Graft copolymers of high vinyl polybutadiene with butadiene-styrene copolymer (SB-grafted HVPBR) were synthesized by polymerization of butadiene in hydrogasoline solution of styrenebutadiene random copolymer (SB) (St% was 30%

Mn was 3.710-3) using a homogeneous MoCl3(OC8H16)2/Al((OPhCH3)(i-Bu)2 catalyst.Graft copolymers were formed when the growing polybutadiene chains threaded through the double bonds of the dissolved SB

giving copolymers with proliferating chain structures.SB was synthesized by anionic polymerization with butyl-lithium as initiator and tetrahydrofuran as structural regulator.The effect of addition amount of SB on the structure and properties of SB-grafted HVPBR was studied by means of FTIR

GPC and GPC-MALLS-Viscometer Analysis System etc.Compared with HVPBR

the molecular weight of SB\|grafted HVPBR and molecular weight distribution and the content of gel raised slightly.The solution dynamic viscosity of HVPBR was decreased to a great extent as a result of the presence of the SB graft chain.The graft efficiency was the highest when the SBs addtion was 3 wt%.Glass transition temperature (Tg) of SB-grafted HVPBR/SBR compounds at varying blending ratios were measured using differential scanning calorimetry (DSC).The results of DSC confirmed that the compatibility of HVPBR and SBR was improved effectively by grafting SB onto HVPBR.