Structure, performance, and crystallization behavior of Turkey leonardite and raw kaolin added polylactic acid composite films

Abstract

Polylactic acid (PLA) film composites filled with two clays, Raw Kaolin (KAO), an inorganic structure, and Leonardite (LEO), an organic structure, as well as KAO/LEO mixtures, were prepared via solvent casting method. The main aim of this research was to investigate both the individual and the synergetic effects of LEO and KAO; they are incorporated together into a PLA matrix. The influence of these fillers content on the morphological and structural characteristics of the composites was investigated by the DSC, TGA, FT-IR, SEM, XRD, color, haze, and opacity analysis. According to the TGA analysis, significant decreases in Tmax2 were observed with the addition of LEO in PLA. It is also seen in films with KAO/LEO that support this result. Utilizing the solvent casting method, two melting points were formed in PLA films. The P0 film has lower Tg, Tcc, and Tm1 values than other films. However, there were small changes in Tg and Tm2 values in all films. Up to 7.5% amount of LEO and KAO, the mechanical properties of the films improved. The 3L film exhibited the best mechanical properties. The filler materials used were mostly homogeneously distributed, according to the SEM analysis, and as the amount increased, agglomerations were observed in the fillings on the surface. The addition of LEO and KAO changed the surface color, visual appearance, and opacity significantly. The haze values of films are near 100. These film composites have been shown to improve many properties of the P0 film. Graphical Abstract