Silanizing nano SiO2 and its application in recycled nitrile rubber to prepare super oil resistant/superhydrophobic/superoleophilic oil/water separator

Polymer wastes and oil slicks are environmental threats in the present century. Accordingly, the reuse of polymer wastes to absorb oil slicks could be an interesting topic. In this research, devulcanized nitrile rubber (DNBR) as oil resistant/recycled material were used to prepare an environmental friendly superhydrophobic/superoleophilic oil sorbent. For this purpose, silica nanoparticles were silanized using vinyltriethoxysilane. HR-TEM, FTIR and XPS analysis were performed to characterize the surface morphology and chemical composition of the pure and silanized nanoparticles. The grafted nano silica illustrated superhydrophobic behavior due to water droplet contact angle which was 156 compared to 53° for pure nano silica. XPS analysis showed that the content of Si, O and C elements on the surface of modified nano silica increased by 18%, 8% and 25%, respectively, compared to pure nano silica. The chemo-thermo-mechanical properties of the DNBR nanocomposites contained 6 phr of pure and silanized nanoparticles were evaluated. Results confirmed improvement in the curing and mechanical performances of the rubbery nanocomposite due to silane grafting. The modified nanocomposite had the highest oil absorption capacity over 2.4 g.g− 1 (i.e. for dense sheet). It efficiently separated about 91% of Persian Gulf oil/water mixtures with remarkable reusability of about 700 cycles.