Enhanced dielectric properties and positive temperature coefficient effect in the binary polymer composites with surface modified carbon black

We report a new kind of binary polymer [polypropylene (PP) and polyvinylidene fluoride (PVDF)] matrix composite containing surface modified carbon black (CB) by employing titanate coupling agent (NDZ-102) and silane coupling agent (KH550). Significant enhancement of dielectric properties ( conductivity and permittivity) and positive temperature coefficient effect (PTC) were observed in the CB-PP/PVDF composites when the concentration of CB reaches a critical value. These could be attributed mainly to the bridge-linked role of coupling agents between the CB and the binary polymer, which also improve the CB dispersion in the composites. Compared with KH550, NDZ-102 can form a flexile and thin interface layer, inducing a more effective increase in conductivity of the composites. Additionally, the composite with NDZ-102 modified CB displays excellent PTC stability.