醇相光引发RAFT分散聚合制备全丙烯酸酯二嵌段共聚物纳米材料

Preparation of All-acrylic Diblock Copolymer Nano-objects via Alcoholic Photoinitiated RAFT Dispersion Polymerization

在40℃反应条件下,以聚丙烯酸羟乙酯(PHEA)为大分子RAFT试剂,丙烯酸异冰片酯(IBOA)为聚合单体,在乙醇/水混合溶剂中,通过光引发RAFT分散聚合制备全丙烯酸酯(PHEA_(25)-PIBOA_n)嵌段共聚物纳米材料.反应在可见光(λ_(max)=405 nm,0.4 mW/cm^2)照射下,30 min内达到很高的单体转化率(95%).聚合反应动力学结果表明反应主要分为两个阶段,凝胶渗透色谱结果表明聚合过程体现出良好的可控性.探究了嵌段共聚物纳米材料的形貌变化,成功得到了球形和囊泡结构形貌.

All-acrylic poly(2-hydroxyethyl acrylate)-poly(isobornyl acrylate)(PHEA25-PIBOAn)block copolymer nano-objects were prepared by photoinitiated RAFT dispersion polymerization of IBOA in ethanol/water at 40°C using a PHEA macromolecular chain transfer agent(macro-CTA).Polymerizations proceeded rapidly upon exposure to visible light irradiation(λmax=405 nm,0.4 mW/cm2)with high monomer conversion(95%)being achieved within 30 min.The kinetics of polymerization indicated that the polymerization could be separated into two stages.Gel permeation chromatography(GPC)analysis demonstrated that good control was maintained throughout the photo-PISA process,and the final block copolymers exhibited relatively low polydispersities(Mw/Mn 1.50).Spherical micelles and vesicles were prepared by this method.