Carbon black filled PET/PMMA blends: Electrical and morphological studies

In this work, the electrical and morphological properties of blends of poly (ethylene terephthalate) (PET), poly(methyl methacrylate) (PMMA), and carbo n black (CB) were analyzed. Resistivity decreases similarly in both PET and PMMA with CB concentration. Similarly in the PET/PMMA blend, extensive mod ification to this behavior occurs, since resistivity becomes a function of morphology and specific location of CB in the polymers. A minimum in the re sistivity of the blend with 5% CB (PET basis) is observed at 100% PET, wher eas with an increase in the CB content to 20%, the minimum in the resistivi ty shifts to 60% PET. High conductivity is observed when PET is the continu ous phase (having the larger viscosity). Large stresses lead to a large dis persion of CB and a high deformation and rupture of the dispersed PMMA phas e. This situation itself promotes an increase of surface area of droplets a nd high CB concentrations at the interface. Consideration is given to model s that predict a selective location of conductive particles in the PET matr ix based on its lower interfacial tension with CB.