Title :
Dipolar thermal relaxation of oriented, crystallized and γ-irradiated PET electrets
Author :
Zhang, Xingyuan ; Zhou, Yiqin ; Jixiang Zhang
Author_Institution :
Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China
Abstract :
The motion of dipolar thermorelaxation for stretched, γ-irradiated and isothermal annealed semicrystalline poly(ethylene terephthalate) (PET) is investigated with the thermally stimulated current method. An α-peak of short-circuit thermally stimulated current is shifted to a higher temperature when the degrees of planar orientation and crystallinity are increased, and is shifted to a lower temperature when the γ-irradiation dose is increased. The activation energy of dipolar thermorelaxation for main-chain segmental motion in the amorphous region is decreased linearly and the time constant of dipolar thermal relaxation is enlarged exponentially with enhancing Δ(xy)z and Xc. The γ-irradiation does not have a pronounced effect on the activation energy and the time constant of dipolar thermal relaxation
Keywords :
dielectric relaxation; electrets; gamma-ray effects; molecular orientation; polymer structure; polymers; thermally stimulated currents; activation energy; alpha -peak; amorphous region; crystallinity; dipolar thermal relaxation; dipolar thermorelaxation; gamma -irradiated PET electrets; gamma -irradiation dose; isothermal annealed semicrystalline poly(ethylene terephthalate; main-chain segmental motion; oriented crystallised polymer; planar orientation; short-circuit thermally stimulated current; thermally stimulated current method; time constant; Amorphous materials; Annealing; Chemistry; Crystallization; Electrets; Glass; Heating; Optical films; Positron emission tomography; Temperature;
Conference_Titel :
Electrets, 1991. (ISE 7) Proceedings., 7th International Symposium on (Cat. No.91CH3029-6)
Conference_Location :
Berlin
Print_ISBN :
0-7803-0112-9
DOI :
10.1109/ISE.1991.167284
