Synthesis of graft copolymer of syndiotactic poly(styrene-co-4-methylstyrene) with polybutadiene via copolymerization between (styrene and 4-methylstyrene)

Abstract

The basic method for the synthesis of syndiotactic polystyrene-co-polybutadiene graft copolymers was investigated. Firstly, the syndiotactic polystyrene copolymer, poly(styrene-co-4-methylstyrene) (sPSMS), was prepared by the copolymerization between styrene and 4-methylstyrene monomer with Cp [superscript*] TiCl [subscript3]/MMAO at 50 ํC Polymerizations proceeded in argon atmosphere at ambient pressure. Secondly, the copolymer was grafted with polybutadiene (commercialized unsaturated elastomer) by anionic grafting polymerization with a metallation reagent. This graft copolymer showed high melting temperature (240-250 ํC and was different from those of anionic styrene-butadiene copolymers due to the presence of crystalline syndiotactic polystyrene segments. Usually, highly syndiotactic polystyrene has the glass transition temperature at 100 ํC and behaves like glassy polymer (possessed brittle mechanical properties) at room temperature. Thus, thecopolymer might be used as compatibilizer in syndiotactic polystyrene blends for modification of the mechanical properties to compensate the glassy properties of pure syndiotactic polystyrene at room temperature.