Development of polyvinyl chloride/waste rice husk ash/modified montmorillonite nanocomposite using epoxidized soybean oil as green additive substituting synthetic plasticizer and compatibiliser

The trend of replacing synthetic additives in polymer composite systems with more renewable additives has become necessary in order to improve the biodegradability of the composite and the sustainability of mankind. In this study, Epoxidized soybean oil (ESO) was employed as a green additive with waste Rice husk ash (RHA) and Organically modified montmorillonite (OMMT) used as a biofiller and nanofiller to obtain Polyvinylchloride (PVC)/RHA nanocomposite. Initially, ESO was successfully established as a green additive that served a dual function of both compatibilizer and plasticizer. The optimum amount of ESO was 7.5 phr to obtain the best-moulded composites. Later OMMT was introduced as a reinforcing nanofiller in the composite by keeping ESO constant at 7.5 phr. Among all variations, the composite with 1 phr OMMT showed the best properties. The interaction among the components was analysed by Fourier Transform Infrared Spectroscopy (FTIR) along with X-ray diffractometry (XRD). Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM) were applied to analyse the surface morphology of the nanocomposites. The thermal and mechanical properties were studied with a Thermogravimetric analyzer (TGA) and Universal Testing Machine (UTM). Introduction of 1 phr OMMT into the composites improved the tensile properties by 97%, flexural properties by 90% and the shore D value by 91%. The swelling percentages of acid, alkali, and water vapour resistance of nanocomposites with 1 phr OMMT after 168 h were 0.09, 0.11, and 0.35 respectively. The LOI values for flame retardancy improved considerably on addition of OMMT to the composites, rising from 55.5 to 66.6%.