Structure-property interpretation of biological polyhydroxyalkanoates with different monomeric composition: Dielectric spectroscopy investigation

Dielectric spectroscopy is employed to study the relaxation phenomena in natural polyhydroxyalkanoates (PHAs) upon temperature and frequency variations. Effects of PHAsmolecular structure on the relaxation, arising from the differences in monomeric composition, are investigated under identical conditions in a frequency range of 10-2-106 Hz, and at different temperatures. All PHA samples showed different dielectric response at different temperature. Primary a-relaxation signals are observed at temperature corresponding to the glass transition temperature. On the other hand, secondary beta- and gamma-relaxations are detected at low temperatures, and attributed to localmotions of polar groups and small segments of the polymer chain. The dielectric properties of representative PHA samples are compared and discussed. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Dielectric spectroscopy was used to study relaxation phenomena in PHAs, revealing the effects of molecular structure and temperature on dielectric response. Primary α-relaxation signals were observed at glass transition temperature, while secondary β- and γ-relaxations were detected at low temperatures. Comparison and discussion of dielectric properties of representative PHA samples were conducted.