Influence of Non-Activated and Activated Biochar on Properties of Flexible Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) Bioplastic

In this work, flexible poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) (PLA-PEG-PLA) composites incorporated with non-activated coconut-shell biochar (BC) and activated coconut-shell biochar (ABC) were successfully prepared through melt blending. Scanning electron microscopy (SEM) indicates that all the composites showed good phase compatibility, suggesting strong interfacial adhesion between the PLA-PEG-PLA matrix and both the biochar types. Differential scanning calorimetry (DSC) demonstrated that the composites containing 0.5 wt % biochar exhibited the highest crystallinity for both BC and ABC. When the biochar content exceeded 0.5 wt %, the effectiveness of biochar as a nucleating agent diminished due to the restriction of chain mobility in PLA-PEG-PLA. Thermal stability from thermogravimetric analysis (TGA) and mechanical properties from tensile tests of the composites were improved by the addition of these biochars. The 0.5 wt % biochar yielded the highest maximum tensile strength and Young’s modulus values of the composites. The DSC, TGA, and tensile results indicate that BC has a high potential to be used as nucleating, thermal stabilizing, and reinforcing agents for PLA-PEG-PLA compared to the ABC.