摘要
通过乙丙共聚物的原位交联,可以降低其分子链运动性,从而在丙烯多相共聚过程中,实现对合金相形貌的控制.但在Ziegler-Natta催化剂体系中,长碳链的非共轭α,ω-双烯烃在促进交联的同时,伴随着悬垂双键结构的形成,其对原位交联效果的影响尚不清楚.本文选用9,9-二(甲氧基甲基)芴为内给电子体的MgCl2/TiCl4催化剂,1,9-癸二烯为交联剂,合成了系列乙丙共聚物,通过对链结构和流动性的分析发现,交联结构的形成明显滞后于悬垂双键,且乙丙共聚物流动性随1,9-癸二烯浓度增加呈现不规则的U型变化:当1,9-癸二烯浓度小于0.22 mol/L时,乙丙共聚物流动性增强;当浓度高于0.22 mol/L时,流动性受限.本研究对以非共轭α,ω-双烯烃控制丙烯多相共聚反应和新型聚丙烯反应器合金的合成有一定指导作用.
In heterophasic copolymerization of propylene to high-impact PP copolymer,an emerging approach to control of the all-important copolymer particle morphology is in situ crosslinking the ethylene-propylene copolymer(EPR)by nonconjugatedα,ω-diolefin.With the formation of crosslinking structure,pendant unsaturation structure supervened and its role was unveiled.This paper discusses the effect of pendant unsaturation structure on EPR’s flowability.A series of EPR samples with increasing crosslinking degrees were synthesized by an MgCl2/9,9-bis(methoxymethyl)fluorene/TiCl4 catalyst and 1,9-decadiene of increasing concentrations.The copolymers were characterized by NMR,GPC,and DSC for chain structure,small amplitude oscillatory shear for linear viscoelasticity,and creep rheology for flowability.Increasing 1,9-decadiene concentration increased the EPR crosslinking degree monotonously;nevertheless,its effect on viscoelasticity was rather complex.Chain structure analyses reveal that in terms of effect on viscoelasticity,two opposite reaction processes are in progress in ethylene/propylene copolymerizaiton with in situ crosslinking by 1,9-decadiene,one being crosslinking itself,the other the accompanying fomation of pendantα-olefin unsaturations which are short chain-branching in essence.It is perceived that the sluggishness of Ziegler-Natta catalyst to sterically bulkyα-olefin makes the progression of crosslinking lag behind that of short chain-branching,which accounts for the peculiar U-shape in EPR flowability and 1,9-decadiene concentration relation.
作者
刘洋
秦亚伟
王莉
义建军
董金勇
Yang Liu;Ya-wei Qin;Li Wang;Jian-jun Yi;Jin-yong Dong(Key Laboratory of Engineering Plastics,Institute of Chemistry,Chinese Acadamy of Sciences,Beijing 100190;University of Chinese Acadamy of Sciences,Beijing 100049;Institute for Petrochemical Research,PetroChina Company Limited,Beijing 102206)
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2020年第9期1050-1058,共9页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号21574143,51973224)资助项目
作者简介
通讯联系人:董金勇,E-mail:jydong@iccas.ac.cn
