DIELECTRIC-RELAXATION OF POLY(BETA-HYDROXYBUTYRATE) RELATING TO MICROSTRUCTURE

Citation
I. Sics et al., DIELECTRIC-RELAXATION OF POLY(BETA-HYDROXYBUTYRATE) RELATING TO MICROSTRUCTURE, Journal of macromolecular science. Physics, B37(6), 1998, pp. 851-862
Citations number
24
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Polymer Sciences
ISSN journal
0022-2348
Volume
B37
Issue
6
Year of publication
1998
Pages
851 - 862
Database
ISI
SICI code
0022-2348(1998)B37:6<851:DOPRTM>2.0.ZU;2-0
Abstract
The dielectric relaxation behavior of a high molecular weight poly(P-h ydroxybutyrate) (PHB) synthesized through Azotobacter chroococcum 23 w as investigated by measuring the complex dielectric permittivity over wide frequency and temperature ranges. PHB exhibits two dielectrically active processes in the temperature and frequency ranges investigated . The higher temperature relaxation a has been attributed to motions t hat appear at temperatures above the glass transition temperature T-g. The low-temperature process beta is thought to be due to local motion of carboxyl groups and local rotations around the C-O bond. The pheno menological Havriliak-Negami (HN) description has been applied to anal yze the dielectric loss data and to extract the shape parameters of th e above relaxations in an attempt to correlate experimental data to dy namics of relaxation processes.