科研之友
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摘要
Well-defined polystyrene and its functional derivatives, poly(vinylbenzyl chloride) (PVBC), poly(N,N-diethyl vinylbenzylamine) (PDEVBA), and poly(vinylbenzyl alcohol) (PVBA) were synthesized via (S)-1 -dodecyl-(S')-(alpha,alpha'-dimethyl-(alpha ''-acetic acid) trithiocarbonate-inediated ambient-temperature reversible addition - fragmentation chain transfer radical (RAFT) polymerization of the corresponding styrenic-based monomers under mild long-wave radiation, using a (2.4.6-trimethylbenzoyl) diphenylphosphine oxide photoinitiator. The effect of chloromethyl, hydroxymethyl, and tert-amino functionalities on reactivity and controlled behavior of ambient-temperature RAFT polymerization of styrenic-based monomers under mild conditions was studied in this paper. The results indicated that the photolysis of trithiocarbonate groups and the irreversible termination reactions of their intermediate radicals were significantly suppressed for the duration of the RAFT polymerization under mild long-wave radiation, thus keeping the characteristic living behavior. Kinetic studies confirmed the well-controlled behavior of these RAFT polymerizations. Moreover, the chloromethyl, tert-amino, or hydroxymethyl functionalities significantly improved reactivity of styrenic-based monomers, thus remarkably accelerating the process of ambient-temperature RAFT polymerization. Although RAFT polymerization of DEVBA and VBC monomers proceeded at a comparable rate, the initialization period in RAFT polymerization of DEVBA monomer was clearly longer than that of the VBC monomer. VBA was the most reactive monomer among these styrenic-based monomers. Ambient-temperature RAFT polymerization of VBA under mild long-wave radiation was well controlled up to 31% monomer conversion in 1.5 h. The living behavior of these arnbient-temperature RAFT polymerizations facilitated the direct synthesis of well-defined all-styrenic-based block copolymers under mild conditions.
- 出版日期2007-12-25
- 单位湘潭大学
