聚合级间戊二烯单体的分离及其离子聚合探索

Separation and ionic polymerization of polymer grade 1,3-pentadiene

利用二次萃取精馏方法对粗间戊二烯(PD)产品进行提纯,可得到高纯度(大于99%)的反式PD(EP)和顺式PD(ZP)。以PD异构体为聚合单体,分别以正丁基锂和Ti Cl4/CF3COOH为引发剂进行了阴离子和阳离子聚合,利用1H NMR,GC和GPC等方法分析了聚合反应特点。实验结果表明,阴离子聚合可实现PD异构体的活性可控聚合,聚合产物的相对分子质量及其分布可控,副反应可严格控制。阳离子聚合可获得高线型高不饱和度聚合物,但聚合过程可控程度不佳。PD异构体的离子聚合产物均以高反式1,4-结构为主,1,2-结构次之,基本无3,4-结构。正丁基锂引发阴离子聚合时ZP活性高于EP,TiCl4/CF3COOH引发阳离子聚合时EP活性高于ZP。推测PD的离子聚合机理为两性离子态聚合机理。

High-purity trans/cis-isomers(EP/ZP)of 1,3-pentadiene(PD)were achieved using continuous extractive distillation to refine crude PD.With PD isomers as monomers,anionic and cationic polymerizations were performed with n-BuLi and TiCl4/CF3COOH as initiators,respectively.Polymerization characteristics were studied by 1H NMR,GC and GPC.The results show that by anionic polymerization,living and controllable polymerization of PD isomers is achieved,and relative molecular mass and its distribution and by-reaction could be controlled;by cationic polymerization,high linear and high degree of saturation polymer could be produced,but the controllable degree of polymerization process is not good.The polymerization product of PD isomers is mainly 1,4-structure,then 1,2-structure,and little 3,4-structure.The activity of ZP is higher than EP when anionic polymerization is initiated by n-BuLi.Meanwhile,the activity of EP is higher than ZP when cationic polymerization is initiated by TiCl4/CF3COOH.The possible ionic polymerization mechanism of PD isomers is zwitterion forms mechanism of PD isomers.