Thermo-Mechanical Properties of LDPE/SiO2 Nanocomposites based on Chemically Functionalized SiO2 Nanoparticles

Due to its excellency as electrical insulating materials, low density polyethylene, LDPE, must have improved thermal and mechanical properties to tolerate the worst conditions when used in high-voltage insulation systems. One approach is the incorporation of suitable nanoparticles particularly those with a modified surface to meet the chemistry of LDPE matrix. Thus, LDPE/SiO2 nanocomposites were synthesized using solvent cast method in which different loading of functionalized and un-functionalized SiO2 nanoparticles were mixed with the molten LDPE in presence of para-xylene as a solvent. The functionalization was performed using vinyl silane as a coupling agent. Thermal gravimetric analysis, TGA, was conducted over the temperature range of 25-600 degrees C. The same instrument was also used to perform differential scanning calorimetry (DSC) test. For all samples, the temperature that corresponds to 10% mass loss were extracted. Beside the TGA, dynamic mechanical analysis (DMA) was also performed using Triton Technology dynamic mechanical analyzer in its bending mode. In this test, rectangular samples were heated by 5 degrees C/min from room temperature to 100 degrees C at 1.0 Hz frequency. For the selected temperature range, the effects of incorporating SiO2 nanoparticles, either functionalized or un-functionalized, on storage modulus, loss modulus, and mechanical loss coefficient of LDPE/SiO2 nanocomposites are investigated.