The study of liquid-liquid transition of atactic polymethylmethacrylate by dielectric spectroscopy

Abstract

The existence of a liquid-liquid transition in atactic polymethyl methacrylate (PMMA) is confirmed by means of dielectric spectroscopy and DSC (differential scanning calorimetry) thermal analysis. From the point of view of thermodynamics, the appearance of the maximum value of the epsilon '-T curve at a temperature approaching the transition point is illustrated. The results of dielectric temperature dependence at low frequency and DSC thermal analysis demonstrate that for atactic PMMA there is a structural transition near 170 degrees C. The ordered structure is regionally distributed. The permittivity and/or conductivity are different in different regions, so that interfacial polarization occurs.<>