摘要:

AbstractThe distribution of the monomer vinyl acetate between an aqueous phase and its polymer (the latter in the form of a latex) has been measured at 20 and 40°C. The diameter of particles in a fine poly(vinyl acetate) latex has been measured in the presence of various concentrations of monomer in the aqueous phase, by means of the analytical ultracentrifuge. Comparison of the diameters so measured with those calculated from the distribution data show quite reasonable agreement (<3.7%)

ISSN:0449-296X    

DOI:10.1002/pol.1970.150080211

出版商:John Wiley&Sons, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe polymerization of aqueous solutions of vinyl acetate initiated by K2S2O8, has been studied in the presence of different concentrations of a fine “seed” latex, both in the absence and in the presence of a surfactant (sodium hexadecyl sulfate). Both kinetics and final latex size were measured, the latter showing whether fresh nucleation had occurred or not. The results suggest that surfactant adsorbed on the latex surface greatly influences the capture, by the latex surface, of oligomers formed in the aqueous phase and this, in turn, markedly affects both nucleation and kinetics. The number of free radicals per particle does not appear to be constant even with the finest particles used (ca. 50

ISSN:0449-296X    

DOI:10.1002/pol.1970.150080212

出版商:John Wiley&Sons, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractPoly(ester‐acetals) have been prepared from isopropylideneglyceryl azelaaldehydate dimethyl acetal and from methyl azelaaldehydate glycerol acetal. Acid hydrolysis of isopropylideneglyceryl azelaaldehydate led to oligomeric poly(ester‐acetals) with six to seven repeating units and carboxylic acid endgroups from which the sodium salt and the methyl ester could be prepared. The polymer sodium salt showed some surfactant properties. Methyl azelaaldehydate glycerol acetal, a mixture of geometric and structural isomers, was polymerized under typical polyesterification conditions. Lime was the best catalyst found. Molecular weights of 5000 to 12000 were obtained. Some of these polymers contained significant quantities of calcium as the carboxylate salt. A tough elastomer was prepared by heating a poly(ester‐acetal) withp‐toluenesulfonic acid and zin

ISSN:0449-296X    

DOI:10.1002/pol.1970.150080213

出版商:John Wiley&Sons, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe glycerol acetal of methyl azelaaldehydate is an ω‐hydroxy ester that exists as a mixture of dioxolanyl and dioxanyl isomers, each having two geometric isomers. Each of the four isomers was isolated by chromatographic (gas–liquid and column) and fractionating (crystallization and distillation) methods. Structural assignments were made on the basis of nuclear magnetic resonance and infrared spectral data. Linear poly(ester‐acetals) were prepared from each of thecisandtransforms of the dioxanyl isomers and from a mixture of the dioxolanyl geometric isomers. Physical properties of these polymers were correlated with their structures. When prepared with basic condensation catalysts, the polymers retained the geometric configuration and structural identity of the monomer. When prepared with lead acetate, structural rearrangement as well as polycondensation occurred, resulting in an enrichment of the dioxolanyl isomer and simultaneous increase in polymer crystallinity. The enrichment took place at elevated temperatures and also, unexpectedly, at room temperature upon long standing of the polymer. Isomer redistribution at room temperature appears to be antithermodynamic in the reaction sense, yielding a polymer of unusually high dioxolanyl unit content. The driving force for this isomerization may be crystallization of these units by a phenomenon termed a “crystallization‐induced

ISSN:0449-296X    

DOI:10.1002/pol.1970.150080214

出版商:John Wiley&Sons, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractA study of the polymerization of vinyl monomers with binary systems of tertiary amines and various organic halides containing chemical bonds such as CCl, NCl, OCl, SCl, and SiCl has been made at 60°C. Some of the binary systems were found to be effective as radical initiator in the polymerization of methyl methacrylate. The relative initiating activities of the halides in the presence of dimethylaniline were found to be in the following order:tert‐C4H9OCl>n‐C4H9NCl2>(n‐C4H9)2NCl ≫ CH3SiCl3⋍ C6H5SiCl3>C6H5SO2Cl>C6H5Cl>C6H5PCl2. Styrene and vinyl acetate polymerized only with the initiator system of dimethylaniline and benzyl chloride. Tri‐n‐butylamine was less active than dimethylaniline. Pyridine and 4‐vinylpyridine, in combination with some organic halides, also initiated the polymerization of methyl methacrylate. TheN‐vinylcarbazole–benzenesulfonyl chloride system, in the presence of methyl methacrylate, gave only the

ISSN:0449-296X    

DOI:10.1002/pol.1970.150080215

出版商:John Wiley&Sons, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe effects of hydrogen on the γ‐radiation‐induced polymerization of ethylene were studied from the viewpoint of polymer structure and kineties. All experiments were carried out at 30°C. In the polymerization of ethylene containing 21.6% hydrogen, the solid polymer was obtained as a main product, while no liquid product was found. There was no difference in hydrogen contents before and after the irradiation; and acetylene, ethane, butane, and butene‐1 were found as gaseous products. The polymer yield increased almost proportionally with dose rate in the presence of 8.0% hydrogen; on the other hand the molecular weight was independent of dose rate. At hydrogen contents of 0–8%, the polymerization rate increased with reaction time and decreased with hydrogen content. The molecular weight also increased with the time, and the extent of the increment decreased with the time and hydrogen content. The number of moles of polymer chain increased proportionally with the reaction time and increased linearly with hydrgen concentration. These results were analyzed by using a graphical evaluation method for kinetics, and the effects of hydrogen on the each elementary step in the polymerization were

ISSN:0449-296X    

DOI:10.1002/pol.1970.150080216

出版商:John Wiley&Sons, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractComplexes of methyl methacrylate and methacrylonitrile with Lewis acids (SnCl4, AlCl3, and BF3) were copolymerized with styrene at −75°C under irradiation with a high‐pressure mercury lamp in toluene solution. The resulting copolymers consisted of equimolar amount of methyl methacrylate or methacrylonitrile and styrene, regardless of the molar ratio of monomers in the feed. NMR spectroscopy showed the copolymers to have an alternate sequence. The tacticities of the copolymers varied with the complex to have an alternate sequence. The tacticities of the copolymers varied with the complex species: the copolymer from the SnCl4complex system had a higher cosyndiotactieity, while those from the AlCl3and the BF3complex systems showed coisotacticity to predominate over cosyndiotacticity. NMR spectroscopic investigation of the copolymerization system indicated the presence of a charge‐transfer complex between the styrene and the methyl methacrylate coordinated to SnCl4. The concentration of the charge‐transfer complex was estimated to be about 30% of monomer pairs at −78°C at a 1:1 molar ratio of feed. The growing end radicals were identified as a methyl methacrylate radical for the AlCl3complex–styrene system and a styrene radical for the SnCl4complex–styrene system by the measurement of the ESR spectra of the copolymerization systems under or after irradation with a high‐pressure mercury lamp. The tacticity of the resulting polymer appears to be controlled by the structure of the charge transfer complex. In the case of the SnCl4complex a certain interaction of SnCl4with the growing end radical seems to be a factor controlling the polymer structure. These copolymerizations can be explained by an alternating charge‐transfer complex copo

ISSN:0449-296X    

DOI:10.1002/pol.1970.150080217

出版商:John Wiley&Sons, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe molecular weight distribution of poly‐N‐vinylcarbazole (PVCar) obtained in solid‐state polymerization with various catalysts or γ‐rays was measured by gel‐permeation chromatography, in order to determine the mechanism of the solid‐state polymerization. In addition, the molecular weight distribution of PVCar obtained in the solution polymerization by the cationic catalyst was also measured. The molecular weight distribution of PVCar obtained in the catalytic solid‐state polymerization was broad and had three peaks, independent of the nature of catalysts, radical and cationic. A large amount of low molecular weight oligomer (probably dimer or trimer) was formed in the catalytic solid‐state polymerization of VCar. The molecular weight distribution of PVCar obtained in the cationic solution polymerization showed only one sharp peak. On the other hand, the molecular weight of PVCar obtained in the radiation‐induced solid‐state polymerization was larger than that obtained in the catalytic solid‐state polymerization, and dimer or trimer was not formed. The molecular weight distribution of PVCar obtained was composed of one sharp peak in the high molecular weight region, and a broad peak in the low molecular weight region, and was extremely different from that of PVCar obtained in the catalytic soli

ISSN:0449-296X    

DOI:10.1002/pol.1970.150080218

出版商:John Wiley&Sons, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractRadiation‐induced postpolymerization of nitroethylene in 2‐methyltetrahydrofuran glass has been studied and discussed in reference to the results obtained from ESR measurements. No postpolymerization occurred at the temperature below −150°C. In the temperature range between −135°C and −78°C, the polymer yield decreased with increasing postpolymerization temperature. The polymer yield increased linearly with the increase of the preirradiation dose in the range below 0.9 × 106r. The mean value for chain initiation was estimated to be about 1.3. The following correlations were observed between the results of the postpolymerization and ESR measurements. The postpolymerization started in the temperature range between −140°C and −135°C, where the ESR spectrum due to the anion radicals of nitroethylene disappeared. The polymer yield of the postpolymerization decreased with the photoirradiation at −196°C before warming the samples in parallel with the photobleachability of the anion radicals observed in the glassy mixture by the ESR method. It was concluded from these results that the radiation‐induced postpolymerization was initiated by the anion radicals of nitroethylene formed by

ISSN:0449-296X    

DOI:10.1002/pol.1970.150080219

出版商:John Wiley&Sons, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe copolymerization of tetraoxane with various olefins by BF3·O(C2H5)2in ethylene dichloride at 30°C has been studied. The gas chromatographic technique was employed for the determination of concentration of each compound. The rate of tetraoxane consumption was decreased by the addition of olefins in the order of; no addition>trans‐stilbene>styrene>1,1‐diphenylethylene>2‐chloroethyl vinyl ether>cyclohexene ≥ indene ≥ α‐methylstyrene. The formation of the methanol‐insoluble copolymer of tetraoxane and olefin was not confirmed. However, 4‐methyl‐4‐phenyl‐1,3‐dioxane and 4,4‐diphenyl‐1,3‐dioxane were formed in the reaction of tetraoxane with α‐methylstyrene and 1,1‐diphenylethylene, respectively. 4,4‐Diphenyl‐1,3‐dioxane was identified on the basis of the molecular weight measurement, elemental analysis and NMR and infrared spectroscopy. On the other hand, 1,3‐dioxane derivatives were not formed in the reaction of tetraoxane with α,β‐disubstituted olefins. Monomer composition dependence of the copolymerization of tetraoxane with 1,1‐diphenylethylene or α‐methylstyrene has been studied. The amount of 4,4‐diphenyl‐1,3‐dioxane formed reached a maximum at a monomer composition of 1:1 in the reaction of tetraoxane with 1,1‐diphenylethylene. The formation o

ISSN:0449-296X    

DOI:10.1002/pol.1970.150080220

出版商:John Wiley&Sons, Inc.    

年代:1970

数据来源: WILEY