Electromechanical properties of cellulose derivatives with electrical function

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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