The dielectric relaxation behavior of a high molecular weight poly(β-hydroxybutyrate) (PHB) synthesized through Azotobacter chroococcum 23 was 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 α has been attributed to motions that appear at temperatures above the glass transition temperature T g. The low-temperature process β is thought to be due to local motion of carboxyl groups and local rotations around the C─O bond. The phenomenological Havriliak-Negami (HN) description has been applied to analyze the dielectric loss data and to extract the shape parameters of the above relaxations in an attempt to correlate experimental data to dynamics of relaxation processes.
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Šics et al. (1998) studied this question.
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