Dielectric spectroscopy of some “biopol” polymers

In the present paper comparisons are drawn between data for the poly(β-hydroxybutyrate) (PHB) homopolymer and for a related poly(β-hydroxybutyrate-co-β-hydroxyvalerate) (PHBV). In measurements of complex relative permittivity for PHB and PHBV over wide ranges of frequency and temperature. four distinct loss regions are apparent, These are attributed respectively to carbonyl-driven local mode β-relaxations involving cooperative motions of methyl and ester groups in amorphous domains, to the α-relaxation process associated with the glass transition in the amorphous regions, to an polarization at the interface between crystalline and amorphous domains, and to the presence of phosphite residues