Structure and Properties of Cellulose Derivatives with Piezoelectricity, Pyroelectricity and Ferroelectricity

本研究的目的是开发纤维素衍生物的高压电性材料。并对纤维素衍生物的铁电性进行了研究。研究发现，氰乙基化的纤维素具有最高的压电系数。测定了硝酸纤维素、醋酸纤维素、氰乙基化纤维素和氰乙基化羟乙基纤维素的压电模。在20ﾟC时，氰乙基羟乙基纤维素的C/N约为1-2×10~(-1)~(-11)，是纤维素衍生物中最高的，已接近聚氟乙烯的值。通过增加压电率，有可能将其用作具有电功能的工业材料。测定了高压电模氰乙基羟乙基纤维素的D(电脱塑)-E(电场)磁滞回线。但我们无法从实验上证明氰乙基羟乙基纤维素中铁电性的存在。由于直流电流增大，不能对试件施加较高的电场。有必要去除离子和其他低分子量杂质。目前正在考虑用高拉伸取向或用强电场或强磁场取向极性侧链的纤维素衍生物的铁电性的测量。

The purpose of the present investigation is to develop the high piezoelectric materials of cellulose derivatives. And also the possibility of ferroelectricity of cellulose derivatives has been studied. It is recognized that cyanoethylated cellulose has the highest piezoelectric modulus in the cellulose derivatives.The results obtained are summarized as follows.1. Cellulose derivatives with high piezoelectric modulusThe piezoelectric modulu of cellulose nitrate, cellulose acetate, cyanoethylated cellulose and cyanoethylated hydoroxyethylcellulose have been measured. The value of cyanoethylated hydroxyethylcellulose is about 1-2x10^<-11> C/N at 20ﾟC.The value of it is the highest in the cellulose derivatives and is approaching the value of Polyvinyl fluoride. It may be possible to use it as industrial materials with electric functions by increasing the piezoelectric porlarization.2. Possibility of ferroelectric cellulose derivativesD(electric displasement)-E(electric field) hysteresis loop is measured about the cyanoethylated hidroxyethylcellulose whith high piezoelectric modulus. But we could not experimentally prove the existence of ferroelectricity in cyanoethylated hydroxyethylcellulose. Because of increasement of direct current, high electric field could not be applied to the specimens. It is necessary to remove ionic and other low molecular weight impurities. Measurements of ferroelectricity of cellulose derivatives which are oriented by high drawing, or of which polar side chains are oriented by high electric field or high magnetic field are now under consideration.