Mechanical and dielectric properties of SEBS modified by graphite inclusion and composite interface

What is it about?

Tough and flexible dielectrics were prepared using graphite (G), a natural and low-cost resource, as filler in polystyrene-b-(ethylene-co-butylene)-b-polystyrene (SEBS) and maleinized SEBS (SEBS-MA) matrices. The disintegration of graphite in submicron particles was accomplished by the shear forces during the melt processing step and it was highlighted by atomic force microscopy. Simultaneous increase of tensile strain, strength and Young’s modulus was noticed for SEBS/G and SEBS-MA/G composites compared to unfilled matrices, this remarkable feature being previously reported only for some nanocomposites. Moreover, an exponential variation of the dielectric permittivity with the volume fraction of G was obtained. Higher reinforcing efficiency and better dielectric properties were observed in SEBS-MA/G composites, compared to the corresponding SEBS/G composites, due to the stronger polymer-filler interface and better dispersion of graphite. This study brings new insights into nanolevel properties of SEBS composites and it opens new perspectives on high performance composites by using graphite instead of expensive graphene and efficient melt mixing process.

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Why is it important?

Our study aimed to develop a new strategy to prepare high performance easily scalable composite materials using graphite as low-cost filler, instead of expensive graphene in block copolymer elastomers. The disintegration of graphite in submicron particles due to the shear forces during the melt processing step and some exfoliation of graphite made these composites to have a behavior close to that of nanocomposites: these composites show simultaneous increase of tensile strain, strength and Young’s modulus, compared to pure matrices. Our study highlights the possibility of preparing low-cost SEBS/graphite composites with improved mechanical behavior, showing low dielectric loss in a wide range of frequency.