Dielectric spectroscopy of some "biopol" polymers

In the present paper comparisons are drawn between data for the poly(/spl beta/-hydroxybutyrate) (PHB) homopolymer and for a related poly(/spl beta/-hydroxybutyrate-co-/spl beta/-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 /spl beta/-relaxations involving cooperative motions of methyl and ester groups in amorphous domains, to the /spl alpha/-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.