用氮锂引发剂合成端基官能化苯乙烯-丁二烯-苯乙烯三嵌段共聚物

Synthesis of end group functionalized styrene-butadiene-styrene three block copolymer using lithumamide as initiator

研究了六亚甲基亚胺基锂、氮锂和正丁基锂引发剂引发苯乙烯的聚合速率,合成了端基官能化苯乙烯-丁二烯-苯乙烯三嵌段聚合物(SBS).结果表明,在设计相对分子质量相同的情况下,随着四氢呋喃加入量的增加,端基官能化SBS的1,2-结构质量分数增加,顺式-1,4-结构和反式-1,4-结构质量分数下降,但两者比值基本不变.相同条件下,用氮锂引发剂制备的端基官能化SBS的1,2-结构质量分数要略高于用正丁基锂引发剂制备的SBS.

A modified polymer having end-functional groups capable of interacting with other polar materials has recently attracted many interests. The styrene-butadiene-styrene three block copolymer（SBS） were synthesized with anionic polymerization using lithium hexamethyeneimine （ LHMI ） as functionalized initiator. Rate of polymerization of styrene with different kinds of initiators in the first block were studied by establishing relationship between conversion and time, as plotted in Fig 1. Because the rate of propagation of the polymerization of styrene initiated with LHMI was very slow compared to n-butyllithium, five times amount of butadiene was attached to LHMI forming new N - Li initiator . The resulted N - Li initiator can initiate styrene quickly compared to LHMI. So end functionaiized SBS was prepared using N - Li as initiator, tetrahydrofuran（THF） as polar modifier.