Biodegradability studies of poly(butylene succinate)/organo-montmorillonite nanocomposites under controlled compost soil conditions: Effects of clay loading and compatibiliser

Biodegradable nanocomposites were prepared from poly(butylene succinate) (PBS) and organo-montmorillonite (OMMT), in the presence of maleic anhydride-grafted PBS (PBS-g-MA) as compatibiliser. The effects of OMMT loading and PBS-g-MA on the biodegradability of PBS nanocomposites were investigated. Soil burial testing was carried out for 180 days in natural organic humus compost soil under controlled conditions. It is noted that the weight loss of nanocomposites was lower than that of neat PBS, due to the enhanced barrier properties after addition of OMMT. However, the addition of PBS-g-MA increased the weight loss of nanocomposite. The mechanical properties of PBS nanocomposites were significantly reduced after the soil burial. Biodegradation of the material was further confirmed by the decreased molecular weight through gel permeation chromatography (GPC), and changes in the chemical structure as verified by Fourier transform infrared (FTIR) spectroscopy. This was supported by the degraded surface of PBS and the nanocomposites observed under scanning electron microscopy (SEM). The effects of biodegradation on the thermal properties were studied through the differential scanning calorimetry (DSC). In addition, the biodegradation rate of the materials was determined by measuring the carbon dioxide (CO2) evolution. The degraded samples were recovered and PBS-degrading bacteria were found to be present in the exposed samples.