A DIELECTRIC INVESTIGATION OF MISCIBILITY AND MORPHOLOGY IN ENGINEERING THERMOPLASTICS

Measurements of complex relative permittivity over extended ranges of frequency and temperature have been obtained for a number of commercia lly important engineering thermoplastics. The study provides evidence for partial miscibility of the component polymers of impact-modified p olycarbonate/polybutylene terephthalate and polycarbonate/polyethylene terephthalate blends and for a two-phase blend morphology with a poly ester-rich dispersed phase in a continuous matrix rich in polycarbonat e. A second representative conclusion concerns poly(acrylonitrile-buta diene-styrene) where dielectric spectroscopy yields separate absorptio ns which can be related to the miscibility and morphology of the indiv idual phases. In this case two low-temperature absorptions are attribu ted respectively to rubber-rich and styrene-acrylonitrile-rich regions in the core and shell of the latex particles which constitute the dis persed phase.