Preparation and thermo-mechanical properties of heat-resistant epoxy/silica hybrid materials

Diglycidyl ether of bisphenol-A (DGEBA) based epoxy/silica hybrid materials filled with various amounts of 3-glycidoxypropyltrimethoxysilane (GPTMS) and silica nanoparticles were prepared, using 4,4'-diaminodiphenyl sulfone (DDS) as curing agent. The obtained hybrid materials were analyzed by means of Fourier-transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results indicated that the introduction of GPTMS and silica nanoparticles had synergistic effect. The addition of GPTMS not only ameliorated the compatibility between silica and the epoxy matrix but also increased the crosslinking density of the epoxy system; meanwhile the nano-silica further reinforced the inorganic network of the hybrid system. Consequently, the hybrid materials showed much improved heat-resistant properties. The storage modulus of the hybrid systems showed no obvious decrement in the glass transition region and kept at a high value even in the temperature region up to 300 degrees C. The integral thermal stability of the resulting hybrid materials was also improved compared with the corresponding pure epoxy resin.