A novel two-step melt blending method to prepare nano-silanized-silica reinforced crosslinked polyethylene (XLPE) nanocomposites

In the current study, nano-silanized silica-filled crosslinked polyethylene (XLPE) nanocomposites were prepared by a novel two-step melt blending technique. Nano-silanized silica was used as a filler and dicumyl peroxide was used as a crosslinker. Crosslinking was introduced in the base polymer by adding 0.2% dicumyl peroxide in second step in order to avoid premature crosslinking. The effect of nano-silanized silica on XLPE nanocomposites was investigated. FTIR analysis was carried out to detect the degree of crosslinking in the composite. The effect of nano-silanized silica on the UV degradation behavior was also assessed. The extent of crosslinking was also estimated by density measurement and solvent swelling method. Thermal behavior was studied by thermogravimetric analysis and differential scanning calorimetry. Dielectric breakdown strength was studied in the frame of Weibull distribution method. The flammability of nano-silanized silica-filled crosslinked nanocomposites was studied by both vertical and horizontal flame test methods to quantify flammability rating and rate of burning, respectively. SEM analysis was carried out to explain the morphology of polyethylene after crosslinking and dispersion and distribution of filler within the polymer matrix. It was shown that 2 phr addition of nano-silanized silica improved the performance of XLPE composites.