摘要:

Esterification of dianol 22 by means of thioglycolic acid and some analytical tests of the product obtained were carried out. The synthesis of polyurethanes was then carried out using 4,4′-diphenylmethane diisocyanate and Desmodur L. The products of polyaddition were subject to some physicomechanical, thermal, and dielectric tests.

ISSN:0022-233X    

DOI:10.1080/00222338208066476

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Graft copolymerization of methyl methacrylate onto nylon 6 was investigated in aqueous perchloric acid medium using thallium(III) ions as initiator. The rate of grafting was evaluated by varying the concentrations of monomer, initiator, acid, and temperature. The rate of grafting was found to increase with an increase of both monomer and initiator concentrations. The graft yield was found to increase with an increase in the acid concentration up to 0.49 mL−1, and beyond this concentration of perchloric acid the graft yield was found to decrease. It also increased with an increase of temperature. From the Arrhenius plot the overall activation energy was found to be 3.9 kcal/mol. The effects of inhibitors, various solvents, inorganic salts, and swelling agents on graft yield were studied. A suitable kinetic scheme has been proposed and a rate equation has been derived.

ISSN:0022-233X    

DOI:10.1080/00222338208066477

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The radical copolymerization of styrene (St, M1) with 3(2-methyl)-6-methylpyridazinone (I, M2) has been carried out in several p-substltuted phenols at 60 and 70°C. Monomer reactivity ratios (r1) and activation parameters of copolymerization were found to be affected by phenols. The values of the activation energy (δδE‡) and entropy (δδS‡) increased with the increase of the interaction of I with the solvents. Linear relationships were observed between the [sgrave]-values of p-substituents of phenols and the values of log 1/r1and also of δδE‡ and δδS‡. The radical copolymerization of St (M1) with 6-substituted 3(2-methyl)-pyridazinone was also carried out.

ISSN:0022-233X    

DOI:10.1080/00222338208066478

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Ultrasonic (20 kHz, 70 W) solution degradations of polystyrene, substituted polystyrenes, and poly(n-vinyl carbazole) have been carried in toluene and tetrahydrofuran at 27 and -20°C in the presence of flexible chain polymers. Polystyrene formed block copolymers at 27°C with stiff-chain polymer PVCz; however, in the presence of flexible chain polymers, e.g., poly(vinyl methyl ketone) or poly(vinyl methyl ether), there were no block copolymers formed. Poly(n-vinyl carbazole) does not seem to form any block copolymers at 27°C with flexible chain polymers, e.g., poly(octadecyl methacrylate) and poly(ethyl methacrylate). Poly(p-chlorostyrene) and poly(p-methoxystyrene) also do not form block copolymers at 27°C with poly(octadecyl methacrylate) but do so with poly(hexadecyl methacrylate). It is quite possible that these may only be blends of two homopolymers. Poly(octa-decyl methacrylate) does yield a block copolymer when sonicated at -15°C with poly(p-isopropyl α-methylstyrene).

ISSN:0022-233X    

DOI:10.1080/00222338208066479

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Kinetics of vinyl polymerization of acrylonitrile initiated by the redox system Mn(III)/ethane thiol were investigated in aqueous sulfuric acid in the temperature range of 30-45°C. The rate of polymerization, rate of manganic ion disappearance, etc. were measured. The effect of certain water-miscible organic solvents, neutral electrolytes, and organic nitrogen compounds on the rate has been investigated. A mechanism involving the formation of a complex between Mn(III) and the thiol, whose decomposition yields the initiating free radical with the polymerization being terminated by mutual combination of the growing radicals, has been suggested.

ISSN:0022-233X    

DOI:10.1080/00222338208066480

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A new poly(organophosphazenes) copolymer was formed from the reaction of aminopentafluoroethoxycyclotriphosphazene, sodium phenoxide, and poly(dichlorophosphazene). The polymer was thermoplastic and the Tgincreased with an increasing amount of the phenol group. The Tgof the polymer with aminopentafluoroethoxycyclotriphosphazene attached as a pendant group was similar to the Tgof polyfluoroethoxyphosphazene.

ISSN:0022-233X    

DOI:10.1080/00222338208066481

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The polymerization of styrene (St) initiated by 1,4-dimethyl-1,4-bis(p-anisyl)-2-tetrazene (1a) was studied kinetically in benzene. The polymerization proceeds through a radical mechanism. The rate of polymerization is proportional to [1a]0.5and [St]1.0. The overall activation energy for the polymerization is found to be 81.2 kJ/mol within the temperature range of 65 to 80°C. The activation parameters for the decomposition of1aat 70°C are kd= 1.88 × 10−5s−1, δH‡ = 133.1 kJ/mol, and δS‡ = 29.9 J/mol·deg.

ISSN:0022-233X    

DOI:10.1080/00222338208066482

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The kinetics of the aqueous polymerization of acrylonitrile initiated by the peroxydiphosphate-thioacetamide redox system was investigated at 35, 40, and 50°C. The rates of polymerization were measured at different concentrations of oxidant, activator, and monomer. Peroxydiphosphate alone did not initiate polymerization under deaerated and undeaerated conditions. Addition of certain water-miscible organic solvents and neutral salts depress the rate and conversion. On the basis of experimental observations of the dependence of the rate of polymerization on various variables, a suitable kinetic scheme has been proposed.

ISSN:0022-233X    

DOI:10.1080/00222338208066483

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Z,Z-2,4-Hexadienedinitrile, synthesized by the oxidative cleavage of o-phenylenediamine, was found to undergo anionic polymerization with n-BuLi in DMF at room temperature or below. The polymerization behavior appears to be similar to that of acrylonitrile polymerization using n-BuLi as initiator. Infrared and NMR analysis of the polymer indicate the presence of both 1,4 and 1,2 linkages, with the latter predominating.

ISSN:0022-233X    

DOI:10.1080/00222338208066484

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The photoinduced graft copolymerization of methyl methacrylate onto cellulose was studied using N-bromosuccinimide as the photoinitiator. The formation of graft copolymer increases with an increasing amount of cellulose. The graft copolymerization increases with increasing initiator concentration up to 1,25 × 10−2Mand thereafter it decreases. The percentage of graft increases with increasing monomer concentration up to 46.9 × 10−2Mand thereafter it decreases. The percentage graft-on increases with increasing temperature. The overall activation energy was computed to be 8.40 kcal/mol. The percentage graft was investigated using different water-miscible organic solvents. The graft copolymerization was also investigated using differently modified cellulose. A possible mechanism for the photo-graft copolymerization onto cellulose is suggested.

ISSN:0022-233X    

DOI:10.1080/00222338208066485

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor