关键词 :RAFT共聚合;链转移常数;分子量;分子量分布
Chain Transfer Constant Determination in RAFT Copolymerization
Abstract :The objective of this work mainly focused on the relationship between molecular weight and molecular weight distribution with various monomer compositions in the reversible addition-fragmentation chain transfer (RAFT) polymerization. The chain transfer constant with various monomer compositions were experimentally determined for the copolymerization systems of MMA/BA mediated by RAFT with Z=-CH2C6H5 at 60℃. The results showed that the RAFT agent’s control capacity to monomer is closely related to the chain transfer constant. In the copolymerization of MMA and BA, Ctr decreases monotonously with the increase of fMMA, therefore we can prepare polymers with much narrower molecular weight distribution with the decrease of fMMA. The relative addition and fragmentation probability in the copolymerization of MMA and BA with Z=-CH2C6H5 indicated that in the synthesis of the block copolymer of MMA and BA, the block of PMMA should be synthesized firstly in order to gain a fast block transition.