Title :
Depolarization currents from some polyesters and polyurethanes
Author :
Diaconu, I. ; Ciobanu, C. ; Simionescu, C.I.
Author_Institution :
Inst. of Macromolecular Chem. ´´P. Poni´´, Jassy, Romania
Abstract :
Thermally stimulated depolarization currents from some polyesters (PS) and corresponding polyurethanes (PU) based on those polyesters were studied in the range of 230-480 K. Two and four or five relaxation processes were detected in PS and PU, respectively. The location and intensity of the relaxation peaks are dependent on the chemical structure of the PS. The relaxations in PS were associated with glass transition and melting processes. Additional relaxations observed in PU were related to the Maxwell-Wagner polarization and to the secondary thermal transition of microphases with various hard segment concentrations
Keywords :
dielectric polarisation; dielectric relaxation; glass transition (polymers); melting; polymers; thermally stimulated currents; 230 to 480 K; Maxwell-Wagner polarization; chemical structure; glass transition; hard segment concentrations; melting processes; microphases; polyesters; polyurethanes; relaxation peaks; relaxation processes; secondary thermal transition; thermally stimulated depolarisation currents; Amorphous materials; Bonding; Chemical processes; Chemistry; Glass; History; Hydrogen; Mechanical factors; Polarization; Temperature distribution;
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.1991.167285
