双亲性嵌段共聚物的RAFT合成及其胶束化行为研究

RAFT-basen Synthesis and Micellization of Amphiphilic Block Copolymers

以二硫化二异丙基黄原酸酯(DIP)为链转移剂,AIBN为引发剂,通过可逆加成-断裂链转移(RAFT)自由基聚合的方法制备得到大分子链转移剂聚醋酸乙烯酯(PVAc)。进而引发第二单体N-乙烯基乙酰胺(NVA)进行RAFT反应制备得到不同嵌段比的双亲性嵌段共聚物PVAc-bPNVA。红外光谱(FT-IR)、核磁共振氢谱(1 H NMR)和凝胶渗透色谱(GPC)分析表明,所得聚合物结构明确,且分子量分布较窄,符合活性聚合特征。进而使PVAc-b-PNVA在选择性溶剂(DMF/H2O)中自组装形成胶束,研究了不同初始浓度和链段比对胶束粒径和形态的影响。

Macromolecular chain transfer agent, polyvinyl acetate （PVAc）, was prepared by reversible ad dition fragmentation chain transfer （RAFT） radical polymerization with dithiodiisopropyl xanthate （DIP） as chain transfer agent and AIBN as initiator. The amphiphilic block copolymer PVAc b PNVA with dif ferent segment ratio was prepared by RAFT using PVAc as macromolecular chain transfer agent. The characterization results showed the polymers with accurate structure by fourier transform infrared （FT IR） and nuclear magnetic resonance （1H NMR）, with narrow polydispersity （Mw/Mn） by gel permeation chro matography （GPC） which accords with the characteristics of active polymerization. The amphiphilic block copolymers PVAc b PNVA in selective solution （DMF/H2O） could self assemble to form micelles. The effects of different initial concentration and chain ratio on the micelle size and morphology were studied.