Erosion resistance of alumina-filled silicone rubber nanocomposites

This paper deals with the experimental studies on the erosion resistance of low weight % alumina-filled nanocomposites and highly filled microcomposites. Erosion resistances of 2.5 % and 4 % by weight alumina-filled silicone rubber nanocomposites and 5 %, 10 %, 15 %, 20 % and 30 % by weight ATH filled microcomposites have been compared. For the performance comparison, inclined plane tracking and erosion resistance tests have been done on the silicone rubber samples. The results obtained indicate that the performance of 4 % by weight nanocomposite is comparable to that of the 30 % by weight ATH composite. Thermo gravimetric analysis shows that the thermal stability of the nanocomposite is better than the microcomposite even at low concentration of the nanofillers studied. The above encouraging results can be mainly attributed to the better thermal stability of the nanocomposite due to the large increase in the number of nanofillers, significant quantity of polymer chains with restricted mobility at the interface between the polymer and the fillers and better physical bonding between the nanofillers and the polymer matrix. Interestingly, formation of entirely different types of physical micro structures, viz., lump type and honey comb type have been observed at the degraded portions of the microcomposites and the nanocomposites respectively which also supports the above observation. It is also noticed that the ratio of r.m.s to average leakage current is a reflection of the degree of erosion of the sample which in turn seems to be a good indicator to assess the degradation performance of materials.