烯烃嵌段共聚物分子链结构非均匀性的研究

Chain Heterogeneity of Olefin Block Copolymer

利用交叉分级色谱(TREF-GPC联用)和连续自成核退火热分级(SSA)技术研究了烯烃嵌段共聚物(OBC)链结构的非均匀性。结果表明,样品1的级份主要集中在85℃高温区域,且相对分子质量分布较窄;相对分子质量较低的样品2和3的支链分布更宽,朝低温区域移动;共聚单体在OBC树脂内分布具有统计上的非随机性。SSA研究发现,3种OBC样品均具有多重熔融峰,反映了分子链内的非均匀性。

Molecular chain heterogeneity of olefin block copolymers(OBC)was investigated using Cross Fractionation Chromatography(TREF-GPC)and successive self-nucleation annealing(SSA)thermal fractionation technique.The dominant fraction of OBC-1 was eluted in the high temperature region at 85℃,and the relative molecular weight distribution was narrower.The distribution of chain branches of OBC-2 and OBC-3 with lower relative molecular weight were broader and moved toward the low temperature region.In terms of the distribution of comonomer in OBC,it can be concluded that the comonomer distribution was statistically non-random.After SSA treatment,the appearance of multiple melting behaviors for each sample indicated that a heterogeneous intermolecular distribution existed in the chains of OBC resin.