Facile access to carboxyl-terminated polybutadiene and polyethylene from cis-polybutadiene rubber

Carboxyl-terminated polybutadiene (CTPB) is a widely used telechelic liquid rubber, which is mainly prepared by anionic or free-radical polymerization of 1,3-butadiene. It is known that the microstructure of liquid polybutadiene rubber largely affects its processability and mechanical properties. However, it is hard to control its microstructure in the free radical or anionic polymerization. In this study, a series of CTPB with high cis-1,4 content has been prepared for the first time via the oxidolysis and selective oxidation of cis-polybutadiene rubber (BR). Hydrogenation of their C(sic)C double bonds with p-toluenesulfonyl hydrazide/tri-n-propylamine (TSH/TPA) reagents afforded carboxyl-terminated polyethylenes (CTPE). For comparison, commercial CTPB (FCTPB), prepared by free-radical polymerization of 1,3-butadiene, was also hydrogenated and gave FCTPE with more ethyl branches. Linear CTPE (L-CTPE) was synthesized by ring-opening metathesis polymerization of 1,5-cyclooctadiene in the presence of maleic acid and subsequent hydrogenation. The microstructure of the polymers was established by FT-IR, H-1 NMR, C-13 NMR, and GPC and their thermal properties were determined by DSC and TGA. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46934.