Sepiolite / poly-3-hydroxyoctanoate nanocomposites: Effect of clay content on physical and biodegradation properties

Vinlytrimethoxy silane (VTMS) was grafted onto the pristine sepiolite. This VTMS containing sepiolite (VTMS-g-Sep) was used to prepare sepiolite/poly-3-hydroxyoctanoate (Sep/PHO) nanocomposites sheets by melt blending technique. Fourier transform infrared (FTIR) spectroscopy showed the formation of siloxane linkages in nanocomposites. Wide angle x-ray diffraction analysis indicated the formation of new crystal in nanocomposites. Thermal analysis demonstrated an increase in melting temperature of nanocomposite sheets. An increase of 1.4 and 16 folds in tensile strength and elongation at break of Sep/PHO nanocomposites was observed in comparison to PHO alone. The degradation studies of Sep/PHO nanocomposite were carried out both under in-vitro conditions and soil. Scanning electron microscopy showed the formation of agglomerates, grooves, and pits on the surface of Sep/PHO nanocomposite sheets buried in soil. FTIR analysis of the Sep/PHO nanocomposite sheets buried in soil showed a decrease in the intensities of the characteristic absorption bands at 2948 cm(-1) (antisymmetric stretching vibrations of the C-H bonds) and 1730 cm(-1) (carbonyl C-O stretching vibration). While, intensities of absorption bands at 3670-3070 cm (-1) (OH stretching vibrations) and 1050-1150 cm(-1) (C-O bending vibration) were increased after 90 days of soil burial.