Effect of surface-modified silica on the thermal and mechanical behaviors of poly(lactic acid) and chemically crosslinked poly(lactic acid) composites

This work studied the properties of poly(lactic acid) (PLA) and chemically crosslinked poly(lactic acid) (CrPLA) in the presence of different types of silica (SiO2): SiO2 from rice husk ash (RhSiO2) and commercially available SiO2 (CoSiO2). A mixture of triallyl isocyanate and dicumyl peroxide was used as a chemical crosslinking agent. The rice husk was burnt in a furnace to extract RhSiO2. The thermal and mechanical properties of the PLA and CrPLA composites were investigated as a function of the SiO2 content. The presence of C–H functional groups supports the compatibility of stearic acid and RhSiO2, thereby facilitating the esterification reaction observed in the Fourier transform infrared-attenuated total reflectance spectra. This played an important role in changing the properties of the PLA-based composites. The concave fracture surfaces were consistent with the tensile results, the thermal properties, and the degree of swelling, which suggested that there was a better reaction between stearic acid and RhSiO2. However, the heat deflection temperatures of both the PLA and the CrPLA composites were not significantly affected by blending with either CoSiO2 or RhSiO2.