基于聚乙烯的无规和嵌段接枝共聚物的制备

发布时间：2018-10-04 20:11

【摘要】：采用乙烯配位聚合和巯基-烯点击化学相结合的方法制备了羟基封端的线性聚乙烯,末端羟基含量接近100%;利用酰氯与羟基的高效反应,将羟基封端的聚乙烯转化为降冰片烯封端的聚乙烯大单体(PE-NB).使用Grubbs II代催化剂,将大分子单体与降冰片烯(NB)单体进行开环易位共聚,通过调整单体的投料比和加料方式制备了分子量和组成可控的聚降冰片烯-g-聚乙烯(PNB-g-PE)接枝共聚物.其中,无规共聚时,大单体的转化率接近100%,所得无规接枝共聚物的重均分子量为1.79×10~4~3.14×10~4,分子量分布指数为2.09~2.60,聚乙烯链段的质量分数为4.6%~16.8%;而嵌段共聚时,由于空间位阻原因,大单体的转化率约为80%.热分析研究发现,由于空间位阻,接枝共聚物的结晶度较聚乙烯前驱体略有下降,且接枝度越大,结晶能力下降得越多.
[Abstract]:The hydroxyl terminated linear polyethylene was prepared by ethylene coordination polymerization and mercapto-vinyl click-chemical reaction. The hydroxyl content of the end was close to 100. The high efficiency reaction between acyl chloride and hydroxyl group was used. The hydroxyl-terminated polyethylene was converted into norbornene-terminated polyethylene macromonomer (PE-NB). The macromolecular monomer and norbornene (NB) monomer were synthesized by ring-opening translocation copolymerization with Grubbs II catalyst. The poly norbornene (PNB-g-PE) grafted copolymer with controllable molecular weight and composition was prepared by adjusting the feed ratio and feeding mode of the monomer. During random copolymerization, the conversion rate of macromonomer is close to 100. The weight average molecular weight of random graft copolymer is 1.79 脳 10 ~ (4) ~ (4) ~ 3.14 脳 10 ~ (4), the molecular weight distribution index is 2.09 ~ 2.60, and the mass fraction of polyethylene segment is 4.6 ~ (16. 8). The conversion rate of macromonomer is about 80%. The results of thermal analysis show that the crystallinity of the graft copolymer is slightly lower than that of the polyethylene precursor due to the steric resistance, and the higher the grafted degree is, the more the crystallinity decreases.
【作者单位】：化学工程联合国家重点实验室浙江大学化学工程与生物工程学院;
【基金】：浙江省自然科学基金(基金号LY16B040001) 国家自然科学基金(基金号21536011)资助项目
【分类号】：O632.12

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