The synthesis of well-defined poly(styrene-b-isobutylene-b-styrene) (SIBS) triblock copolymers was accomplished by cationic sequential block copolymerization of isobutylene (IB) with styrene (St) using 1,4-di(2-chloro-2-propyl)benzene (DCC)/TiCl4 /2,6-di-tert-butylpyridine(DtBP) as an initiating system in methyl chloride (CH3Cl)/methylcyclohexane(MeChx) (50/50 v/v) solvent mixture at -80 ℃. The triblock copolymers exhibited excellent thermoplastic and elastomeric characteristics. Tensile strengths and Shore hardness increased with increasing polystyrene (PS) content, while elongation at break decreased. The blood-compatibility of SIBS was assessed by SEM observation of the platelet adhesion, blood clotting time and haemolysis ratio. The haemolysis ratios were below 5% which met the medical materials standard. The platelet adhesion test further indicated that SIBS block copolymers had a good blood compatibility.

Keywords: poly(styrene-b-isobutylene-b-styrene); haemocompatibility; thermoplastic elastomer; living/controlled cationic polymerization