Homologous Poly(isobutylene)s: Poly(isobutylene)/High-Density Poly(ethylene) Hybrid Polymers

Abstract

We report on the synthesis of poly(homo-isobutylene) and poly(homo-α-methylstyrene) and the thermal properties of these new polymers. Based on the ring-opening metathesis polymerization (ROMP) of 3,3-dimethylcyclopropene and 3-methyl-3-phenyl-cyclopropene, the respective ring-opened polymers were generated. Several catalytic systems (first-generation (I), second-generation (II), third-generation Grubbs-type (IV) and the Schrock-type initiator Mo(N-2,6-iPr2C6H3)(CHCMe2Ph)(OCMe3)2 (III) were used. Particularly II, III and IV offered access to living polymerization reactions in the case of 3-methyl-3-phenyl-cyclopropene, however, not with 3,3-dimethylcyclopropene. The obtained ROMP-polymers were hydrogenated using tosylhydrazide, furnishing poly(homo-isobutylene) and poly(homo-α-methylstyrene) in high yields. Thermal-measurements (DSC-measurements) revealed Tg- and Tm-values located between those of poly(isobutylene), poly(styrene), and high-density poly(ethylene).