Abstract:In recent years, low-cost carbons derived from recycled materials have been gaining attention for their potentials as filler in composites and in other applications. The electrical and mechanical properties of polymer composites can be tuned using different percentages and different kind of fillers: either low-cost (e.g., carbon black), ecofriendly (e.g., biochar), or sophisticated (e.g., carbon nanotubes). In this work, the mechanical and electrical behavior of composites with biochar and multiwall carbon nanotubes dispersed in epoxy resin are compared. Superior mechanical properties (ultimate tensile strength, strain at break) were noticed at low heat-treated biochar (concentrations 2-4 wt %). Furthermore, dielectric properties in the microwave range comparable to low carbon nanotubes loadings can be achieved by employing larger but manageable amounts of biochar (20 wt %), rending the production of composites for structural and functional application cost-effective.

This study reports about the use of Biochar derived from maple tree as a filler in Epoxy resin. Maple tree blocks were pyrolyzed in inert atmosphere at 600 °C and 1000 °C respectively and were characterized morphologically. The composite mechanical properties, i.e. stress-strain curves and related parameters (ultimate tensile strength, Young modulus, resilience, tensile toughness) were recorded as well as their friction coefficient. It is shown that at very low wt.% of the filler, the Young modulus is increased while at higher wt.% (2 wt% and above) the fragile behavior of the resin was converted in a ductile one, as elongation at break increased from 0.02 to 0.12. A huge impact of the filler is observed on tensile toughness as for the best sample is increased 11 times with respect with pure resin. A simple model able to describe the results and make predictions on other wt.% is presented as well.

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