Preparation of waterborne polyurethane nanocomposite reinforced with halloysite nanotubes for coating applications

To construct waterborne polyurethane with excellent water resistance and mechanical properties, an organic-inorganic hybrid nanocomposite based on modified halloysite nanotubes (mHNTs) and polyurethane was prepared. The HNTs were modified with an amino-silane coupling agent (KH550) and then reacted with polypropylene glycol, 2,2-Dimethylol propionic acid, and Toluene diisocyanate to form mHNTs/PU aqueous dispersions. The structure of the siloxane functionalized mHNTs was confirmed by a Fourier transform infrared study. The PU/mHNTs composites were characterized by using differential scanning calorimetry, scanning electronic microscopy, thermal gravimetric analysis, a tensile test, particle size analysis, and a water swelling experiment. The tensile strength, Young's modulus, and elongation at the break of the composite polymer with 0.5 wt % mHNTs was shown to be significantly improved, by approximately 200%, 200%, and 30%, respectively. An excess amount of mHNTs could weaken the reinforcing effect and stability of the composite emulsion. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43949.