Effects of tomato peel extract on morphological, chemical, thermal, and mechanical properties of poly(lactic acid)

Poly(lactic acid) (PLA) is a sustainable, biodegradable polymer with high brittleness, elastic modulus, poor ductility, and low tensile strain that might restrict the packaging applications. The properties of PLA can be modified by addition of various materials. This study intended to reveal the effect of PLA with various concentrations of tomato peel extract (TPE) on the morphological, structural, thermal, and mechanical properties of PLA/TPE biocomposites. TPE was incorporated into the PLA matrix at 2, 4, and 6% w/w. The morphological analysis showed that films were successfully prepared by a combination of solvent-casting and compression-molding. TPE was well dispersed at low concentrations, though at higher concentrations above 2% w/w, an agglomeration of the TPE was observed. Thermal analysis revealed that the glass transition temperature of the biocomposites decreased with increasing content of TPE. FTIR spectra of the biocomposites showed that several components of TPE, such as phenolic compounds and fatty acid esters, could be incorporated into the matrix. Better mechanical performance was obtained for 2 and 4% w/w of TPE content in terms of tensile strain (between 2.4 and 38% higher compared to neat PLA) that was an indication of higher mechanical flexibility. These results showed the application performance of TPE in packaging materials. Graphical abstract