Viscoelastic,dielectric, and piezoelectric behavior of solid amylose

Complex elastic, dielectric, and piezoelectric properties were measured on amylose films as a function of temperature and moisture content at 10 Hz. The real part of the complex Young's modulus of films containing a small amount of moisture was larger than that of a dry film. Peaks in the imaginary parts of these complex response functions were observed at about ?80°C. The height of these peaks decreased when the specimen absorbed a little moisture. The activation energy for this peak as determined from an Arrhenius plot of the dielectric frequency dispersion was about 9.5 kcal/mole. This peak was ascribed to methylol rotation. The real part of piezoelectric e constant was shifted downwards when the specimen absorbed moisture. This was attributed to the instantaneous response in the case of a step function excitation. The structure of amylose was thought to be stabilized by moisture absorption, probably due to hydrogen bonding. The mechanism of methylol rotation was examined by dielectric measurements.