自组织临界的OFC模型在聚丙烯介电弛豫中的应用

OFC Model of SOC Used to Dielectric Relaxation of PP

将自组织临界中OFC模型的能量传递概念及相关参量α引入极值动力学模型 ,得到了同时与KWW方程和幂律均相关的介电弛豫的函数关系。用时域介电谱方法测量了聚丙烯在 - 15～ 90℃慢极化电荷的释放过程 ,结果显示 :在较低温度 ,弛豫为幂律 ;在较高温度 ,弛豫随时间的增加从幂律过渡到KWW关系。理论分析与实验结果基本一致 ,由此可知KWW方程的参量 β反映了外界温度对材料弛豫单元的影响 ;参量a反映了能量传递的大小及温度的影响 ,当 β较小或a较大时 。

Concept of energy transfer from over-critical value elements and related parameter α in the OFC model of self-organized criticality (SOC) are introduced into the model of extreme value dynamics. The result of dielectric relaxation function shows a correlation both with KWW function and power law function. Time domain dielectric spectroscopy is used to measure the decay process of slow polarized charges of PP between -15℃ to 90℃. The results show that relaxation is power law in lower temperature and relaxation changes from power law to KWW function in upper temperature. Theoretic analysis and experimental results are consistent which imply the β of KWW function reflecting the influence of temperature on relaxation element of material and parameter a reflecting the amount of energy transfer and temperature. When β is lower or a is larger, power law relaxation is more distinct.