温度对PEEK太赫兹光谱特性影响研究

聚醚醚酮（PEEK）由于其耐热、耐腐蚀、耐辐照、抗疲劳、电绝缘性等优良性能，在许多领域可以代替金属、陶瓷等传统材料而得到广泛应用。特别是随着5G技术的发展和应用，PEEK已经成为5G热门材料。在PEEK材料实际应用中，温度的影响是一个非常重要和关键的因素。主要研究了PEEK太赫兹光谱以及温度对PEEK太赫兹光谱特性的影响。通过利用太赫兹透射光谱技术，同时结合控温装置，在温度从25～300 ℃均匀上升过程中，每间隔5 ℃测试得到PEEK片状样品的太赫兹时域光谱数据，利用光学参数提取算法可以得到PEEK的吸收系数、介电常数等光学参数，进一步得到特定频率下光学常数随温度的变化趋势，从而对材料进行表征和分析。在0.5～4 THz有效光谱范围内，实验结果表明，在常温（25 ℃）下，PEEK在3.5 THz具有一个明显的特征吸收峰。在25～300 ℃这个温度范围内，在1 THz频率下，PEEK的吸收系数、介电常数相对于室温分别有4.38%和5.0%的波动，同时PEEK在常温下在1 THz的介电损耗正切值为2.5×10-3，相比于PMMA和PE等高分子材料，PEEK的介电损耗正切值要低得多，且在升温过程保持相对稳定，表明PEEK在太赫兹频段的光谱特性具有很好的热稳定性和较低的介电损耗。研究结果表明，太赫兹光谱技术可以结合温控装置，通过材料的光学参数对高分子材料热稳定性进行研究和表征，同时还可以得到材料在不同温度下的介电性质。太赫兹光谱技术具有快速、高效、无标记、无损伤等优势，只需要压片就可以对固体样品进行测试，对于研究材料内部缺陷、稳定性以及材料的鉴别等具有很好的研究意义。同时本实验的测试数据可以为PEEK材料在不同温度下5G和6G等高频通信应用提供参考。

Temperature Effects on the Terahertz Spectral Characteristics of PEEK

Poly-ether-ether-ketone (PEEK) can replace traditional materials such as metals and ceramics in many fields and is widely used due to its excellent properties such as heat resistance, corrosion resistance, radiation resistance, fatigue resistance, and electrical insulation. Especially with the development and application of 5G technology, PEEK has become a popular material for 5G. Temperature is an important and key factor to affect the application of PEEK materials. This work studied the Terahertz (THz) spectroscopic characteristics of PEEK and their dependences on the temperature. It is using terahertz transmission spectroscopy, combined with a temperature control device, THz time-domain spectral signals of the PEEK flake sample were measured every 5 ℃ in the temperature range from 25 to 300 ℃ with a constant temperature increasing speed. THz absorption coefficient, dielectric constant and other optical constants of the PEEK flake can be obtained with the optical constant extraction algorithm. The temperature dependence of these THz spectroscopic parameters on the temperature was analyzed. In the effective spectral range of 0.5～4 THz, the experimental results show that at room temperature (25 ℃), PEEK has a distinct characteristic absorption peak at 3.5 THz. At the temperature range of 25～300 ℃, at 1 THz frequency, the absorption coefficient and the dielectric constant of PEEK have a fluctuation of 4.38% and 5.0%, respectively, relatively to room temperature. At room temperature, the PEEK at 1 THz has a dielectric loss tangent value of 2.5×10-3. Compared to PMMA, PE and other polymers, the dielectric loss tangent value of PEEK is much lower; At the temperature range of 25～300 ℃, it remains relatively stable with a small fluctuation during heating, indicating excellent thermal stability and low dielectric loss of PEEK. The results in this work show that terahertz spectroscopy can be combined with a temperature-controlled device to study and characterize the thermal stability of polymer materials through the optical constants of the materials and obtain the dielectric properties of the materials at different temperatures. Terahertz spectroscopy is fast, efficient, label-free and non-destructive, and it can be used to study the internal defects, stability, and identification of materials. Simultaneously, the test data in this work can provide a reference for PEEK material applied in 5G, 6G, and other high-frequency communications at different temperatures.