新型压电共聚物P(VDF-HFP)薄膜驻极体

The New Piezoelectric Copolymer of P(VDF-HFP) Film Electret

通过正负电晕极化、热刺激放电电流谱(TSD)、激光振动测量与分析等方法,研究了用流延法制备的经过机械热拉伸前后的两种不同HFP含量(HFP含量分别为4.7%和5.9%)新型共聚物薄膜的驻极体特性.实验结果说明,拉伸前后的这类共聚物薄膜均是极性材料,即充电极化后的材料内部同时存在取向偶极子和俘获空间电荷.正电晕极化较负电晕极化更能提高偶极电荷和空间电荷的热稳定性.对样品实施的机械热拉伸工艺能显著增强材料的极化强度,即不仅增加了取向偶极子的浓度,而且空间电荷的储存密度也大大上升;同时在一定程度上改善了空间电荷的热稳定性.但HFP含量的上升则显著降低了偶极子取向强度和空间电荷的俘获能力.HFP含量为4.7%的共聚物薄膜具有高达133pm/V的逆压电d33系数.

The electret properties of the two kinds of casting prepared P(VDF-HFP) copolymer films whose content of HFP is 4.7% and 5.9% respectively were discussed by positive and negative corona charging, open circuit thermally stimulated discharge (TSD) and Laser Doppler Vibrometer. Experimental results point out that the said copolymer electret film is a polar material, i.e. there exist both oriented dipoles and deposited space charges in the film after charging. Positive corona charging have a better effect on th...