聚合
化学
活化能
预聚物
高分子化学
碳酸二苯酯
聚合物
双酚A
双酚
动力学
反应速率
反应速率常数
扩散
酯交换
物理化学
热力学
有机化学
催化作用
环氧树脂
物理
聚氨酯
量子力学
作者
Chunmei Shi,Stephen M. Gross,Joseph M. DeSimone,Douglas J. Kiserow,George W. Roberts
出处
期刊:Macromolecules
[American Chemical Society]
日期:2001-02-28
卷期号:34 (7): 2060-2064
被引量:23
摘要
The kinetics of solid-state polymerization (SSP) of poly(bisphenol A carbonate) was investigated with N2 as the sweep gas. The N2 flow rate and prepolymer particle size were chosen to eliminate the influence of both external and internal phenol diffusion, and to ensure that the kinetics was controlled by the rate of the forward transesterification reaction. The forward reaction rate constants were evaluated at different temperatures between 120 and 165 °C, and the activation energy for SSP of poly(bisphenol A carbonate) with N2 as the sweep gas was determined to be 99.6 kJ/mol. At each temperature, the polymer molecular weight increased with time, eventually reaching an asymptotic value. The asymptotic molecular weight increased with temperature. The glass transition temperature (Tg) of the polymer increased as the molecular weight increased. At lower reaction temperatures, Tg approaches the reaction temperature as the polymerization proceeds, and the achievable molecular weight appears to be limited by decreased end group mobility. At the highest reaction temperature, which was well above the final Tg of the polymer, the stoichiometric ratio of the two end groups appears to determine the achievable molecular weight.
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