Dielectric relaxation and compatibility investigation of polystyrene/polyvinyl chloride blends

A systematic dielectric study over a frequency range 100 Hz up to 100 kHz was carried out on polystyrene/polyvinyl chloride (PS/PVC) blends with different concentrations of maleic anhydride (MA) ranging from 0-20%. After subtraction of the losses resulting from DC conductivity, the dielectric data were fitted in the frequency domain by two Frohlich regions. The first absorption region in the lower frequency range, which is found to be unchanged by increasing either blend ratio or the content of maleic anhydride, could be ascribed to the Maxwell Wagner effect because of the difference in the permittivities and conductivities in polymeric materials. The relaxation time associated with the second absorption region, which involve the rotation of various segments of the side group, is found to increase by increasing both the PS and MA content in the blend. The compatibility study undertaken by using either dielectric or viscosity techniques led to the conclusion that PS/PVC blends free from MA and those containing 5% MA are incompatible. On the other hand, the addition of MA with concentration 10% and 20% could solve to some extent the problem of phase separation (i.e., improve the compatibility of PS/PVC blends).