摘要:

Poly(dichlorobutane sulfide) I and poly(dichlorobutane disulfide) II have been prepared in 97% yield by addition copolymerization of butadiene with sulfur dichloride and sulfur monochloride, respectively. The polymers were characterized by elemental analysis, infrared spectrum, inherent viscosity, and thermogravimetric analysis. The reactions of several dienes with sulfur dichloride (but not with sulfur monochloride) have been reported in the literature. All were reported to give mainly the intramolecular addition products. However, it has very recently been found that diolefins with double bonds rigidly separated from each other, or with double bonds so situated that intramolecular reaction is thermodynamically unfavorable, preferentially undergo polymerization with sulfur monochloride or sulfur dichloride. In the case of butadiene, polymerization is thermodynamically more feasible than intramolecular addition due to the dipole repulsion and eclipsing chain which would be present in the intramolecular reaction products.

ISSN:0022-233X    

DOI:10.1080/10601326908053802

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A study of the polymerization of some vinyl monomers by the system of N-bromosuccinimide (NBS) and reduced nickel was made at 60°C. It was found that this system shows excellent activity for methyl methacrylate, weak activity for styrene, and no effect for vinyl acetate polymerizations. From the results of the polymerization kinetics, the copolymerization experiment, and the effect of radical inhibitors, it was proved that polymerization by this initiator system proceeds via a radical intermediate. The initiation is considered to be induced by a succinimide radical that is produced. The mechanism for initiation is presented and discussed.

ISSN:0022-233X    

DOI:10.1080/10601326908053803

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The radical decompositions of eight kinds of alkyl α, α′-azobisiso-butyrates in various solvents, such as cyclohexane, benzene, acetoni-trile, methanol, and acetic acid, and in methanol solution of stannic chloride or zinc chloride were investigated. It was found that the methyl α, α′-azobisisobutyrate decomposed through first-order kinetics in these solvents, but the resulting rate constants changed significantly with the kind of solvent or metal chloride used. These rate constants were also observed to correlate with the polarities and the proton-donating abilities (ETvalues) of the solvents used. The activation enthalpies and entropies at 60°C were determined; the former values were kept constant independent of the reaction medium, but the latter values were changed.

ISSN:0022-233X    

DOI:10.1080/10601326908053804

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A study of the copolymerization of methyl methacrylate and styrene in monosubstituted benzenes such as benzene, benzonitrile, benzyl alcohol, and phenol was made at 60°C. It was found that the copolymerization parameters changed significantly with the polarity of solvents, and the relative reactivity of methyl methacrylate toward the polystyryl radical was correlated with the ETvalues of solvents. These results and spectroscopic data suggest that in the transition state of this copolymerization the polarized structureof methyl methacrylate monomer became important, enhancing its reactivity, as the solvents became more protic.

ISSN:0022-233X    

DOI:10.1080/10601326908053805

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The reactions of n-Bu2Zn and n-Bu3Al with α,β-unsaturated ketones were studied. The elementary reactions were found to be conjugate addition and hydrogen abstraction reactions. One n-butyl group of metal alkyl was consumed in the conjugate addition, in contrast to the hydrogen abstraction reaction, all n-butyl groups being consumed in the latter elementary reaction. Conjugate addition rate constants were calculated regarding the conjugate addition as a second-order reaction with metal alkyl. On the basis of the kinetic data, infrared spectra of the reaction system, and the relative reactivity of the homologous vinyl ketones (α-methyl-substituted > unsubstituted > β-methyl-substituted), a four-centred mechanism was presented for the conjugate addition reaction of the metal alkyl with α, β-unsaturated ketone.

ISSN:0022-233X    

DOI:10.1080/10601326908053806

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

1, 3-Cyclohexadiene was polymerized at 0°C in methylene chloride or benzene using boron trifluoride etherate or stannic chloride-trichloroacetic acid as catalyst. The former catalyst led to a stationary-state polymerization but the latter brought about a non-stationary-state polymerization in which the initiation reaction was very fast. The very fast initiation reaction is a consequence of a strong interaction between the monomer and the metal halide. Part of the added catalysts was made inactive by the interaction with the excess monomers.

ISSN:0022-233X    

DOI:10.1080/10601326908053807

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Cis, cis-1, 3-cycloöctadiene was polymerized by titanium tetra-chloride-trichloroacetic acid in methylene chloride or toluene at -78°C. The polymerization was very fast at first but slowed down toward the end. When the polymerization was conducted in methylene chloride, it stopped completely after the fast polymerization ceased, and a portion of monomers was left unreacted. On the other hand, when toluene was used as a solvent, a slow polymerization was observed after the fast polymerization finished, and the polymerization went to completion. The conversion reached during the fast polymerization was lower as the initial monomer concentration was higher. These experimental findings were interpreted in terms of a strong interaction between the excess monomers and the catalyst to form an inactive monomer-metal halide adduct, which has been commonly observed with other cyclic dienes studied so far, such as cyclopentadiene and 1, 3-cyclohexadiene. To explain the effect of solvent, a reactivation of the initially formed monomer-metal halide adduct was invoked in the case of toluene as solvent, which has not been observed with other cyclic dienes.

ISSN:0022-233X    

DOI:10.1080/10601326908053808

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The structure and properties of poly(1, 3-cyclohexadiene) and poly(cis, cie-1, 3-cycloöctadiene) obtained in the cationic polymerization were investigated.

ISSN:0022-233X    

DOI:10.1080/10601326908053809

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The rate of polymerization of a diepoxide and a dicarboxylic acid anhydride with a tertiary amine catalyst has been explored. Molar ratios of epoxy to anhydride in the range from 10: 1–0. 8:1 were investigated in a temperature range of 60–120°C. The observed reaction rate may be expressed by the following rate equation:

ISSN:0022-233X    

DOI:10.1080/10601326908053810

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A combination of dynamic mechanical and swelling properties has been used to elucidate the structure of epoxy resin systems as a function of time and temperature of cure, concentration of flexibilizer, and curing agent concentration. The dynamic properties of the resin in the rubbery region were used to determine the molecular weights between cross-links. The poor network structure formed with epoxies is shown by the dynamic and swelling tests. The existence of heterogeneity or two phases has been found in the epoxy resin system under certain polymerization conditions. Broad damping peaks may not be due to chemical heterogeneity but may be the result of the curing reaction continuing during the tests.

ISSN:0022-233X    

DOI:10.1080/10601326908053811

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor