UV resistance and fire retardant property enhancement of unsaturated polyester composite

Polymer matrix composites are increasingly being used due to their low cost and simple fabrication methods. Polyester resins are amongst the most cost effective and efficient types of resins. But certain drawbacks limit the performance of these resins to be used as structural materials. These limitations include poor fire retardant properties, degradation on exposure to UV radiations and moisture diffusivity. To overcome these drawbacks, certain additives have been used such as aluminium trihydroxide (ATH) and carbon black. ATH serves the purpose of improving the fire retardant properties and carbon black provides UV resistance to the composite. In the present work, the effect of ATH and carbon black, to improve fire resistant properties and UV resistance of unsaturated polyester resin, has been investigated. An estimation of the limited oxygen index, smoke density rating and thermogravimetric analysis of ATH-filled resins has been carried out. Results indicate that the mechanical properties such as tensile strength and tensile modulus can be used to estimate the extent of degradation of carbon-filled resin on exposure to UV radiations. It has been found that even after UV exposure, the mechanical properties of carbon-filled samples do not decrease significantly. These tests have been performed at different loadings of the filler materials. Apart from the extent of loading, the amount of dispersion of the filler in the matrix is also found to influence the final properties of the polymer composite. The appropriate method of dispersion has been developed based on the observations made from the scanning electron microscope images.