Nanocomposites based on MWCNT and styrene-butadiene-styrene block copolymers: Effect of the preparation method on dispersion and polymer-filler interactions

Composites of Kraton-D® 1102 BT (a styrene-butadiene-styrene block copolymer) and multi-walled carbon nanotubes (MWCNTs) were prepared by melt mixing. The composites were characterized by electrical conductivity measurements (Coleman's method), mechanical properties (DMA and stress-strain tests), thermal stability (thermogravimetry) and morphology of dispersion (SEM). Finally, the resulting composites were compared with those made by the solution casting method. The results showed a strong influence of the preparation methodology on the final properties of the composites due to changes in morphology. Composites prepared by casting showed a higher electrical conductivity than extruded ones; the composites with 6 wt.% of MWCNT prepared by extrusion presented conductivity of the same order of magnitude as the composite with 1 wt.% of MWCNT prepared by casting - 10−3 to 10−4 S cm−1. However, the extruded samples presented better mechanical properties than the casting ones.