Polyhedral Oligomeric Silsesquioxane (POSS) as Reinforcing Agent for Waterborne Polyurethane Coatings on Wood

Polyhedral oligomeric silsesquioxane (POSS) was added as a reinforcing agent in waterborne polyurethane (WPU)-based coatings to improve their properties. The morphology, structure, thermal stability as well as mechanical properties of the resulting WPU and WPU/POSS hybrid films were investigated. The good compatibility of POSS in the WPU matrices was demonstrated by transmission electron microscopy. Furthermore, Fourier-transform infrared spectroscopy analysis (FTIR) suggested the successful bonding of POSS and WPU matrices. The thermal stability of WPU/POSS hybrids was improved than that of pure WPU according to thermal gravimetric analysis (TGA). The results also revealed the enhancement of the pencil hardness and abrasion resistance of the hybrid films compared with WPU. However, the pull-off adhesion slightly decreased from Grade 0 to Grade 2.