Effect of Diphenyl Ether in Ti-based Ternary Catalyst on Polymerization, Microstructure and Property of cis-1,4-Polyisoprene

A tricomponent catalyst comprising titanium tetrachloride, triisobutyl aluminum and diphenyl ether is developed for the highly cis-1,4-selective polymerization of isoprene. The influence of the content of diphenyl ether and its complexation order on polymerization, microstructure and performance of polyisoprene are studied. The polyisoprene synthesized presents high monomer conversion (91–99%). With the increasing of diphenyl ether content, intrinsic viscosity and viscosity-average molecular weight of polyisoprene increase. The molar percentage of cis-1,4-unit is almost unaffected by diphenyl ether and different complexation sequence. The polyisoprene reveals comparable T_g (–61.31°C) and mechanical strengths (11.14 MPa, 667%) to commercially available LHIR-80 synthesized with neodymium. However, the viscosity and viscosity-average molecular weight of the former are lower than that of the latter, which avails the processability and maintains excellent mechanical properties.