Title :
The study of liquid-liquid transition of atactic polymethylmethacrylate by dielectric spectroscopy
Author :
Liu, Yaonan ; Cao, Xiaolong
Author_Institution :
Dept. of Electr. Eng., Xi´´an Jiaotong Univ., China
fDate :
29 Oct-2 Nov 1989
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 ε´-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°C. The ordered structure is regionally distributed. The permittivity and/or conductivity are different in different regions, so that interfacial polarization occurs
Keywords :
dielectric polarisation; dielectric properties of liquids and solutions; dielectric relaxation; liquid-liquid transformations; polymer melts; polymer structure; thermal analysis; 170 C; DSC; atactic polymethylmethacrylate; dielectric relaxation; dielectric spectroscopy; interfacial polarization; liquid-liquid transition; low frequency; ordered structure; permittivity; structural transition; thermal analysis; Dielectric liquids; Dielectric measurements; Electrochemical impedance spectroscopy; Frequency measurement; Glass; Polymers; Temperature; Thermal conductivity; Thermal engineering; Thermodynamics;
Conference_Titel :
Electrical Insulation and Dielectric Phenomena, 1989. Annual Report., Conference on
Conference_Location :
Leesburg, VA
DOI :
10.1109/CEIDP.1989.69577
