DIELECTRIC-PROPERTIES OF POLY(3-HYDROXYBUTYRATE) GELS IN DIMETHYLFORMAMIDE

The thermal and dielectric properties of poly(3-hydroxybutyrate) in di methylformamide at a concentration of 10 gl(-1) have been investigated . This system shows a gel-sol transition as the temperature is raised from 25 to 90 degrees C. Two endothermic peaks are revealed by differe ntial scanning calorimetry at 70 and at 85 degrees C respectively, whi ch pair with two discontinuities in the electrical conductivity and in the permittivity when the sample undergoes annealing. A description o f the observed process in terms of melting of microcrystalline domains is presented. Copyright (C) 1996 Elsevier Science Ltd.