Synergistic effect of carbon nanoparticles on the mechanical and thermal properties of poly(lactic acid) as promising systems for packaging

Abstract

Due to the high demand of the use of food packaging in the present day, the waste from the material disposal has become a problem of high environmental impact. In this perspective, biodegradable polymers can represent a viable alternative as they degrade after their disposal, thus reducing their environmental impact. The poly(lactic acid) or polylactide is a biodegradable, biocompatible, and compostable polymer, being considered by many authors as one of the most promising biopolymers in industrial applications. However, its low thermal and mechanical properties make it an unfeasible option to replace synthetic polymers. Consequently, polymer nanocomposites containing carbon nanoparticles are products of relevant interest currently, mainly due to the thermal, mechanical, electrical, and optical properties these materials can present. Therefore, carbon nanoparticles (carbon nanotubes, graphene, and fullerene) modified with octadecylamine in their isolated state and in ternary systems in concentrations of 0.01%, 0.03%, and 0.09% were obtained from poly(lactic acid) polymer nanocomposites. After obtaining them, these systems were analyzed by TGA, DSC, FTIR, XRD, SEM, DMA, and NMR techniques. The presence of the octadecylamine modified carbon nanoparticles was able to increase the thermal and mechanical resistance of the poly(lactic acid) matrix. The systems with 0.03% of the nanostructures showed better results in both analyses. In the system with 0.09%, agglomeration occurred, and in ternary systems, the application of these particles results in a greater impact on the molecular mobility exhibiting a synergistic effect that may come from a better dispersion.