聚烯烃化合物电老化中的电子动力学机理

MACHANISM OF ELECTRONIC DYNAMICS IN ELECTRICAL AGEING OF POLYOLEFINE COMPOUNDS

应用一级陷阱和复合方程、聚合物裂解反应,在聚合物电老化过程中推导了单体和自由基产生率的表达式;假定单体和自由基达到一定浓度作为击穿的临界条件,导出了聚烯烃化合物电老化的寿命公式,给现有的电老化经验公式赋于了物理化学意义;进一步发展了聚合物击穿的陷阱理论.文中以聚丙稀薄膜为试样,在真空中加速电老化,采用红外光谱分析和电子顺磁共振仪,研究了击穿场强、化学结构变化与电老化时间的关系,验证了上列的理论推导.

In this paper using the first-order trapping and the recombination of the equations of electrons and holes, the equations for creation of monomers and radicals during the electrical ageing have been derived. Assuming that the increase in concentration of monomers or radicals to a certain value is the breakdown criterion of samples,the life time of electrical ageing in polyolefine compounds has been found. The physical and chemical explanations for the present empirical equation of electrical ageing are discovered, and the trap theory of polymer breakdown is developed further. With the PP film as samples,the accelerating test of electrical ageing is taken in vaccum. Using the IR and EPR spectrum, the dependence of dielectric strength and chemical structure on electrical ageing time is investigated. The theoretical analysis is consistent with the test results.