温敏二嵌段胶束种子大分子RAFT试剂调介下的种子分散RAFT聚合

项目名称： 温敏二嵌段胶束种子大分子RAFT试剂调介下的种子分散RAFT聚合

项目编号： No.21474054

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 张望清

作者单位： 南开大学

项目金额： 88万元

中文摘要： 大分子RAFT（macro-RAFT）试剂调介下的分散RAFT聚合是制备浓度高、稳定性好的嵌段共聚物胶体的有效方法。为了消除或降低分散RAFT聚合迟滞时间、揭示嵌段共聚物胶体的生长机制，本项目用温敏二嵌段共聚物胶束作为种子macro-RAFT试剂，调介苯乙烯等单体的种子分散RAFT聚合。温敏二嵌段共聚物胶束种子macro-RAFT试剂的使用，既避免了制备常规种子macro-RAFT试剂的复杂过程，又能方便地调节胶束种子macro-RAFT试剂的尺寸/形态，还有利于减少分散RAFT聚合迟滞时间。通过研究RAFT端基的Z-基团在胶束种子macro-RAFT试剂中的位置、胶束种子macro-RAFT试剂的大小和形态等因素对聚合动力学、三嵌段共聚物分子量及其分布、三嵌段共聚物胶体形态结构的影响，揭示嵌段共聚物分子链增长机理和胶体生长规律，探索出一条制备浓度高、结构可控的三嵌段共聚物胶体的有效方法。

中文关键词： RAFT聚合；温敏聚合物；嵌段共聚物；种子聚合；分散聚合

英文摘要： The macro-RAFT agent mediated dispersion polymerization is a valid strategy to prepare concentrated block copolymer nano-objects uniformly dispersed in solvent. In a general macro-RAFT agent mediated dispersion polymerization especially at the case of inactive monomers such as styrene, a long induction-time due to the initial slow homogeneous polymerization is usually involved, which prolongs the polymerization or makes the polymerization out of the control in polymer molecular weight and its distribution. In this subject, thermo-responsive diblock copolymer micelles containing the RAFT terminal instead of a soluble macro-RAFT agent are employed to eliminate/decrease the induction-time to accelerate the dispersion RAFT polymerization. The application of the thermo-responsive micellar macro-RAFT agent in dispersion RAFT polymerization has three advantages including (1) the convenient preparation of the micellar macro-RAFT agent just by increasing the temperature above the lower critical solution temperature (LCST) of the thermo-responsive diblock copolymer, (2) the easily tunable size and even the morphology the micellar macro-RAFT agent by changing the chemical composition of the thermo-responsive diblock copolymer, and (3) the accelerated RAFT polymerization with no or shortened induction-time. By exploring the structure of the micellar macro-RAFT agent including the site of the Z-group in the RAFT terminal in the micellar macro-RAFT agent, the size and morphology of the micellar macro-RAFT agent affecting on the seeded dispersion RAFT polymerization, the polymerization kinetics, the evolution of the triblock copolymer molecular weight and its distribution with the monomer conversion, and the growth of the ABC triblock copolymer nano-objects during the seeded dispersion RAFT polymerization are clarified, and a valid stategy to prepapre concentrated, well-defined ABC triblock copolymer nano-objects is proposed.

英文关键词： RAFT polymerization;thermo-responsive polymers;block copolymers;seeded polymerization;dispersion polymerization