Ultrafine fly ash as a reinforcing filler in poly(lactic acid) matrix

Fly ash, inexpensive and not eco-friendly material, is the residue from the coal burning in thermal power stations. If ways can be found to use it, it will facilitate applications for the ash materials and simultaneously reduce the pollution. In this study, silane-grafted ultrafine fly ash (S-UFA) was used as a reinforcing filler in poly(lactic acid) (PLA) to prepare a series of PLA/S-UFA composites. The tensile strength of PLA/S-UFA composites increases with the increase of S-UFA content when less than 20 wt %; after a loading fraction greater than 30 wt %, the tensile strength of the composites decreases with the increasing S-UFA weight fraction. The morphology of PLA/S-UFA composites was observed by scanning electron microscope (SEM). X-ray diffraction (XRD) analysis was applied to investigate the crystal structure of S-UFA and the composites. The thermal properties of these composites were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA results showed that the thermal stability of PLA/S-UFA composites slightly decreased with the increasing S-UFA loading fraction. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43716.