Mechanical and thermal properties of unsaturated polyester/calcium carbonate nanocomposites

In this study, the nano-sized calcium carbonate (CaCO3) is synthesized using an in situ deposition technique and characterized using TEM. The particle size is found to be around 50-60 nm. Nanocomposites of UPR and nano-CaCO3 particles are prepared by casting technique. The TEM study demonstrates that nano-CaCO3 particles are dispersed in a UPR matrix uniformly and few agglomerations are found at and above 5 wt% of nano-CaCO3 in the UPR matrix. XRD studies reveal the formation of nanocomposites. The mechanical and thermal properties of UPR/CaCO3 nanocomposites are better than those of pure UPR. Up to 5 wt% loading of nano-CaCO3 in the UPR matrix, the tensile, flexural, and impact strengths slightly improved. The flexural modulus increases with increase in nano-CaCO3 concentration. The morphology of the impact fracture surface of nanocomposites is analyzed by means of SEM. The dynamic mechanical analysis of the nanocomposites clearly indicates a progressive increase in T-g with the progressive addition of nano-CaCO3 till a loading of 5 wt% of nano-CaCO3 in the unsaturated polyester resin.