茂金属催化聚合的聚1-丁烯的结构表征

以 η5 五甲基茂基三苄氧基钛 (Cp Ti(OBz) 3 和改性甲基铝氧烷 (mMAO)为催化剂 ,合成立体嵌段聚 1 丁烯 ,分子量高 ,分子量分布窄 ( Mw/ Mn=1 1～ 1 2 ) .聚合产物经沸乙醚、沸庚烷连续抽提分离 ,聚合物在两种溶剂中都能部分溶解 .各级份经13C NMR ,WAXD ,DSC和GPC等手段分析 ,结果表明乙醚可溶级份是无规聚 1 丁烯 ,庚烷可溶级份是立体嵌段聚 1 丁烯 ,庚烷不溶级份是等规聚 1 丁烯 .聚合温度较低 (0℃和30℃ )时 ,聚合物有结晶性 ,结晶度达 30 %以上 ,DSC分析有两个吸热峰 ;聚合温度较高 (4 0℃ )时 ,聚合物无结晶尖锐X射线衍射峰 ,也无熔融吸热峰 .

STRUCTURE AND CHARACTERIZATION OF POLY(1-BUTENE) FROM POLYMERIZATION WITH METALLOCENCE CATALYST STRUCTURE AND CHARACTERIZATION OF POLY(1-BUTENE) FROM POLYMERIZATION WITH METALLOCENCE CATALYST

A stereo-block poly(1-butene) was synthesized with η5-pentamethylcyclopentadienyltribenzyl-oxidetitanium(CpTi(OBz)3) and modified methylaluminoxane(MAO) as catalyst.The original polymer was extracted successively by boiling ether and heptane, and each fraction was characterized by 13C-NMR, WAXD and DSC. It was found that ether soluble fraction was atactic poly(1-butene), heptane solube fraction was stereo-block poly(1-butene), and heptane insoluble fraction was isotactic one. The isotacticity, glass transition temperature and crystallinity of the polymers soluble in boiling heptane were increased with decreasing polymerization temperature. At lower polymerization temperature (30℃ and 0℃),the polymers with the degree of crystallinity over 30% had two melting peaks which were 43℃／55℃ and 85℃／88℃, respectively. But at higher temperature(40℃), noncrystalline polymer obtained from heptane-solube fraction was characterized by WAXD and DSC. The relationship between the propagation mechanism and the microstructure of the prepared products was studied by 13C-NMR. It was indicated that the 1,2-insertion was easier than 2,1-insertion.