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研究了偏氯乙烯-三氟乙烯共聚物与钛酸铅形成的铁电复合物PT/P[VDF(70)-TrFE(30)]的热释电流行为.P[VDF(70)-TrFE(30)]室温下存在两个铁电相,即较无序的铁电相和较有序的铁电相,升温经过各自的相转变点后转变成较有序的顺电相和较无序的顺电相.热释电流谱上出现在95℃和108℃的两个电流峰,分别由两个铁电相的结构陷阱以及部分取向的偶极所贡献.采用Tc以上温度极化并冷却到不同温度的方法可明确鉴别出该试样两个顺电相降温转变过程,转变点分别为62℃和50℃.实验证实陷阱仅存在于铁电相而不存在于顺电相中.钛酸铅的引入虽不导致新电流峰出现,但可使共聚物的Tc降低、电流加大.热释电流方法可非常灵敏地跟踪铁电共聚物的相变过程.
The thermolysis current behavior of PT / P [VDF (70) -TrFE (30)] ferroelectric composite formed by vinylidene chloride-trifluoroethylene copolymer and lead titanate was studied. P [VDF (70) -TrFE (30)] There are two ferroelectric phases at room temperature, namely the more disordered ferroelectric phase and the more ordered ferroelectric phase, and the temperature is changed to more after passing through the respective phase transition points Sequential paraelectric and less ordered paraelectric phases. The two current peaks at 95 ° C and 108 ° C appear on the pyroelectric current spectrum, which are contributed by the structural traps of the two ferroelectric phases and the partially oriented dipoles, respectively. Using the method of temperature polarization above Tc and cooling to different temperatures, two transition phases of paraelectric phase transition of the sample can be clearly identified. The transition points are 62 ° C and 50 ° C respectively. Experiments confirmed that the trap only exists in the ferroelectric phase and does not exist in the paraelectric phase. Although the introduction of lead titanate does not lead to the emergence of a new current peak, but can reduce the Tc copolymer, the current increase. The pyroelectric current method can very sensitively track the phase transition of the ferroelectric copolymer.