Kentaro Mashita

Alternating copolymers of isobutylene and acrylic ester by complexed copolymerization

Abstract Alternating copolymers of isobutylene and acrylic ester (designated as ‘AIM’ copolymers) were synthesized by complexed copolymerization in the presence of alkylboron halide. Various characteristic properties of the AIM copolymers were revealed. AIM copolymers showed singular properties which could not be expected from those of the corresponding homopolymers. The glass transition temperature, thermal decomposition temperature and tensile strength of AIM copolymers were greater than those of both homopolymers, i.e. additivity was not established. The solubility parameter and refractive index of AIM copolymers showed slightly smaller values than the additive ones of both homopolymers. The hydrolysis resistance of AIM copolymers was excellent compared with that of the corresponding poly(acrylic ester)s.

Alternating copolymerization of isobutylene and acrylic ester with alkylboron halide

Abstract It was found that alkylboron halide, such as ethylboron dichloride and diethylboron chloride, was a highly active catalyst for the alternating copolymerization of isobutylene and acrylic ester. The alternating sequential structure of the resulting copolymers was proved by analysis of n.m.r. spectra. The Lewis acidity of the catalyst, the molar ratio of catalyst to acrylic ester and the molar ratio of isobutylene to acrylic ester played important roles in determining the regularity of the alternating sequence. Copolymer molecular weight had an intimate correlation with the Lewis acidity of the catalyst. The polymerization rate was maximum at about −50°C and decreased rapidly above 0°C. The present copolymerization proceeded via a complexed radical mechanism. The cocatalytic effect of oxygen was remarkable and the molecular weight controlling effect of mercaptan was notable. Alkylboron halide has various advantage compared with alkylaluminium halide.

Functional copolymers of isobutylene and acrylic ester

Reactive copolymers of isobutylene and acrylic ester were successfully synthesized by the incorporation of acryloyl chloride or maleic anhydride into alternating copolymers of isobutylene and acrylic ester by means of complexed copolymerization catalysed with alkylboron halide. The terpolymers of isobutylene, acrylic ester and acryloyl chloride (AILM) and isobutylene, acrylic ester and maleic anhydride (AIHM) reacted with many compounds. Via the polymer reactions based on AILM and AIHM, various functional copolymers of isobutylene and acrylic ester were synthesized, which contained carboxyl group, amide group, hydroxyl group, nitrile group, epoxy group and so forth on the pendant of the polymer chains.

Curable copolymers of isobutylene and acrylic ester

Abstract Curable copolymers of isobutylene and acrylic ester were successfully synthesized by incorporation of a third monomer into alternating copolymers of isobutylene and acrylic ester by means of complexed copolymerization catalysed with alkylboron halide. As the third monomer, acrylic ester including an unsaturated bond in the ester group (AEU), such as crotyl acrylate, or vinyl monomer including a chlorine atom (CVM), such as 2-chloroethyl vinyl ether, was effectively incorporated. The terpolymers containing AEU (AIDM) were easily vulcanized with sulfur. The terpolymers containing CVM (AICM) were sufficiently well cured with polyamine. The cured products of both AIDM and AICM had excellent properties in terms of oil resistance, water resistance and others. The blend of AIDM and ethylenepropylenediene rubber was satisfactorily co-vulcanized with sulfur.