Preparation and thermal stability of fluoroalkyl end-capped vinyltrimethoxysilane oligomeric silica/poly(acrylonitrile-co-butadiene) nanocomposites—application to the separation of oil and water

Fluoroalkyl end-capped vinyltrimethoxysilane oligomeric silica nanocomposites-encapsulated poly(acrylonitrile-co-butadiene) (NBR) [R_F-(VM-SiO₂) _n -R_F/NBR] were prepared by the sol-gel reactions of the corresponding oligomer [R_F-(VM) _n -R_F] in the presence of NBR under alkaline conditions. Interestingly, it was demonstrated that these obtained fluorinated nanocomposites can afford no weight loss corresponding to the contents of NBR in the composites even after calcination at 800 °C. On the other hand, the nanocomposites, which were prepared under the cross-linking conditions at 150 °C for 30 min by using NBR containing zinc oxide and sulfur (S₈) as the cure activator and the cross-linker, respectively, were found to exhibit a clear weight loss corresponding to the contents of the NBR after calcination at 800 °C. The fluoroalkyl end-capped oligomeric silica nanocomposites-encapsulated the cross-linked NBR were applied to the surface modification of glass to supply the superoleophilic/superhydrophobic characteristic on the surface. The nanocomposites possessing such superoleophilic/superhydrophobic characteristic were applied to the packing material for the column chromatography to separate not only the mixture of oil and water but also the W/O emulsion. In contrast, the nanocomposites, which were prepared under no cross-linking conditions, were not applicable to the packing materials for the separation of these mixtures due to the oleophilic characteristic of the encapsulated NBR in the nanocomposite cores.