摘要:

AbstractThe sorption of acetone and water by cellulose nitrate from mixtures of the two solvents was studied by allowing the solid cellulose nitrate to come to equilibrium with aqueous solutions of acetone and measuring the change in concentration of the liquid phase. Changes in concentration were determined by measuring the index of refraction using a dipping refractometer. The values calculated for acetone sorbed per (C6) mole of cellulose nitrate are a function of the acetone concentration of the equilibrium solvent. Moles of water sorbed by one (C6) mole of cellulose nitrate depend inversely on the equilibrium acetone concentration of solvent.

ISSN:0022-3832    

DOI:10.1002/pol.1954.120147401

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractWith rhodamine‐B used as an indicator, the relative acidities of selected phenols and alcohols as model hydrogen donors have been determined in toluene solution. The method involves measurement of the change from colorless rhodamine to the colored zwitterionic form produced by the hydrogen donor compound. The method has been applied to the determination of equilibrium constants for the interaction of phenol with dimethyl formamide, benzyl acetate and dioxane; the measured constants are in accord with those obtained for the same pairs by Flett (J. Soc. Dyers Colourists,68, 59–64 (1952)), who employed infrared analysis. Consideration is given to partition of the dye between toluene and water, as influenced by hydrogen bonding and by nonelectrostatic interactions. Forces of interaction which tend to bind the dye in one phase decrease its activity in that phase and consequently reduce its tendency to move from this phase to the other. With incorporation of propiolactone polymer into the wool fiber, the activity of the dye in the fiber is reduced in relation to nonpolar as well as to aqueous solutions, and the modified wool exhibits greatly improved dyeing properties. The dye is useful also for the determination of critical micellar concentration of fatty acid soaps in aqueous solution. It also shows markedly increased binding by heat‐denatured as compared with native egg albumin, and by acetylated, as compared with normal,

ISSN:0022-3832    

DOI:10.1002/pol.1954.120147402

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractThe 25% w/w solutions of blends of cellulose acetate fractions have higher viscosities than solutions of single fractions of the same average intrinsic viscosity. It was found that the viscosity of a blend can be related to its composition by the relationship:\documentclass{article}\pagestyle{empty}\begin{document}$[\bar \eta ]_{25\%} = \frac{{\sum {[\eta ]_i^{1.4} } }}{{\sum {[\eta ]_i^{0.4} } }}$\end{document}where\documentclass{article}\pagestyle{empty}\begin{document}$[\bar \eta ]_{25\%}$\end{document}is the apparent intrinsic viscosity of the cellulose acetate blend in solution at 25% concentration, and [η]iare the intrinsic viscosities of the components. By application of this equation it was determined that only a portion of the high anomalous viscosity of solutions of cellulose acetate prepared from viscose grade wood pulp could be attributed to intrinsic viscosity distribution

ISSN:0022-3832    

DOI:10.1002/pol.1954.120147403

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractWhen a solution of natural rubber hydrocarbon is cold vulcanized with sulfur monochloride, a gel is formed. The rate of gel formation is used to characterize the rate of reaction between rubber and sulfur monochloride and a preliminary kinetic investigation is described. It is shown that the reaction is accelerated by compounds normally used for speeding up sulfur (hot) vulcanization, and it is suggested that these function by virtue of their possessing an active hydrogen atom. Several series of simple compounds, containing the groups SH, OH, and NH2, are shown to function as effective accelerators and their activity is attributed to the presence of a labile hydrogen atom in the molecule RXH, where R = organic radical and X = S, O, or N. The absence of a direct relationship between accelerating power and basic or acidic strength suggests a free radical mechanism of accelerator action, based upon the process${\rm R} - {\rm X} - {\rm H } \to {\rm R} - \mathop {{\rm X }}\limits^ * {\rm + }\mathop {{\rm H }}\li

ISSN:0022-3832    

DOI:10.1002/pol.1954.120147404

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to follow by i.r. analysis double bond shifts and chemical modification of natural rubber. Accurate determination of the original rubber spectrum is facilitated by the use of an internal standard. Isorubber, prepared by thermal dissociation of rubber hydrochloride, contains about 50% of double bonds in the side groups. Although a similar double bond shift is observed in the cyclization of rubber, part of the absorption, in the 11 μ region, may here be due to ring formation. Vulcanization with accelerated sulfur mixtures does not produce changes in the i.r. spectrum, unless the rubber is transformed into a derivative by overcuring with S2Cl2or during hard rubber formation. At least three types of oxidation reactions can be distinguished spectroscopically: (1) degradation of the rubber (by oxidation of a rubber solution with air) with the ultimate formation of only volatile oxidation products; (2) gradual formation of oxygenated derivatives (oxidation with ozone), with a distinguishable structure in the spectrum; (3) gradual formation of an oxidized and more saturated rubber (oxidation of solid rubber with air), with less characteristic broad absorption bands

ISSN:0022-3832    

DOI:10.1002/pol.1954.120147405

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

摘要:

AbstractFor the description of the practical properties of a large number of linear polymer molecules as well as for the discussion of the various mean parameters of the individual chain molecule, the model usually employed to represent the molecule consists ofNmstraight line chain elements of lengthAmstatistically joined to each other (straight element model). For the construction of large‐scale wire models of polymer molecules to be used in model experiments on the hydrodynamic behavior of chain molecules, a somewhat different model (circular segment model) was employed in previous papers. In these papers the relationships connecting the parameters which characterize these two models respectively have been determined on the basis of certain assumptions. These assumptions, as has recently been shown, were however partly in error and certain corrections have now to be applied to the numerical constants which appear in previously published formulas for the diffusion and sedimentation constants and for the intrinsic viscosity and streaming birefringence. The formulas, resulting after these corrections have been incorporated, are compiled in the present paper and the effect of these corrections on the interpretation of both new and old experimental results is discussed. It is found that agreement between theory and experiment is improved by the use of the corrected expressions and that in particular certain discrepancies which had previously existed between the lengthsAmof the statistical chain element as calculated from sedimentation and diffusion experiments, on the one hand, and viscosity determinations on the other, disappear after these corrections are applied (see Table I

ISSN:0022-3832    

DOI:10.1002/pol.1954.120147406

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

ISSN:0022-3832    

DOI:10.1002/pol.1954.120147407

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

ISSN:0022-3832    

DOI:10.1002/pol.1954.120147408

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

ISSN:0022-3832    

DOI:10.1002/pol.1954.120147409

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY

ISSN:0022-3832    

DOI:10.1002/pol.1954.120147410

出版商:Interscience Publishers, Inc.    

年代:1954

数据来源: WILEY