Structure and Relaxation of Cellulose Derivatives

本研究的目的是获得新的高压电常数的纤维素衍生物，并研究其弹性、介电和压电弛豫。研究了氰乙基纤维素的压电性。合成了新型含氟纤维素衍生物。研究了它们的压电性。纤维素衍生物的结晶度和取向度都很低。因此，与氰乙基纤维素相比，它们的压电常数很低，约为10^&lt；-13&gt；C/N，但可以认为，通过纤维素衍生物的高取向和结晶，有可能开发出高性能的压电材料。研究了纤维素衍生物的松弛行为。研究了醋酸纤维素、对甲苯磺酸纤维素、氰乙基纤维素、PDAF-氰乙基纤维素和PDAF-乙基纤维素等纤维素衍生物由于侧链作用而形成的分散体。三醋酸酯纤维素和二醋酸酯纤维素在侧链局部模式上存在差异。在三醋酸酯纤维素中，由于乙酰基，在-30ﾟC附近观察到了压电色散、介电温度和弹性温度色散；在二醋酸纤维素中，由于羟甲基基团，在-80ﾟC附近观察到了温度色散。在乙基纤维素和乙酸乙酯中观察到了压电模、介电系数和弹性系数的一次分散，在乙基纤维素中约为55ﾟC，在三醋酸酯中约为100ﾟC，在二醋酸酯中超过100ﾟC。由于纤维素衍生物的结晶度和取向度很低，我们无法测量它们的温度依赖性。测定了纤维素晶体的温度依赖性。在200ﾟ℃以上，纤维素晶体发生了垂直于分子链的突然热膨胀，可以认为纤维素晶体中存在温度弥散。

The purpose of this research is to obtain new cellulose derivatives with high piezoelectric constants and investigate the elastic, dielectric and piezoelectric relaxations. The piezoelectric properties of cyanoethyl cellulose have been investigated. New cellulose derivatives with fluorine were synthesized. The piezoelectricity of them was investigated. The degree of crystallinity and orientation of the cellulose derivatives were very low. And so the piezoelectric constants of them were very low compared with that of cyanoethyl cellulose which was of the order of 10^<-13> C/N. But it may be considered that there is a possibility of development of high piezoelectric materials from cellulose derivatives by high orientation and crystallization of them. The relaxation behaviors of cellulose derivatives are investigated. Dispersions due to side chain in cellulose derivatives are studied about cellulose acetate, cellulose tosylate, cyanoethyl cellulose, PDAF-cyanoethyl cellulose, and PDAF-ethyl cellulose. There was a difference between cellulose triacetate and cellulose diacetate in local mode of side chain. There was observed the piezoelectric, dielectric and elastic temperature dispersions at about -30ﾟC in cellulose triacetate due to acetyl group, and at about -80ﾟC in cellulose diacetate due to methylol group. There were observed the primary dispersions of the piezoelectric, dielectric and elastic moduli in ethyl cellulose and cellulose acetate, at about 55ﾟC in ethyl cellulose, at about 100ﾟC in cellulose triacetate, and above 100ﾟC in cellulose diacetate. Because the cellulose derivatives were very low at the degree of crystallinity and orientation, we could not measure the temperature dependency of them. The temperature dependency of cellulose crystals was measured. There was an abrupt thermal expansion perpendicular to molecular chain in cellulose crystals above 200ﾟC. It may be considered that there is the temperature dispersion in cellulose crystals.