Study of Thermal Stability of Polyurethane-Silica Composite and Nanocomposite with Approach of Rocket Solid Propellant

One way to thermal stability and ablation improving of polyurethane elastomers with approach of solid propellant rocket insulation, is use of fillers such as silica particles with property of high ablation. In this study, it was paid to prepare polyurethane-silica composites (16,25 and 38% by weight) and polyurethane-silica nanocomposites (10, 16 and 25% by weight) and then interaction, morphology and thermal stability of them has been investigated by using of Fourier transform infrared spectroscopy (FTIR & ATR), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). Infrared spectra are confirm the formation of polyurethane and SEM images also show the proper distribution of the silica particles in the matris of polyurethane. TGA results also show that the temprature of 50 percent weight loss, due to function of silica particles as char trap, is increased that this result was approved by using of corrected thermal gravimetry method. The amount of residual mass of polyurethane composite containing 25 wt% silica was about 0.72 wt.% while this amount for the nanocomposite with the same amount of silica particles was equal to 1.8 wt.%.