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电功能材料。研究了纤维素衍生物的高压电性和铁电性的可能性，发现氰乙基化纤维素具有最高的压电模量。主要研究结果如下：1.氰乙基化羟乙基纤维素的高压电模量和机电耦合系数硝酸纤维素的压电模量。已经测量了乙酸纤维素、氰乙基化纤维素和氰乙基化羟乙基纤维素。氰乙基化羟乙基纤维素在20 ℃时的值约为1-2*10^<-11>C/N。它的值在纤维素衍生物中最高，与聚氟乙烯的值几乎相同。有可能作为具有电功能的工业材料。机电耦合系数K被认为是评价压电材料性能的重要品质因数。压电常数与机电耦合系数之间存在线性关系。与聚偏氟乙烯的K值相比。氰乙基化羟乙基纤维素的溶解度很小，在4%以下。铁电纤维素衍生物的可能性氰乙基化羟乙基纤维素和苄基纤维素在实验上不能证明铁电性的存在。纤维素衍生物在强电场或强磁场作用下的铁电性的测量正在研究中。并研究了氰乙基化羟乙基纤维素的热释电性。但氰乙基化羟乙基纤维素的热释电性并不明显。虽然我们可以观察到P（VDF/TrFE）的热电性。

The purpose of the present investigation is to develop electrically functional materials of cellulose derivatives. High piezoelectricity and also the possibility of ferroelectricity of cellulose derivatives have been studied, It is recognized that cyanoethylated cellulose has the highest piezoelectric modulus in the cellulose derivatives. The results obtained are sumarized as follows.1. High piezoelectric modulus and electromechanical coupling factor of cyanoethylated hydroxyethylcelluloseThe piezoelecric moduli of cellulose nitrate. cellulose acetate, cyanoethylated cellulose and cyanoethylated hydoroxyethylcellulose have been measured. The value of cyanoethylated hydroxyethylcellulose is about 1-2*10^<-11> C/N at 20ﾟC.The value of it is the highest in the cellulose derivatives and is almost the same to the value of Polyvinyl fluoride. It may be possible to use it as indusyrial materials with electric functions. Electromechanical coupling factor K is considered as an important figure of merit in estimating the properties of the piezoelectric materials. There is a linear relationship between piezoelectric constant and electromechanical coupling factor. Compared with the K value of the polyvinylidene fluoride. that of cyanoetylated hydroxyethylcellulose is very small and under 4%.2. Possibility of ferroelectric cellulose derivativesWe could not prove the existence of ferroelectricity in cyanoethylated hydoroxyethyl-cellulose and benzyl cellulose experimentally. Measurements of ferroelecricity of cellulose derivatives oriented by high electric field or high magnetic field are now under consideration. And pyroelectricity of cyanoethylated hydroxyethylcellulose was examined. But we could not recognized the pyroelectricity of cyanoethylated hydroxyethyl-cellulose. though we can observed the pyroelectricity of P (VDF/TrFE).