000), the average value being 15.4 kcal. Straight lines are obtained when reciprocal viscosity‐average molecular weight is plotted against log time required for the reduced stress to reach a certain arbitrary value, at a fixed temperature and elongation. Relaxation rate depends on molecular weight with sufficient sensitivity so that relaxation measurements may be a practical method of measuring molecular weight directly in the solid

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030509

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY

摘要:

AbstractThe peroxide‐initiated polymerization of allyl methacrylate has been examined in the presence of certain additives. By the use of mercaptans and diisopropyl dixanthogen the extent of polymerization at the point where gelation occurs may be extended from about 6% to 20–30% polymerization. Examination of samples of polyallyl methacrylate, polymethyl methacrylate, and the copolymer of methyl methacrylate and allyl chloroacetate indicates that the postponement of gelation results largely from diminution of the molecular weight by the regulators. The effects of regulators on the composition of copolymers and the molecular weight of polymers, and the relation between molecular weight and extent of reaction at the gel point are discus

ISSN:0022-3832    

DOI:10.1002/pol.1948.120030510

出版商:Interscience Publishers, Inc.    

年代:1948

数据来源: WILEY