Synthesis and Characterization of Crystalline Styrene-b-(Ethylene-co-Butylene)-b-Styrene Triblock Copolymers

作者:Lin, F;Wu, CJ;Cui, DM
关键字:coordination polymerization, crystalline SEBS triblock copolymers,high temperature thermoplastic elastomer,rare-earth metal complexes,syndiotactic polystyrene


By merit of dual catalysis of the cationic rare-earth complex [(η5-Flu-CH2-Py)Ho(CH2SiMe3)2(THF) (Flu?=?fluorenyl, Py?=?pyridyl) for the living polymerizations of butadiene (BD) and styrene (St), the crystalline styrene-butadiene-styrene (SBS) triblock copolymers consisting of elastic polybutadiene (PBD) sequences with suitable 1,4 regularity (about 70%) and crystalline syndiotactic polystyrene (sPS, [rrrr]?>?99%) sequences were successfully synthesized through sequential addition of St, BD, and St monomers. The catalytic system showed high polymerization activities for St and BD in a controlled manner. The crystalline styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) triblock copolymers were obtained by hydrogenation of the above SBS copolymers. The observation of a strong endothermic peak at 266 °C in their differential scanning calorimetry (DSC) curves confirmed the existence of the sPS blocks in the crystalline SEBS different from the industrial product Kraton SEBS-1652. Thermal degradation temperature of the crystalline SEBS (418?±?2 °C) indicated the well thermostability and process window of this polymer.