Compatibilization of toughened polypropylene/biocarbon biocomposites: A full factorial design optimization of mechanical properties

The structure-property relationships of toughened polypropylene/biocarbon biocomposites prepared via melt extrusion are investigated with a focus on the effects of biocarbon particle size, functional polymer type and concentration. A full factorial design was utilized to study each factor's main effect and how their interactions with other factors affect the final mechanical properties of the biocomposites. The statistical analysis confirmed the synergistic interactions between the biocarbon and the functional polymer which improves the impact toughness of the composites by 120% while maintaining or improving the stiffness of the composite. Among the investigated factors, the type of functional polymers had the greatest impact on the properties by affecting the morphology of phases. Based on these analyses, the biocarbon with particle size range of 106-125 μm together with 5.0 wt% of maleic anhydride grafted polypropylene was selected as the optimum composite formulation providing the best stiffness-toughness balance among the tested samples.