Unique behavior of in-situ generated nanosilica particles on physico-mechanical properties of fluoroelastomer

Fluoroelastomer (FKM) rubber containing different weight percentage of in-situ generated nanosilica particles have been prepared by sol-gel method using tetraethoxysilane (TEOS) as precursor and n-butyl amine as catalyst. FKM rubber with precipitated silica particles have also been prepared to compare the effect of in-situ generated nanosilica particles and precipitated silica particles on the physico-mechanical properties of FKM rubber. It is interesting to note that the FKM rubber containing in-situ generated nanosilica particles display excellent tensile stress-strain properties, rheological properties and thermal properties in comparison to the FKM rubber containing precipitated silica particles. The better performance of the in-situ generated nanosilica particles has been attributed to the good dispersion of in-situ generated nanosilica particles in FKM rubber matrix when compared to the precipitated silica particles. The fourier transform infrared (FTIR) spectroscopy clearly confirms the existence of chemical interaction between the FKM rubber chains and the in-situ generated nanosilica particles which leads to the good dispersion of the nanosilica particles in the rubber matrix. Strain sweep studies confirm the presence of more rubber-filler interaction in FKM rubber filled with in-situ generated nanosilica particles. On the other hand, strain sweep studies confirm the presence of more filler-filler aggregation in FKM rubber filled with precipitated silica particles. The dispersion of the in-situ generated nanosilica particles and precipitated silica particles in the surface and bulk of FKM rubber has been studied by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Selected samples have been cured to understand the effect of curing on the efficiency of in-situ generated nanosilica particles and precipitated silica particles on the physico-mechanical properties of FKM rubber.