Abstract
Biopolymer blends consisting of insulating crystalline poly(3-hydroxybutyrate) (PHB)/Poly(propylene carbonate) (PPC)/multi-walled carbon nanotubes/plasticizer were prepared by solvent casting, then melted to form films with the hydraulic hot press. The miscibility, crystallization, morphology, thermal properties, and electrical properties were investigated by DSC, TGA, TEM, DC-and AC conductivity. The presence of MWCNT shows the important effect on dielectric and conductivity properties of PHB/PPC blends. The blend films show improved the electrical conductivity from 10(-17) Scm(-1) of the pure PHB film to 3 x 10(-1) Scm(-1) by increasing the concentration of MWCNTs for blend 4. The dielectric constant of (epsilon') of PHB blend has a maximum of between 40 and 200. It has increased similar to 50 orders than pure PHB and pure PPC. The activation energy for DC conduction is about 0.119-0.442 eV, which is typical of electronic conduction in blends 1, 2, and 3, it decreased with increasing the MWCNTs concentration in blend 4 and the conductivity believes like semiconductive behavior. TEM was found that the nanotubes are dispersed uniformly in the PHB matrix and the PHB chains wrap around the nanotube walls.