The strive for utilization of green fillers in polymer composite has increased focus on application of natural biomass-based fillers. Biochar has garnered a lot of attention as a filler material and has the potential to replace conventionally used inorganic mineral fillers. Biochar is a carbon rich product obtained from thermochemical conversion of biomass in nitrogen environment. In this review, current studies dealing with incorporation of biochar in polymer matrices as a reinforcement and conductive filler were addressed. Each study mentioned here is nuanced, while addressing the same goal of utilization of biochar as a filler. In this review paper, an in-depth analysis of biochar and its structure is presented. The paper explored the various methods employed in fabrication of the biocomposites. A thorough review on the effect of addition of biochar on the overall composite properties showed immense promise in improving the overall composite properties. An analysis of the possible knowledge gaps was also done, and improvements were suggested. Through this study we tried to present the status of application of biochar as a filler material and its potential future applications.

Sustainable manufacture caused shift in automotive manufacturing practices.Polymer-based composites make up almost 15% mass of the entire vehicle, most importantly the fuel system of the vehicle. Poor electrical conductivity of the polymer composites leads to electrostatic deposition, which can lead to issues. Carbon based synthetic fillers like carbon fiber and carbon nanotubes are attractive options to develop electrically conductive composites, owing to their excellent electrical and mechanical properties. However, the production process of these reinforcements is highly time and energy intensive making it quite expensive and not quite sustainable. Lignocellulosic feedstock can be carbonized at a high treatment temperature of ≥1000 C to produce electrically conductive biocarbon filler. In this study biocarbon fibers developed using Douglas fir pulp, were incorporated into polyamide 12 matrix to develop composites. The composites were fabricated using hot compression mounting. At a filler loading of 7.5 wt% the composites reported log electrical conductivity value of À6.67 S/cm and at 35 wt% filler loading rate the composite conductivity was À0.31 S/cm. An electrical conductivity of À8.70 S/cm for polyamide 6 composites filled with 20 wt% carbon fiber and À1.03 S/cm were reported for 40 wt% carbon fiber concentration in reviewed literature. The electrical conductivity values for the samples with 20 and 40 wt% carbon fibers are significantly lower compared to the biochar fiber filled composites at 25 and 35 wt% biochar filler loading rates, indicating the effectiveness of the biochar filler as a conductive filler in developing electrically conductive, sustainable composites.