Batch-semi-batch two-stage RAFT mini-emulsion polymerization of styrene
A batch-semi-batch two-stage reversible addition-fragmentation chain transfer(RAFT)mini-emulsion polymerization of styrene was investigated.It was found that the starting point of the feeding stage(the semi-batch stage)and the solid content of the final latex were critical to reducing the amount of coagulum.The monomer feeding of the second stage should start after monomer conversion 40% of the first stage and the solid content of the final latex should remain below 40%.Under such conditions little coagulum was observed.It was concluded that the two-stage semi-batch RAFT mini-emulsion polymerization was effective to synthesize higher molecular weight polymer(～8×104 g·mol-1)with narrow molecular weight distribution(PDI=～1.3)and low residues of the surfactant and co-stabilizer(～1.5%,mass).