两亲性苯乙烯嵌段共聚物的合成及结构表征

Synthesis and Characterization of Styrene Amphiphilic Block Copolymer

摘要:

以(α,α′-二甲基-α-乙酸)-三硫代碳酸酯(BDATC)为链转移剂，采用可逆-加成-断裂链转移(RAFT)自由基聚合方法合成了末端带有-COOH官能团的两亲性嵌段共聚物聚苯乙烯-b-聚甲基丙烯酸聚乙二醇单甲醚-b-聚苯乙烯(PSt-b-POEOMA-PSt),这种含有亲水性端基的嵌段共聚物可以自组装成核-壳结构的纳米微粒，用以载药高分子的模板研究。利用FTIR、1H-NMR、GPC对产物结构进行表征，用热失重(TG)和差示扫描量热(DSC)的方法研究了三种不同比例的嵌段共聚物的热性能。实验结果表明，通过RAFT聚合方法得到了所设计的嵌段共聚物，分子量分布1.35左右；嵌段共聚物的热稳定性较好，通过玻璃化转变温度(Tg)的变化推测出嵌段共聚物中两种嵌段比例对两嵌段相容性的影响。

Abstract:

The block copolymer of PSt-b-POEOMA-b-PSt with the end of -COOH functional group has been synthesized by reversible addition fragmentation chain-transfer (RAFT) using S,S′-Bis(α,α′-dimethyl-α-acetic acid)-trithiocarbonate (BDATC) as the chain transfer agent. The block copolymer containing hydrophilic end groups can be assembled into the core-shell nanoparticles for drug-loaded polymer template. The architecture of the copolymer was confirmed by FTIR, 1H NMR spectra and GPC. Furthermore, through the thermogravimetric (TG) and differential scanning calorimetry calorimeter (DSC) methods, the thermal properties of the three different proportions of block copolymers were studied. Results showed that RAFT polymerization was successful to synthesize the designed block copolymer; the molecular weight distribution of the controlled block copolymer was about 1.35. And the block copolymers had good thermal stability; the compatibility of the two components could be speculated by the change of the glass transition temperature (Tg).