Preparation of Superhydrophobic/Superoleophilic nitrile rubber (NBR) nanocomposites contained silanized nano silica for efficient oil/water separation

Nowadays, the superhydrophobic/superoleophilic nanocomposites has attracted considerable interests due to their unbeatable properties for oil–water separation. In this research, nitrile rubber (NBR) was used as oil sorbent due to its high elasticity under stresses and high resistance to organic solvents and fuels. To increase its oil absorption capacity, silica nanoparticles were silanized by vinyltriethoxysilane (VTES) at suitable silane concentration and added to a NBR compound. The surface modified nanoparticles were characterized by TGA, FTIR, XPS, SEM-EDX and XRD analysis as well as contact angle test to assess successful grafting of silane to the nanoparticles surface. The effects of nanoparticles on contact angle, oil absorption capacity, oil recovery efficiency of NBR samples was also studied. It was found that silanized nano silica caused considerable increment in the contact angle from 41 and 89.8° (i.e. for pure nano silica containing and pristine NBR samples, respectively) to 153°. It was specified that the nanocomposite increased oil absorption capacity of NBR up to four times. It was also found that the rubbery nanocomposite contained surface modified SiO2 nanoparticles retained 95% of oil recovery efficiency even after 1000 oil absorption/desorption cycles. The mechanical and dynamic mechanical properties of NBR compounds were also evaluated. The modified silica nanoparticles improved the thermomechanical properties of nitrile rubber and developed a high performance superhydrophobic/superoleophilic elastomeric material for oil/water separation.