Electrical properties of conductive polymer composites prepared by an innovational method

 An innovational method that poly(styrene-co-maleic anhydride) (SMA), a compatibilizer of immiscible nylon6/polystyrene (PA6/PS) blends, was first reacted with carbon black (CB) and then blended with PA6/PS, has been employed to prepare the PA6/PS/(SMA-CB) composites of which CB localized at the interface. In PA6/PS/CB blends, CB was found to preferentially localize in the PA6 phase. However, in the PA6/PS/(SMA-CB) blends, it was found that CB particles can be induced by SMA to localize at the interface. The electrical porperties of PA6/PS/(SMA-CB) composites were investigated. The results showed that the composites exhibited distinct triple percolation behavior, i.e. the percolation is governed by the percolation of CB in SMA phase, the continuity of SMA-CB at the interface and the continuity of PA6/PS interface. The percolation threshold of PA6/PS/(SMA-CB) was only 0.15 wt%, which is much lower than that of PA6/PS/CB. Moreover, the PTC (positive temperature coefficient) intensity of PA6/PS/(SMA-CB) composites was stronger than that of PA6/PS/CB and the negative temperature coefficient (NTC) effect was eliminated. The electrical properties of PA6/PS/(SMA-CB) were explained in terms of its special interface morphology: SMA and CB localize at interphase to form the conductive pathways.