摘要:

AbstractThe composition and gross structural features of plasma polymer films prepared by inductively coupled RF plasmas excited in pentafluorobenzene were investigated by ESCA as a function of the operating parameters. The rate of film deposition is dependent on the W/FM parameter and on site of deposition. The polymer formed in the glow region shows only small variations in structure as a function of power and pressure. Polymer films deposited in the regions away from the site of primary excitation typically have a higher fluorine content than those formed in the coil region; the stoichiometry for the latter is comparable to that of the starting material.

ISSN:0360-6376    

DOI:10.1002/pol.1981.170190901

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractAnalysis of phenolphthalein and bisphenol‐A copolycarbonates reveals a linear correlation between oxygen index (OI) and char yield (Y):OI= 0.34Y+ 19.6, which can be compared with the empirical equationQI= 0.4Y+ 17.5 proposed by D. W. Van Krevelen for other polymers. Analysis also suggests that no chemical interction occurs between the two comonomers during pyrolysis, which leads neither to enhanced char yield nor to enhanced oxygen index. Each copolymer component contributes to the char yield and oxygen index on an additive basis. Study of 4,5,6,7‐tetrabromophenolphthalein and phenolphthalein copolycarbonates shows that some enhancement of char yield does occur and that the lower the char yield, the higher the oxygen index, which is an indication of the predominance of a vapor‐phase bromine effect over that related to char. Study of 4,5,6,7‐tetrabromophenolphthalein and bis‐phenol‐A copolycarbonates is interpreted on the basis of two factors—the char effect that prevails over the vapor phase radical scavenging effect at lower bromine content and the reverse order at higher br

ISSN:0360-6376    

DOI:10.1002/pol.1981.170190902

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe cyclopolycondensation of linear bis‐β‐diketones with aromatic dihydrazines in dimethyl sulfoxide at 100–150°C produced a series of aromatic polypyrazoles with inherent viscosities up to 0.6 dL/g. All the polymers were highly soluble in a wide range of solvents, which included tetrahydrofuran and chloroform. The polypyrazoles showed excellent thermal stability with 10% weight loss at 410–490°C in air and nitrogen

ISSN:0360-6376    

DOI:10.1002/pol.1981.170190903

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractNew polythioesters by interfacial polycondensation of 4,4′‐di(mercaptomethyl) benzophenone with oxalyl, succinyl, adipoyl, suberoyl, and sebacoyl chlorides were obtained. To determine the optimal conditions for interfacial polycondensation the influence of the following factors on yield and value of reduced viscosity were studied: type of organic phase, the quantitative ratio of aqueous and organic phase, concentration of hydrogen chloride acceptor, molar ratio of reagents, temperature of reaction, rate of acid chloride addition, and contribution of catalyst and emulsifier. A thorough examination was carried out only for polycondensation of dithiol with adipoly and sebacoyl chlorides. The structure of all polythioesters obtained under the model conditions was determined by elementary analysis and infrared spectra. Initial decomposition and initial intensive decomposition temperature were defined from the curves of thermogravimetric analysis. Some mechanical and electrical properties of the polythioesters obtained from 4,4′‐di(mercaptomethyl)benzophenone and adipoyl and sebacoyl chlorides were determined. The molecular weight was not measured because of the low solubility of the obtained polythi

ISSN:0360-6376    

DOI:10.1002/pol.1981.170190904

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractIn this work a study is made of the degradation on ozonation of unfractionated polystyrene (PS) in CCl4solution. It was found that the ozone attack of PS molecules is accompanied by hydrogen abstraction from tertiary CH bonds and by the formation of ozonides due to the reaction of ozone with the aromatic rings. A scheme of PS degradation in solution is suggested; several kinetic parameters are evaluated.

ISSN:0360-6376    

DOI:10.1002/pol.1981.170190905

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe polymerization of cyclohexene oxide was investigated with a new catalyst system of Al(acac)3‐ silanol compounds. Catalyst activity varied with the ratio of silanol/Al(acac)3and the structure of silanol compounds. Catalyst deactivation appeared to be caused by self‐condensation of silanol and the addition of silanol to the epoxy ring. Polymer structure was investigated by13C‐NMR spectroscopy and x‐ray diffraction. The mechanism of the polymerization appears to be c

ISSN:0360-6376    

DOI:10.1002/pol.1981.170190906

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe titrations of the polyammamides prepared from adipic acid and diethylenetriamine or di(3‐aminopropyl)methylamine were monitored by means of natural‐abundance15N‐(NMR) nuclear magnetic resonance spectra. Opposite shift effects were found for amine and amide nitrogens upon protonation of the amino groups. These shift effects allow one to distinguish substitutions involving exchange of electric charges from other substitutions without isolation of the polymers. Reactions of the polyaminamides with β‐propiolactone, γ‐butyroslution, methyl‐methane sulfonate, prolyleneoxide, epichlorohydrine, maleic acid anhydride, succinic acid anhydride, carbon dioxide, ethylchloroformate, and methyne sulfonylchloride were carried out in water, and the resulting polyelectrolytes were characterized by means of15

ISSN:0360-6376    

DOI:10.1002/pol.1981.170190907

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractNew graft copolymers were synthesized by grafting hydroxyethyl methacrylate and hydroxpropyl methacrylate on poly(vinyl alcohol) in aqueous solution with Ce+4ions as initiator. The dependence of the percentage of grafting and monomer conversion on the concentration of the monomer, on the concentration of the initiator, on the total concentration of the reactants, and on temperature and duration of the reaction were investigated. Some basic properties of the graft copolymers and some preliminary permeation measurements of water vapors through films, made from these copolymers, are also reported.

ISSN:0360-6376    

DOI:10.1002/pol.1981.170190908

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractModel graft copolymers were synthesized by grafting acrylamide onto dextran (Mw= 500,000) utilizing an initiation method in which a Ce(IV)/HNO3solution was added to the dextran solution in order to allow coplexation prior to monomer addition. Three synthetic reaction parameters were optimized on the basis of conversion and solution viscosity: monomer concentration, dextran concentration, and nitric acid concentration. Molar ratios of [Ce(IV)]/[dextran]were changed systematically to affect the number and length of the acrylamide grafts. The number of grafting sites and graft chain lengths, determined by selective hydrolysis of the carbohydrate backbone, were in good agreement with those theortically predicted from knowledge of initiation efficiency and monomer conversion. Rheological studies of the model graft copolymers were conducted in aqueous solutions as a function of temperature, added salt, and copolymer concentration.

ISSN:0360-6376    

DOI:10.1002/pol.1981.170190909

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe amine catalyzed isomerization of itaconic to citraconic anhydride has been investigated. Studies show that the rate of isomerization is dependent on the base strength and solvent media. Triethylamine causes complete isomerization within 5 min at room temperature in acetone or chloroform solvent, whereas aromatic tertiary amines such as pyridine andN,N‐dimethylaniline require time perods as long as 23h at room temperature for almost complete isomerization. In the presence of aniline no isomerization occures even under acetone reflux conditions over a 24 h period. For the preparation of citraconamic acids from itaconic anhydrides and aliphatic diamines nuclear magnetic resonance and infrared spectroscopic evidence is presented to support the reaction path of initial isomerization of itaconic anhydride to citraconic anhydride followed by amine attack on the anhydride to form the correspondingcis‐citraconamic acids. The mechanism of isomerization of itaconic to citraconic acids is propo

ISSN:0360-6376    

DOI:10.1002/pol.1981.170190910

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY