PSt-b-PAA的ATRP法合成及其在甲苯中自组装

Synthesis of PSt-b-PAA by ATRP Approach and Its Self-Assembling Behavior in Toluene

以α-溴乙苯为引发剂,溴化亚铜为催化剂,2,2′-联吡啶为配体,二甲苯为溶剂,采用开放的溶液聚合体系,在磁力搅拌与氮气保护下,用原子转移自由基聚合ATRP(A tom T ransfer R ad ica lPo lym erization)法合成了嵌段共聚物聚苯乙烯-b-聚丙烯酸丁酯(PS t-b-PBA);用FT IR,1H-NM R,GPC等手段对活性聚合进行了确认,对嵌段共聚物进行了表征;水解PS t-b-PBA制备了两亲性嵌段共聚物苯乙烯-b-聚丙烯酸(PS t-b-PAA);采用直接溶解法配制了PS t-b-PAA在甲苯中的反胶束溶液;利用透射电镜(TEM)观察有效地考察了两亲嵌段共聚物PS t-b-PAA在甲苯溶液中的自组装行为.研究结果表明,在开放体系下也能较好地实施原子转移自由基聚合,制得窄分布的嵌段共聚物;控制两嵌段的长度可制得亲水链PAA短的两亲嵌段共聚物PS t-b-PAA,使其在甲苯中发生自组装,形成以亲水段为核,疏水段为壳的反胶束结构.

The block copolymer of PSt-b-PBA with a low polydispersity has been synthesized by atom transfer radical polymerization （ATRP） in open solution polymerization system using 1-phenylethyl bromide （1-PEBr） as initiator, cuprous bromide as catalyst, 2,2＇-bipyridine （bpy） as ligand and xylene as solvent. The polymerization is conducted using an electromagnetism agitator under the protection of nitrogen atmosphere. After the characterization of the block copolymer PSt-b-PBA and the validation of the living polymerization by GPC, FTIR, and ^1H-NMR, amphiphilic block copolymer of PSt-b-PAA has been prepared by hydrolyzing of PSt-b-PBA. The reversed micellization solution of PSt-b-PAA in toluene has been prepared by directly dissolving method, and investigated by TEM observation mean. Research results show that the ATRP polymerization can also be realized well in open system, and amphiphilic block copolymer of PSt-b-PAA with shorter PAA segment and a low polydispersity can be obtained by controlling polymerization time. The reversed micells with hydrophilic core and hydrophobic shell can be formed by spontaneously self-assembling of PSt-b-PAA in toluene.