Design of sandwich structure conductive polypropylene/styrene-butadiene-styrene triblock copolymer/carbon black composites with inherent morphological tunability

The insulator-conductor transition of conductive polymer composites (CPCs) can be ascribed to the fabrication of conductive networks, and the morphology of conductive networks plays a significant role in the electrical conductivity. This study presents CPCs with inherent morphology tunability which can be controlled by kinetic methods (i.e., mixing procedures and sequences, and polymer melt viscosity). Polypropylene (PP)/styrene-butadiene-styrene block copolymer (SBS) (50/50, in volume)/10 phr (parts per hundred of the polymer matrix) conductive carbon black (CB) composites prepared by different compounding sequences (PP/CB composites mixed with SBS, SBS/CB composites mixed with PP, and PP/SBS blend mixed with CB) are named as PC₁₀S, SC₁₀P, and PSC₁₀. With the difference between the phase morphologies, distribution, and dispersion of CB, the PP/SBS/CB composites realize seven orders of magnitude difference in resistivity. The volume resistivity (ρ_v) of PC₁₀S SC₁₀P and PSC₁₀ are 1.57 × 10¹, 1.68 × 10², and 4.88 × 10⁸ Ω m, respectively.