Electromechanical properties of cellulose derivatives with electrical function

本研究的目的是从纤维素衍生物中开发出具有电功能和环境友好的材料。研究了氰乙基羟乙基纤维素(CEHEC)的电性能和力学性能。主要研究结果如下：1)研究了取代度与介电常数的关系。随着氰基取代度的增加，CEHEC的介电常数增大。2)根据振动簧片法的共振曲线，计算了CEHEC在短路和开路情况下的机电耦合系数。开路测量给出的弹性常数对应于零弹性位移，而短路测量给出的常量对应于零电场。在干燥条件下和40%RH条件下测量了共振曲线。弹性比、Eop/Est值几乎大于1。ELAS…值短路时更多的TiC损耗因子(tanδ)几乎大于开路时的弹性损耗因子。但EOP/Est值与压电常数之间的关系尚不清楚。谐振频率随着连续测量次数的增加而降低，这是由于电动驱动器的温升导致了测量室内的温度升高。在每个温度下，连续测量和不连续测量的共振频率值几乎相同。根据干燥状态下的压电常数、介电常数和弹性常数计算机电耦合系数(K)，根据弹性常数Eop和Est计算机电耦合系数(KE)。K_E值大于K_E。3)热释电物质具有压电性。由于CEHEC的行为是压电性的，所以CEHEC应该是热释电的。未经高压极化处理的CEHEC薄膜表现出热释电特性。在高温区观察到热释电效应产生的电荷。有必要测量高压下样品的热释电行为。4)将不同DS的薄膜埋入土壤中。随着处理时间的延长，所有薄膜在土壤中逐渐分解，振动簧片法的共振频率降低。DS最低的公司分解最快。随着氰基取代度的降低，CEHEC膜更容易发生生物降解，土壤中的微生物可以对CEHEC膜进行降解。较少

The purpose of the present investigation is to develop electrically functional and environmentally friendly materials from cellulose derivatives. The electrical and mechanical properties of cyanoethylated hydroxyethyl-cellulose (CEHEC) were investigated. The results obtained were summarized as follows.1) Relationship between degree of substitution and values of the dielectric constants was investigated. With increase of degree of substitution by cyano group, the values of the dielectric constants of CEHEC increased.2) The electromechanical coupling factors for CEHEC were calculated from the resonance curve of vibrating reed method in the cases of short-circuit (st) and open-circuit (op). Open-circuited measurement gives the elastic constant corresponding to zero elastic displacement, while short-circuited one gives the constant to zero electric field. Resonance curves were measured at dry condition and 40%RH. Values of Elasticity ratio, Eop/Est were almost larger than 1. Values of elas … More tic loss factor (tan δ) at short-circuit were almost larger than those of the elastic loss factor at open-circuit. But relationship between values of Eop/Est and the piezoelectric constants was not clear. Resonance frequency decreased with increasing continuous measurements, because of temperature rise in the measuring chamber by the temperature rise of the electric driver. Values of resonance frequency at continuous measurements and discontinuous measurements were almost same at each temperature. The electromechanical coupling factor (K) was calculated from the values of piezoelectric, dielectric and elastic constants at dried condition and the electromechanical coupling factor (K_E) was calculated from both elastic constants, Eop and Est. The values of K_E were larger than those of K.3) Pyroelectric substance behaves piezoelectric effect. As CEHEC behaves as piezoelectric substance, CEHEC is expected to be pyroelectric. Pyroelectricity of CEHEC films was showed without applying high voltage poling treatment. Electrical charge produced by pyroelectric effect was observed at high temperature region. It is necessary that we measure pyroelectric behavior about specimens applied high voltage.4) The films of which DS were different were buried in soil. All films were gradually decomposed with increasing treated time in the soil, and resonance frequency of vibrating reed method decreased. The firms with the lowest DS decomposed most rapidly. It is recognized that biodegradation takes place easily with decrease of degree of substitution of cyano group and CEHEC film can be degraded by microorganisms in soil. Less