Structure and properties of model polybutadienes -: Effect of microstructure on the dynamic mechanical properties of rubber

A series of controlled microstructure polybutadiene rubbers (PBs) was synthesized via anionic polymerization. Their structure and properties are analyzed by means of GPC, C-13 NMR, DSC, and DAM, and compared to the behavior of some commercial high cis rubbers. Thermal analyses results indicate the presence of crystalline domains of different nature in PBs with high cis-1,4 and high trans-1,4 isomers content, while rubbers with high content of vinyl-1,2 units do not show evidence of crystals. A shift in T, to higher temperatures as vinyl content increases is observed; an expression was found for predicting T-g of rubber from microstructure data.