The heat resistance of a polyurethane coating filled with modified nano-CaCO₃

The modification of polyurethane coating by adding surface-modified CaCO₃ nanoparticles (nano-CaCO₃) was investigated in this paper. To improve interfacial interaction between the nano-CaCO₃ and the polyurethane (PU) matrix, a silane coupling agent (KH560) was used to modify the nano-CaCO₃. The grafting of KH560 on the nano-CaCO₃ surfaces was characterized by the TEM, FTIR and TGA techniques. The modification of the nano-CaCO₃ surfaces with KH560 was demonstrated to improve the dispersity of nano-CaCO₃. FTIR, SEM and AFM were used to characterize the polyurethane coating. The FTIR spectrum indicated that the modification of nano-CaCO₃ does not influence the chemical structure of the PU matrix. The roughness and gloss of the nanocomposite coatings containing various amount of nano-CaCO₃ were evaluated using a roughness tester and a brightness meter. The heat resistance of the polyurethane coating containing various amounts of nano-CaCO₃ was evaluated using the TGA technique. The results revealed that nano-CaCO₃ treatment with KH560 improves the nanoparticle dispersion and heat-resistance of polyurethane coating.