聚氨酯与铁电陶瓷粉复合物的电致感应性能研究

利用双辊制备了一系列热塑性弹性体聚氨酯（PU）和铁电钛酸锆酸铅盐（PZT）的电感应PZT／PU复合物。X－衍射和SE镜结果显示，复合物中，在铁电相中PZT陶瓷粉呈现结晶态并且均匀分布在PU基体中，复合物的弹性模量和相对电容率随着复合物中PZT体积分数增加而升高，在高压电场下，低PZT含量的复合物呈现负的电致伸缩应力，当PZT体积分数增加到6％以上时，在某个临界电场下，复合物呈现出电致伸缩应力反转的特性，即电致伸缩应力从负转变为正，并且发生应力反转的临界电场随着复合物中PZT体积分数的增加而降低，PU的电致伸缩特性与PZT在高电场下极化反转效应结合，导致了PZT／PU复合物这种有趣的性能，因此PZT／PU复合物将在高电压场方面作为传感器开关材料得到广泛应用。

Electrostriction of the Composites of Polyurethane with Ferroelectric Lead Zirconate Titanate Ceramic Particles

Electrostrictive composites of thermoplastic elastomer polyurethane (PU) and the ferroelectric lead zirconate titanate (PZT) with various volume fractions were prepared by hot roller miller. X ray diffraction results and SEM micrographs showed that the ceramic crystallized in the ferroelectric phase and was dispersed uniformly in the elastomer. The elastic modulus and dielectric permittivity increased with PZT volume fractions. For composites of low PZT volume fraction, negative electrostrictive strain (contraction) was observed. As the PZT volume fraction increased to be more than 6%, the composites exhibited a switching characteristic when the applied electric field was increased to be a critical value. The critical electric fields decreased with increasing PZT volume fractions. This effect can be explained as the resultants of the electrostriction of PU and polarization reversal of the PZT at high field. This interesting properties of the PZT/PU composite will lead to some switching actuations for high electric field applications.