超支化聚乙烯接枝马来酸酐及其过程中交联和降解反应的抑制  

GRAFTING OF MALEIC ANHYDRIDE ONTO HYPERBRANCHED POLYETHYLENE AND SUPPRESSION OF CHAIN DEGRADATION AND CROSSLINKING SIDE REACTIONS

作　　者：邓昌付[1] 范宏[1] 郭春文[1] 李伯耿[1] 朱世平 

机构地区：[1]化学工程国家重点实验室(浙江大学)浙江大学化工系,杭州310027 [2]Department of Chemical Engineering,McMaster University,1280 Main Street West,Hamilton,Ontario,Canada L8S 4L7

出　　处：《高分子学报》2008年第5期435-442,共8页Acta Polymerica Sinica

基　　金：国家自然科学基金海外杰出青年基金(基金号20428605);国家自然科学基金(基金号20476090)资助项目

摘　　要：采用后过渡金属催化剂二-(2,6-二异丙基苯基)丁二亚胺溴化镍(IBNB),通过均相聚合法合成了高分子量和高支化度的超支化聚乙烯(HBPE).以二特戊基过氧化物(DTAP)为引发剂,研究了HBPE接枝马来酸酐(MAH)反应,并用N,N-二乙基肉桂酰胺(DECA)作为抑制剂,有效地抑制了接枝反应体系中的交联和降解副反应.接枝反应体系中分别加入相同摩尔量的DECA、N,N-二甲基乙酰胺、苯乙烯、3-(2-呋喃)丙烯酸、肉桂酸乙酯,通过比较接枝产物的凝胶含量和分子量,发现DECA抑制交联和降解副反应的效果最好,同时解释了DECA的作用机理.Hyperbranched polyethylene （HBPE） is a new type of polyethylene materials in addition to low-density polyethylene （LDPE）, high-density polyethylene （HDPE）, and linear low-density polyethylene （ LLDPE）. It has dendrimer-like compact globular structures. Due to lack of chain entanglements, it exhibits better solubility and lower viscosity than the other types of polyethylene. HBPE has attracted great attention in the recent years in both academic and industrial researches. However, as polyolefin materials, HBPE suffers from such shortcomings as nonpolar nature and thus lack of functionalities. These shortcomings limit its applications. Grafting of polar molecules such as maleic anhydride （MAH） has been widely adopted in the modification of polyolefins. In this work, HBPE samples having high molecular weight （Mw = 8 × 10^6 g/mol） and high branching density （the number of branches per 1000C = 108） were synthesized by solution polymerization of ethylene with a late transition metal catalyst, namely bi （2,6-diispropylphenyl） butane diimine nickel dibromide （IBNB） at 45 ℃ and 0.5 MPa. The Ni catalyst is well-known to experience a chain walking mechanism that is responsible for the hyperbranched chain topology. ^1H-NMR and ^13 C-NMR were used to examine the branching density and the type of branches, respectively. It was discovered that the types of branches were mainly methyl （50.54%） and butyl （20.30%）. MAH was grafted onto HBPE through a free radical mechanism. Di-tert amyl peroxide （DTAP） was used as the free radical initiator. However, it was found that the HBPE/MAH/DTAP grafting system experienced severe chain degradation and crosslinking side reactions during the grafting process. N, N-diethyl cinnamamide （DECA） was thus synthesized by the use of cinnamoyl chloride, diethylamine, and triethylamine which was used as an acid-binding reagent. DECA was then used as an inhibitor to suppress the side reactions. The approach was successful and efficient. The gel co

关 键 词：超支化聚乙烯 马来酸酐 接枝 交联 降解 DECA 

分 类 号：TQ316.343[化学工程—高聚物工业]