The biocomposites properties of compounded poly(lactic acid) with untreated and treated spent coffee grounds

Abstract

AbstractPoly (lactic acid) (PLA) is a biodegradable and environmentally friendly material. And the spent coffee grounds (SCG) are huge waste all over the world. Therefore, the issue that how to convert the low‐value wastes SCG into more valuable products is attracting more research attention. In this work, we compounded PLA with SCG. Firstly, the efficiency of oil extraction from SCG was compared by different methods and solvents. Then, the biocomposites specimens of different SCG contents (0, 5, 10, and 15 wt%) were prepared by extrusion and injection molding. The effects of SCG particle size and content on the thermal and mechanical properties were investigated. Next, the effect of coupling agent (4,4‐methylene diphenyl diisocyanate [MDI]) on the biocomposites properties at 10 wt% SCG was examined by Field emission‐scanning electron microscope and Fourier transform infrared spectroscopy. The results show that the tensile strength and elongation at break of the PLA composites with the optimal contents are increased by about 50% and 120%, respectively, compared with untreated SCG.