用经验特性粘度方程研究聚苯乙烯热降解行为

STUDY ON THE THERMAL DECOMPOSITION OF POLYSTYRENE BY USING THE EXPERIENTIAL INTRINSIC VISCOSITY EQUATION

采用经验特性粘度方程表征聚苯乙烯(PS)的热降解可以大大简化试验过程。该方法只需测定一个溶液浓度下的增比粘度(η_(sp))、相对粘度(η_r)值就可以计算PS溶液的特性粘度[η],再用[η]求出其分子量,从而得出PS在热降解过程中分子量与温度、时间的关系。研究结果表明,PS的分子量随温度的升高、时间的加长呈线性关系降低;降解速度随温度的升高呈对数关系增大;当温度高于300℃时,热降解显著加快。这一结果与TC分析等方法的结论一致,说明用经验特性粘度方程来研究PS的热降解过程方法简便可行。

The thermal decomposition of polystyrene was characterized with the experiential intrinsic viscosity equation, and this method could greatly simplify the experiment process. With this method, the intrinsic viscosity of polystyrene solution could be mensurable using only a solution concentration of the polymer, and the polymer molecular weight calculated from the intrinsic viscosity of polystyrene, and the relation of the molecular weight of the polystyrene with temperature and time obtained in the process of thermal decomposition. The experimental result showed that the molecular weight of polystyrene was decreased linearly with temperature and time, and the decomposition rate increased in the order of logarithm with temperature; while the temperature exceeded 300℃, the decomposition rate increased greatly. This result is consistent with that of the TG analysis. It is concluded that the study of the thermal decomposition of polystyrene by using experiential intrinsic viscosity equation is feasible and convenient method.