共聚物
苯乙烯
甲基铝氧烷
高分子化学
乙烯
单体
聚合
差示扫描量热法
玻璃化转变
材料科学
活化能
化学
催化作用
茂金属
聚合物
物理化学
有机化学
复合材料
物理
热力学
作者
Friedrich G. Sernetz,Rolf Mülhaupt,Robert M. Waymouth
标识
DOI:10.1002/macp.1996.021970325
摘要
Abstract Styrene was copolymerized with ethylene using Me 2 Si(Me 4 Cp)( N‐tert ‐butyl)TiCl 2 /methylaluminoxane (Me = methyl, Cp = cyclopentadienyl) varying monomer concentration, styrene/ethylene molar ratio and polymerization temperature. Increasing styrene or decreasing ethylene concentration, respectively, in the monomer feed lowered both activity of the catalyst system and molecular weight of the copolymer. Only at low styrene content, a linear correlation of styrene concentration in the monomer feed and styrene incorporation in the copolymer was found. From copolymerizations at various temperatures the activation energy of the insertion step was calculated to be 56 kJ/mol. According to Fineman‐Ross plot, the copolymerization parameters are r E = 23,4 for ethylene and r S = 0,015 for styrene. Investigation of the thermal properties by means of differential scanning calorimetry and dynamic mechanical analysis revealed pronounced decrease of melting temperature and increase of glass transition temperature with increasing styrene content.
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