原子转移自由基聚合法合成双亲性两嵌段大分子单体

Synthesis of Amphiphilic Block Macromonomer by Atom Transfer Radical Polymerization

以对氯甲基苯乙烯(CMSt)为功能性引发剂引发苯乙烯在甲苯溶液中进行原子转移自由基聚合(ATRP)反应,得到端基中含有不饱和双键和卤素原子的聚苯乙烯(PSt—Cl)大分子引发剂;该反应具有活性聚合的特征,所得PSt—Cl的实测相对分子质量大于理论相对分子质量,说明CMSt的引发效率不高,但通过调节聚合反应条件可有效控制PSt—Cl的相对分子质量。以PSt—Cl大分子为引发剂引发N-异丙基丙烯酰胺(NIPAAm)进行ATRP反应,合成了双亲性两嵌段PSt-b-PNIPAAm大分子单体。用傅里叶变换红外光谱和核磁共振对PSt-b-PNIPAAm的结构进行表征,结果显示,PSt-b-PNIPAAm为目标产物。用具有不同相对分子质量的PSt-b-PNIPAAm大分子单体在甲苯溶剂中进行均聚反应,实验结果证明,PSt-b-PNIPAAm端基中的双键具有良好的聚合反应活性。

Atom transfer radical polymerization （ATRP） of styrene was studied using p-chloromethylstyrene （CMSt）as functional initiator in toluene solution. CMSt exhibited low initiating efficiency. The resulted polystyrene with a chloro-terminal in macromonomer chain PSt-Cl （PSt： polystyrene） possesses higher relative molecular mass than expected. However,relative molecular mass of PSt-Cl can be controlled by adjusting polymerization conditions. A novel amphiphilic block PSt-b-PNIPAAm macromonomer was synthesized by using the obtained PSt-Cl as macromolecule initiator, which initiates ATRP of N-isopropylacrylamide （NIPAAm）. Structure and relative molecular mass of synthesized PSt-b-PNIPAAm were characterized by means of FTIR and 1^H NMR. Homopolymerization of PSt-b-PNIPAAm with different relative molecular mass was carded out in toluene to verify the polimerization activity of terminal C = C bond in PSt-b-PNIPAAm molecule.