Robust and sustainable PBAT – Hemp residue biocomposites: Reactive extrusion compatibilization and fabrication

Polybutylene adipate-co-terephthalate (PBAT) is one of the most attractive biodegradable polymers that is touted to replace single-use plastics. In this research, hemp powder (HP), a byproduct of bast hemp fiber production process was investigated as a functional additive of PBAT resins to produce biocomposites. An industrially relevant, continuous, and scaleable extrusion process was employed to effectively disperse the HP in the PBAT. Maleic anhydride grafted PBAT (mPBAT) was produced through a peroxide-initiated reactive extrusion process and used as a functional additive of the PBAT-HP biocomposites. The effect of HP compositions (10–40 wt%) on the structure, processing, and thermo-mechanical properties of the biocomposites was investigated and reported. The mPBAT improved the interfacial interaction between the HP and PBAT that resulted in a homogeneous dispersion of the hemp particles in the PBAT matrix and a substantial increase in the tensile strength (209%), toughness (∼300%), impact resistance (∼90%), and other properties. Furthermore, the heat deflection temperature of biocomposites with 40% HP was found to be ∼60 °C higher than the pristine PBAT. Overall, the biocomposites displayed appealing material properties making it attractive for a range of single-use consumer goods, such as fast-food utensils, cosmetic containers, and food containers.