Piezoelectric effect of cyanoethylated hydroxyethylcellulose

The piezoelectricity of cyanoethylated hydroxyethylcellulose was investigat ed. Elastic, piezoelectric, and dielectric relaxations were observed at -80 degrees to -60 degrees C and 0 degrees to 20 degrees C at a frequency of 1 0 Hz. The activation energy is about 9-15 kcal/mol in the low temperature r egion and about 30-45 kcal/mol at room temperature. These relaxations in th e low temperature region may be caused by the motion of the cyanoethyl grou p and those at room temperature mostly by the motions of the main chain. Cy anoethylated hydroxyethylcellulose has a high piezoelectric strain constant (d(25)), which is the largest value among the cellulose derivatives and is almost the same as the value for polyvinylidene fluoride. The electromecha nical coupling factor for cyanoethylated hydroxyethylcellulose was small.