单茂钛/甲基铝氧烷催化剂乙烯/丙烯共聚合研究  

COPOLYMERIZATION OF ETHYLENE AND PROPENE WITH MONOTITANOCENE/ METHYLALUMINOXANE AS CATALYST

作　　者：祝方明[1] 杨益嘉[1] 林尚安[1] 

机构地区：[1]中山大学化学与化学工程学院高分子研究所,广州510275

出　　处：《高分子学报》2005年第3期413-416,共4页Acta Polymerica Sinica

基　　金：国家自然科学基金资助项目 (基金号 2 0 1740 5 0 );广东省自然科学基金资助项目 (基金号 0 3 9184)

摘　　要：改性甲基铝氧烷(mMAO)激活五甲基茂基三氯化钛(Cp TiCl3)催化乙烯 丙烯共聚合,控制两种单体的进料配比,得到单元序列分布不同的共聚物.混合单体中含有少量丙烯,共聚合活性高于相同聚合条件下乙烯均聚合的活性.用1 3C -NMR测定共聚物分子链的微观结构和单元序列分布,计算出单体的竞聚率;结果表明共聚物分子链中两种单体的序列分布均匀.混合单体中丙烯含量较大时,共聚物为完全无规共聚物;而当丙烯含量少时,丙烯链节或短的聚丙烯链段均匀分布于聚乙烯链段之间.共聚物经DSC分析,也证明不存在长序列的聚乙烯链段;因此,即便在进料气体中丙烯含量很少的情况下,共聚物仍然没有明显的熔融温度和结晶性.Ethylene and propene were homo- and copolymerized with monotitanocene catalyst composed of eta(5)-pentamethylcyclopentadienyltrichloride titanium (Cp * TiCl3) activated by modified methylaluminoxane (mMAO). Influences of copolymerization conditions including ethylene/propene molar ratio in the feeding, polymerization temperature and AIM molar ratio on activity, propene content in copolymers and the triad and tetrad sequence distributions were investigated. The monomer reactivity ratios r(E) and r(P) (E = ethylene, P = propene) for ethylene/propene copolymerizations were estimated from the C-13-NMR spectra. At high propene content in the feeding, the Cp * TiCl3/mMAO catalyst gave rise to r(E)r(P) approximate to 1 in combination with a resultant random copolymer. Whereas, at low propene content in the feeding, the copolymer exhibits a tendency toward alternating comonomer distribution (r(E)r(P) < 1) which indicates that propene suquences are isolated in the copolymer. The thermal properties of copolymers determined by DSC are mainly dependent on the propene content in the copolymers.

关 键 词：甲基铝氧烷 共聚合 催化剂 单茂钛 ^13C-NMR 序列分布 混合单体 聚乙烯链 无规共聚物 DSC分析 三氯化钛 进料配比 聚合条件 聚合活性 微观结构 均匀分布 熔融温度 分子链 五甲基 均聚合 竞聚率 含量 聚丙烯 结晶性 单元 

分 类 号：O631.5[理学—高分子化学]