期刊
CHINESE JOURNAL OF POLYMER SCIENCE
卷 39, 期 9, 页码 1185-1190出版社
SPRINGER
DOI: 10.1007/s10118-021-2583-2
关键词
DMAO; Syndiotactic polystyrene; Styrene; Ethylene; Copolymerization
资金
- National Natural Science Foundation of China [51773193, 52073275]
The catalytic performance of rare-earth metal dialkyl complexes in combination with DMAO for styrene polymerization was investigated, with certain complexes showing high catalytic activity and selectivity. Moreover, the system was found to be effective for the polymerization of other styrene derivatives and the copolymerization of ethylene and styrene.
The catalytic performance of rare-earth metal dialkyl complexes in combination with DMAO (dry methylaluminoxane) is explored. In the presence of 60 equivalents of DMAO, the half-sandwich complex (C13H8CH2Ph)Sc(CH2SiMe3)(2)(THF) (1) is inert for styrene polymerization, but (C5Me4Ph)Sc(CH2C6H4NMe2-o)(2) (2) converts 18% styrene into syndiotactic polystyrene. Under the same conditions, the constrained-geometry configuration sandium complex (C13H8CH2Py)Sc(CH2SiMe3)(2) (3a) displays extremely high catalytic activity (>6420 kg.mol(Sc)(-1).h(-1)) and perfect syndiospecific (rrrr>99%) for styrene polymerization, while its lutetium (3b) and yttrium (3c) analogues are nearly inactive. Although the binary catalytic system 3a/DMAO exhibits very low activity for 4-methoxystyrene polymerization, it is an efficient catalyst for the syndioselective polymerization of other styrene derivatives such as 2-methoxystyrene, 4-methylthiostyrene, 4-fluorostyrene, 4-dimethylhydrosilylstyrene, alkynesusbstituted styrenes and 4-methylstyrene. In addition, the binary system 3a/DMAO can copolymerize ethylene and styrene to give alternating copolymers with a single glass transition at 80 degrees C and 0.4 MPa ethylene pressures. By increasing styrene feed amount from 20 mmol to 60 mmol, the styrene content slight increases from 48.2 mol% to 53.8 mol%, but the polymerization activity is obviously promoted from 240 kg.mol(Sc)(-1).h(-1) to 532 kg.mol(Sc)(-1).h(-1).
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据