【作者】 汤敏敏；

【导师】 安振连；

【作者基本信息】 同济大学 ， 凝聚态物理， 2007， 硕士

【摘要】 聚丙烯孔洞膜（cellular PP）是近年来发现的一种具有重要商业应用前景的驻极体压电材料。然而，PP孔洞驻极体压电膜虽然满足高压电活性的要求，但其较低的电荷热稳定性使得其工作温度一般不能超过60℃，从而限制了其进一步的开发应用。因此，如何改善这种功能膜的储电及压电热稳定性是近年来倍受关注的课题。但是，仅靠物理的热老化或高温驻极等方法不能从根本上解决这一问题。为此，本论文首次提出并实施了化学改性对PP孔洞膜的储电和压电热稳定性的影响的研究。 本文首先通过热刺激放电（Thermally Stimulated Discharge，TSD）电流、原位实时电荷TSD和电荷等温衰减的测量，系统地研究了商用PP合成纸（国产PQ50型）原膜的驻极特性，分析了其电荷储存机制。红外分析和断面的X射线能谱分析表明，经过相继的化学处理（表面小分子萃取、氧化处理和氢氟酸处理）后，PP孔洞薄膜生成了具有一定深度的氟化层。利用电流TSD、电荷TSD、电荷等温衰减等方法对PP孔洞原膜和化学改性膜的储电性的对比性研究表明，化学改性的工艺过程及参数对PP孔洞膜的电荷热稳定性具有明显的影响，在优化的改性条件下制得的氟化膜的电荷稳定性与原膜相比得到了极为显著的提高。 此外，利用上述实验方法并结合压力膨化处理工艺、静态压电d₃₃系数及其衰减的测量等实验手段，本文还研究了上述化学改性对PP孔洞薄膜的压电性能和压电热稳定性的影响。实验结果发现经化学改性后，PP孔洞驻极体薄膜的压电热稳定性有了极大地提高。结合PP孔洞膜的压电理论模型，本文还分析了化学改性后其压电热稳定性提高的根源。 最后，本文还开展了利用强氟化剂—氟气（F₂）和二氟化氙（XeF₂）对PP孔洞薄膜的氟化改性研究及相应氟化膜的驻极体性能的初步研究。更多还原

【Abstract】 Cellular polypropylene (PP) film is one of the piezoelectric electret materials with important commercial application potential in recent years. Some commercial applications are already available from cellular PP films because of their strong piezoelectricity, but the rather low working temperature (60℃) restricts their further applications. Therefore, how to improve cellular PP films’ thermal stability of piezoelectricity and charge storage becomes one of the focuses in the field of the functional dielectric materials. But it is difficult to improve those properties significantly only by physical preparation methods such as heat treatment or being charged at elevated temperatures. In this thesis, a chemical method was firstly proposed and its influences on the thermal stability of piezoelectricity and charge storage of cellular PP films were investigated.Firstly, the electret properties of virginal cellular PP (PQ50) films were systematically studied by measuring the open-circuit thermally stimulated discharge (TSD) current spectra and charge TSD spectra. Then, cellular PP films were modified by extraction, oxidation and fluorination in a hydrofluoric acid (HF) solution. The results of the attenuated total reflection infrared (ATR-IR) spectrum for the surface layer and the energy-dispersive X-ray spectrum (EDS) for the cross section of the chemically modified cellular PP films indicted that a layer containing fluorine element was formed after chemical treatment and it had a considerable reaction depth. By the means of TSD current spectra, charge TSD spectra and isothermal charge decay measurements, the charge storage properties of the virginal and the chemically modified cellular PP films were comparatively investigated. The results pointed out that the technology and parameters of chemical modification have obvious effects on the thermal stability of charge storage of the cellular PP film. With optimized chemical modification, the thermal stability of charge storage of the cellular PP film was significantly improved in comparison with that of the virginal one.In addition, the influences of the above-mentioned chemical modification on the更多还原