Poly(ethylene glycol) terminated with xanthate (X-PEG-X) was synthesized and used as the reversible addition-fragmentation chain transfer (RAFT) agent for controlling vinyl chloride (VC) solution and suspension polymerizations to synthesize poly(vinyl chloride)-b-poly(ethylene glycol)-b-poly(vinyl chloride) (PVC-b-PEG-b-PVC) triblock copolymers. Results show that the molecular weights (MW) of block copolymers prepared by the solution polymerization are increased with the polymerization conversion

and the molecular weight distribution (MWD) index is lower than 1.65. X-PEG-X is amphiphilic and can effectively reduce the interfacial tension between water and oil. Thus

a novel VC RAFT suspension polymerization method was proposed to prepare PVC-b-PEG-b-PVC copolymers using X-PEG-X as the RAFT agent and a suspending agent. The block copolymer particles have no surface membranes

and MW of copolymer is increased with conversion. However

the block copolymers prepared by suspension polymerization exhibit wider MWD than the block copolymers prepared by solution polymerization

due to the two-phase mechanism of VC suspension polymerization. The chain extension of PVC-b-PEG-b-PVC with vinyl acetate (VAc) further prove the “living” nature of PVC-b-PEG-b-PVC copolymers and result the formation of PVAc-b-PVC-b-PEG-b-PVC-b-PVAc copolymer. PVC-b-PEG-b-PVC copolymers exhibit better hydrophilicity than PVC.