Quantitative Epoxidation of High-Vinyl and Dimethylamino-Functionalized Polybutadiene Synthesized via LAP

Abstract

High vinyl polybutadiene (HVPB) liquid rubber has extensive applications in multiple fields, such as rubber, coatings, and adhesives. Quantitative functionalization modification of polybutadiene will further expand its application scope. In this paper, a classic living anionic polymerization (LAP) method was adopted, using 1,2-bis(4-ethylpiperazin-1-yl)ethane (BEPE) as a novel modifier, n-butyllithium as an initiator, and N,N-dimethylvinylbenzylamine as a functional monomer. Through an in situ copolymerization mode, the quantitative and chain-middle/end positioning introduction of tertiary amine functional groups was achieved, and a series of highly vinyl-functionalized polybutadiene (f-HVPB) liquid rubbers with controlled molecular weights and narrow molecular weight distributions were prepared. On the other hand, m-chloroperbenzoic acid was used as an epoxidizing agent to quantitatively epoxidize liquid high-vinyl polybutadiene and functionalized polybutadiene to prepare side-chain highly epoxy/tertiary amine bifunctional polybutadiene (bf-HVPB) products. The effects of different reaction systems, including different solvents, different epoxidizing agent ratios, different temperatures, different molecular weights, and amine modification, on the epoxidation of HVPB and f-HVPB were mainly investigated. The fine structures of the polymerization products were systematically analyzed by 1H NMR, FTIR, DSC, and GPC.