摘要:

Kinetics of the polymerization of methyl methacrylate has been investigated in aqueous sulfuric acid in the temperature range of 35–50°C in the presence of the redox system V5+/thioaceta-mide. The rate of polymerization and the rate of V5+ion disappearance have been measured. The effect of various additives such as water-miscible organic solvents, neutral electrolytes, complex-ing agents, and solvent composition on the rate have been thoroughly studied. A mechanism involving the initial complex formation between the thiol form of the thioacetamide and V5+, whose decomposition yields the initiating free radical, with the polymer chain terminated by metal ion has been suggested.

ISSN:0022-233X    

DOI:10.1080/00222338108074386

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The vinyl polymerization of acrylonitrile initiated by the redox system Mn3+-glucose has been studied in aqueous sulfuric acid at 30–50°C. The rate of polymerization, the rate of Mn3+disappearance, etc. were measured. The effect of certain water miscible organic solvents, inorganic salts, dyes, solvent composition, solid substances, and inhibitors on the rate of polymerization has been investigated. Based on the experimental results, a suitable reaction mechanism involving the formation of a complex between Mn3+and the substrate molecule, whose decomposition yields the initiating free radical with the polymer chain being terminated by the mutual combination of growing chains, has been suggested.

ISSN:0022-233X    

DOI:10.1080/00222338108074387

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The kinetics of the reaction of “living” poly-α-methylstyrene with t-butyl chloride has been studied spectrophotometrically in dioxane for the counterions sodium and potassium. The reactions are found to be precisely first-order with respect to both species. The Arrhenius parameters are determined for the overall ion-pair reaction with t-butyl chloride; the living ends have been shown to exist largely in the form of contact ion-pairs. The gaseous products of the reactions are quantitatively estimated by GLC analysis, and in the case of the sodium-initiated system, Arrhenius parameters are recovered for the elimination reaction. A tentative mechanism is advanced to explain the kinetic data.

ISSN:0022-233X    

DOI:10.1080/00222338108074388

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The formation of ether linkages in polyethylene terephthalate was investigated using three different metal acetates as catalysts. The zinc salt was found to produce more ether bonds than either lead(II) or manganese(II) acetate. The amount of diethylene glycol detected in the fibers increased with rising catalyst concentration as well as with increasing polycondensation time. Negligible at the reesterification temperature of 195°C, ether formation became more important during the preheating period during which the polycondensation temperature was achieved (280°C). Most of the ether linkages were formed during the first 30 min of polycondensation and only a slow increase was observed thereafter. Model experiments conducted by heating pure ethylene glycol with the catalysts were in agreement with the polycondensation results.

ISSN:0022-233X    

DOI:10.1080/00222338108074389

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Gelatin was graft copolymerized with poly(butyl acrylate) using potassium peroxy disulfate in aqueous medium. Effects of temperature, time, monomer concentration, and backbone concentration were studied. The percent grafting was found to increase initially and then decreased in all cases. Infrared, viscosity, and thermal analysis were carried out on the graft copolymers, and the mechanism of the graft copolymerization reaction was discussed.

ISSN:0022-233X    

DOI:10.1080/00222338108074390

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0022-233X    

DOI:10.1080/00222338108074375

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor