Design of graphene based conductive blends

Abstract

In this work, the effect of graphene platelet size on the electrical and rheological behavior of pure polymers and co-continuous blends was evaluated. Graphene presenting a surface area of 750 m2/g and a surface area of 50-80 m2/g was added in concentrations varying from 1 to 10 weight% to polymethylmethacrylate (PMMA), polystyrene (PS) and 50/50 PMMA/PS blend. The materials were obtained by twin screw extruder. The blends were further annealed at 200oC for 30 minutes, 1 hour and 2 hours under a pressure of 0.8 MPa in the hydraulic press. The morphology and electrical properties of the material prior and after annealing were evaluated by scanning electron microscopy and by broadband dielectric spectroscopy. It was shown that PMMA presented a lower percolation threshold than PS and that using a blend could reduce the percolation threshold. It was also shown that using blends is an interesting method to reduce the percolation threshold. Furthermore, the results indicated that the percolation threshold was lower for blends filled with graphene nanoplatelets having a larger surface area. It was also shown that graphene nanoplatelets having high surface area migrate faster towards the more favorable phase than the graphene nanoplatelets having lower surface area thus affecting the electrical and rheological properties. The size of graphene nanoplatelets affect the redistribution of the graphene nanoplatelets in the formation of co continuous network and strength of the blend matrix.

Date	19 Jan 2021
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Nicole R. Demarquette (Supervisor)