Capacitors and sensors based on polymer dielectric materials are key components in electrical systems and electronic devices. Considering the temperature rise during operation, an effective evaluation method for the thermal ageing of polymer matrix is urgently needed. P(VDF-HFP) film with a thickness of 20 μm is manufactured by solution casting and a thermal ageing experiment up to 1000 h is conducted. Dielectric responses of wide ranges of temperatures and frequencies are measured for samples with different ageing durations. The universal relaxation law and Dissado–Hill dielectric response model are applied to further investigate the results. The characteristics of individual processes are obtained, which demonstrate that the main chain relaxation following the Vogel−Fulcher−Tammann equation and side chain relaxation following the Arrhenius equation both remain unchanged after thermal ageing. However, the activation energies of those two processes change significantly during the process and show different variation trends. The activation energy of the side chain relaxation gets larger monotonically due to the influence of annealing and the breaking of crystalline region. As a result, a non-destructive evaluation method for the thermal ageing of P(VDF-HFP) is proposed accordingly.

中文翻译：

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基于宽带介电响应的P(VDF-HFP)薄膜热老化无损评价

基于聚合物介电材料的电容器和传感器是电气系统和电子设备中的关键部件。考虑到运行过程中的温升，迫切需要一种有效的聚合物基体热老化评价方法。P采用溶液流延法制备了厚度为20 μm的(VDF-HFP)薄膜，并进行了长达1000 h的热老化实验。对于具有不同老化持续时间的样品，测量了宽范围温度和频率的介电响应。应用通用弛豫定律和 Dissado-Hill 介电响应模型进一步研究结果。获得了各个过程的特征，这表明遵循 Vogel-Fulcher-Tammann 方程的主链弛豫和遵循 Arrhenius 方程的侧链弛豫在热老化后均保持不变。然而，这两个过程的活化能在过程中发生了显着变化，并表现出不同的变化趋势。由于退火和晶区断裂的影响，侧链弛豫的活化能单调变大。因此，一种热老化的无损评价方法P（VDF-HFP）据此提出。