Ductility and Flame Retardancy Enhancement of PVC by Nanostructured Fly Ash

Fly ash (FA) obtained from a coal-fired local thermal power station was converted into a nanostructured material by mechano-chemical activation using a high energy planetary ball mill. Contact angle measurements and FTIR spectroscopy confirmed the surface modification of mechano-chemically activated FA (MCA-FA). Subsequently, a solution casting method was used to prepare poly(vinyl chloride) (PVC) matrix composites with varying amounts of fresh FA and MCA-FA. Mechanical testing results of the composites revealed that incorporation of fresh FA in PVC resulted in a higher tensile strength with brittle failure; addition of MCA-FA to PVC resulted in higher elongation at break values while retaining the ductility of the PVC. We have proposed a plausible mechanism explaining the influence of fresh FA and MCA-FA on the mechanical behavior of these composites. As fresh FA and MCA-FA contain basic oxide materials, they tend to improve the fire retardancy of PVC even at a very small loading. Overall, the nanostructured MCA-FA could find application as a filler in PVC-based products.