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

点击翻译按钮获取中文摘要

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).