Enhanced thermal properties of sepiolite/poly-3-hydroxyoctanoate nanocomposites as biodegradable packaging materials

Abstract

In this study, sepiolite was studied as a nanofiller to develop biodegradable packaging materials. Phenyl triethoxy silane (PTES) was grafted onto pristine sepiolite to prepare PTES grafted sepiolite (PSP). The nanocomposites comprising of poly-3-hydoxyoctanoate (PHO) and PSP were fabricated via the melt-blending method and were exposed to different doses (10 and 25 kGy) of gamma irradiation. The scanning electron micrographs of gamma-irradiated nanocomposites demonstrated nice network formation between the polymer matrix and sepiolite nanofibers due to a compatibilizing effect of PTES. The thermal properties of the resulting nanocomposites were enhanced as compared to pure polymer. The gel content of nanocomposites was increased with a high dose of gamma-irradiation. The irradiated nanocomposites buried in soil revealed significant weight loss along with agglomerates formation. Fourier transform infrared analysis of gamma-irradiated nanocomposite sheet buried in soil for three months demonstrated a considerable reduction in the intensities of absorption peaks at 1730 cm-1 (carbonyl stretching), 1385 cm-1 (C-CH3 bending vibration), and 1150 cm-1 (C-O-C linkages). Thus, the gamma-irradiated nanocomposites may be a good substitute for synthetic plastics in food packaging applications.