The Physical and Mechanical Properties of Biocomposite Films Composed of Poly(Lactic Acid) with Spent Coffee Grounds

Abstract

The aim of this research was to prepare and characterize biocomposite films from poly(lactic acid) (PLA) with spent coffee grounds (SCG). PLA can be derived from renewable resources. The SCG component consists of cellulose, hemicellulose and coffee oil 10.98%. SCG can simultaneously act as plasticizer and filler in the composites that can enhance the mixing process. The PLA/SCG biocomposite films were processed by a twin-screw extruder and blow film extruder. They were prepared by using various SCG concentrations (0%, 5%, 7.5% and 10% of SCG). The Scanning Electron Microscopy (SEM) results showed that the PLA matrix with SCG was miscible and had the SCG was well good distributed. Elongation at break was increased, when the amount of SCG was increased, with the results of PLA and PLA/SCG 10% being 5.07% and 6.63% respectively, while hardness, brittleness and tensile strength decreased. UV-vis spectrophotometric measurement of PLA/SCG biocomposite films showed a considerable reduction in transmission of all UV wavelengths (UV-A, -B and -C) and visible light with increasing SCG content. Hence, in this research, SCG can be used as filler in PLA films in order to produce biodegradable films and developed as agricultural film products. The PLA/SCG biocomposite films have shown good properties and are environmentally friendly.