Characterization of carbon black-filled immiscible polypropylene/polystyrene blends

The electrical and rheological behaviors of carbon black (CB)-filled immiscible polypropylene (PP)/polystyrene (PS) blends were investigated. The compounding sequence influences the phase morphology of the ternary CB/PP/PS composites and the distribution of CB aggregates. Simultaneous measurements of resistance and dynamic modulus were carried out to monitor the phase coalescence of the ternary composites and CB migration and agglomeration in the PS phase during annealing at temperatures above the melting point of PP. The variation of resistivity is mainly attributed to CB agglomeration in the PS phase and the interfacial region, while the variation of dynamic modulus is regarded as the superimposition of the phase coalescence and CB agglomeration in the PS phase. The ternary composites with themajority of CB particles distributed in the interfacial region show the lowest conductive percolation threshold and the most stable resistivity-temperature performance during heating-cooling cycles. (C) 2011 Society of Chemical Industry