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本文研究了 PVDF-P(VDF-HFE)以及 PVDF-P(VDF-TFE)共混体系的压电、介电、力学松弛谱。其松弛转变过程基本与 PVDF 的相似。α,β,γ压电松弛峰分别位于40～120℃,-40℃,-85℃附近。实验结果表明后一体系的压电性大于前一体系的。同时,PVDF-P(VDF-TFE)的压电性也大于PVDF-PMMA 共混体系的。选择第二组分时,以介电常数高,模量小而本身又具有压电性的,更有助于共混薄膜压电性的提高。在同样的极化条件下,经拉伸的 P(VDF-TFE)薄膜,其压电性大于未经拉伸的薄膜,这表明分子的取向对薄膜的压电性也有影响。TSC 表明,42℃的松弛峰与晶区表面捕获的空间电荷有关,对压电性也有一定的贡献。
In this paper, the piezoelectric, dielectric and mechanical relaxation spectra of PVDF-P (VDF-HFE) and PVDF-P (VDF-TFE) blends were investigated. The relaxation process is basically similar to PVDF. The α, β and γ piezoelectric relaxation peaks are located at 40 ~ 120 ℃, -40 ℃ and -85 ℃, respectively. The experimental results show that the piezoelectricity of the latter system is greater than that of the previous system. At the same time, the piezoelectricity of PVDF-P (VDF-TFE) is also greater than that of PVDF-PMMA blends. When the second component is selected, it is more conducive to improving the piezoelectricity of the blended film with high dielectric constant, small modulus and itself piezoelectricity. Under the same polarization condition, the stretched P (VDF-TFE) film has greater piezoelectricity than the unstretched film, indicating that the molecular orientation also has an effect on the piezoelectricity of the film. The TSC shows that the relaxation peak at 42 ° C is related to the space charge trapped on the surface of the crystal and contributes to the piezoelectricity.