Structure and electromechanical properties of cellulose derivatives with electrical function

点击翻译按钮获取中文摘要

The purpose of the present investigation is to develop electrically functional and environmentally friendly materials from cellulose derivatieves. The piezoelectricity of CEHEC were investigated.The results obtained were summarized as follows.1) Dependence of the piezoelectric, dielectric, and elastic constants on temperature was measured. Elastic, piezoelectric, and dielectric relaxations were observed between -80℃ and -60℃ and elastic and piezoelectric relaxations between 0℃ and 20℃ at a frequency of 10 Hz. The activation energies are about 9-15 kcal/mol in the low-temperature region and about 30-45 kcal/mol in the higher temperature region. These relaxations may be caused by the motion of the cyanoethyl group at low temperature and mostly by motions of the main chain at room temperature.2) Relationships between degree of substitution and values of the dielectric, elastic and piezoelectric moduli were investigated. With increase of degree of substitution by cyano group, the values of … More the dielectric, elastic and piezoelectric moduli of CEHEC increased.3) At room temperature CEHEC has a large piezoelectric constant, approximately 10ィイD1-11ィエD1 C/N, which is similar to the constant for polyvinylidene fluoride. The high level of piezoelectricity of CEHEC may be related to the orientation of the molecular chains with the polar cyano group during streching.4) The electromechanical coupling factor for CEHEC was small(4%). Dynamic moduli were measured by vibrating reed method in cases of which electric field E is zero and electric displacement D is constant. It was recognized that the value of dynamic modulus at the case of which D is constant is large compared with that of E=0. Also in the case of tangent loss tan δ, there was observed the difference between the case of D=const and E=0.5) The elastic constant of CEHEC film reduced slowly with increasing duration of the treatment in soil. It is recognaized that biodegradation takes place first with decrease of degree of substitution of cyano group and CEHEC film can be degraded by microorganisms in soil. Less