Rheological behaviors and electrical conductivity of long-chain branched polypropylene/carbon black composites with different methods

The isotactic polypropylene/carbon black (iPP/CB) and the long-chain branched polypropylene/carbon black (LCBPP/CB) composite melts with the melt blending method and the solution process were chosen in this paper to know the relationship between rheological and electrical percolation process and learn the evolution and the destruction of rheological network. The more rheological percolation threshold than electrical percolation threshold in iPP/CB composites and the less rheological percolation threshold than electrical percolation threshold in LCBPP/CB composites are mainly attributed to the two kinds of mechanisms governing the electrical network and the rheological network. The agglomeration of CB particles which is accelerated by annealing at elevated temperatures promotes the self-perfection of rheological network. The strong interaction between the polar long-chain branched structure and filler also led to the reduced tp. The network of LCBPP/CB composites is more difficult to be broken than the network of iPP/CB composites with the solution process.