Polypropylene (PP) is a widely used common type of polymer with excellent chemical and mechanical properties. Thermal aging is a main culprit in degrading its lifetime and effectiveness. In this article, terahertz (THz) dielectric frequency response of PP during the process of thermal aging is monitored and analyzed to understand the underlying mechanism and to qualify THz dielectric spectroscopy as a useful tool for time-stamping and benchmarking the thermal aging of polymer materials. Using an improved THz material parameter extraction algorithm for thin films, the real and imaginary parts of the dielectric permittivity of standard PP test coupons were obtained at various stages of the thermal aging process. In agreement with theoretical analysis based on a molecular-level understanding of the thermal aging dynamics, the experimental results indicated THz wave transmission loss of PP correlated quantitatively with the degree of its thermal aging.

中文翻译：

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基于太赫兹介电光谱的聚丙烯热老化分析

聚丙烯（PP）是一种广泛使用的常见聚合物，具有优异的化学和机械性能。热老化是降低其使用寿命和有效性的罪魁祸首。在本文中，PP 在热老化过程中的太赫兹 (THz) 介电频率响应被监测和分析，以了解其潜在机制，并将太赫兹介电光谱作为聚合物材料热老化的时间戳和基准测试的有用工具。 . 使用改进的太赫兹薄膜材料参数提取算法，在热老化过程的各个阶段获得了标准 PP 试件介电常数的实部和虚部。与基于对热老化动力学的分子水平理解的理论分析一致，