Clay such as kaolinite, is commonly used as an additive to modify the thermal properties of polymer. In this paper, the morphology, composition, shape and structure of kaolinite was characterized by various advanced techniques. The TEM/ EDX data showed that the kaolinite had a larger particle size and a Si/Al ratio of 1.8. The individual particle of kaolinite was a single crystalline. TEM also showed that these particles were always stacked together due to the presence of electrostatic cohesive energy and hydrogen bond between plaletes. The PAS FTIR spectra showed that no absorbance of hydroxyl group for hydration water in hydrogen bond region or at 1650cm- 1 was observed at room temperature. It meant a little ability to adsorb water for kaolinite particle. Kaolinite clay also showed no change for its PAS FTIR spectra with increasing temperature. The TGA results revealed that kaolinite almost doesn′ t lose weight at 60℃ due to loss of dehydration of absorbed water, however, it will decomposed around 510℃ and lose its hydroxyl functional group in the form of water (dehydroxylation). The result is consistent with that of PAS FTIR analysis. This suggests that the structural hydroxyl group on the surface of individual kaolinite clay particle is very stable below 500℃ , and the kaolinite composed polymer could be got by the reaction of its stable structural hydroxyl group with isocynate group of polyurethane prepolymer.
