P2VP-b-PS-b-PI三嵌段共聚物的RAFT合成及表征

以S-十二烷基-S’-(α,α’-二甲基-α’’-乙酸)-三硫代碳酸酯(DDMAT)为链转移剂,通过可逆加成-断裂链转移自由基聚合(RAFT)方法制备了窄分布的聚2-乙烯基吡啶。再以该聚合物为大分子链转移剂,引发苯乙烯的RAFT聚合,得到聚2-乙烯基吡啶-b-聚苯乙烯(P2VP-b-PS)的两嵌段共聚物。以P2VP-b-PS为RAFT试剂,合成聚2-乙烯基吡啶-b-聚苯乙烯-b-聚异戊二烯(P2VP-b-PS-b-PI)的三嵌段共聚物。运用1H NMR、IR和凝胶渗透色谱(GPC)等技术对产物的结构和分子量及分子量分布进行表征,采用原子力显微镜(AFM)观察三嵌段共聚物薄膜的微相分离结构。结果表明,所得三嵌段共聚物P2VP72-b-PS136-b-PI300分子量分布较窄(PDI=1.69),合成过程具有活性/可控聚合特征,聚合物薄膜经溶剂退火处理后出现了明显的微观相分离结构。

rAft-Based synthesis and characteriZation of P2 VP-b-Ps-b-PI triblock polymers

Macro-RAFT agent,poly（2-vinyl pyridine）were synthesized by reversible addition-fragmenta-tion chain transfer（ RAFT）polymerization using S-dodecyl-S’-（α,α’-dimethyl-α’’-acetic acid）-tri-thiocarbonate as the chain transfer agent. Poly（2-vinyl pyridine）-b-poly（ styrene）（ P2VP-b-PS）diblock copolymers were synthesized using styrene as monomer and the macro-RAFT agent as the chain transfer a-gent. Then,poly（2-vinyl pyridine）-b-poly（styrene）-b-poly（isoprene）（P2VP-b-PS-b-PI）triblock copol-ymers were synthesized using isoprene as monomer and the P2VP-b-PS as the chain transfer agent. The molecular structure and molecular weight of the products were characterized by 1 H NMR,IR and GPC. The results indicate that RAFT is a successful access to the triblock copolymer P2 VP76-b-PS160-b-PI300 with narrow molecular weight distribution（PDI=1. 69）. The film from P2VP72-b-PS136-b-PI300,character-ized by AFM,has an obvious microphase structure after solvent annealing.