The effect of bio-carbon addition on the electrical, mechanical, and thermal properties of polyvinyl alcohol/biochar composites

The composites of polyvinyl alcohol and bio-carbon (i.e. biochar) were prepared by a solution casting method to investigate their electrical conductivity and mechanical and thermal properties. The polyvinyl alcohol/biochar composites filled with 2wt% and 10wt% biochar exhibit a similar electrical conductivity to most carbon nanotube and graphene reinforced polyvinyl alcohol composites. Results of mechanical tests indicate that addition of the biochar reduced the tensile strength of the polyvinyl alcohol/biochar composites. However, the tensile modulus and storage modulus above the glass transition temperature were improved through the addition of biochar. The results of thermal gravimetric analysis and differential scanning calorimetry indicated that addition of biochar increased the thermal decomposition temperature of polyvinyl alcohol/biochar composites. These results demonstrate that biochar holds great potential for replacing the carbon nanotubes and graphene as a filler of polymers in electrical applications.