Effect of octa(aminopropyl) polyhedral oligomeric silsesquioxane (OapPOSS) functionalized graphene oxide on the mechanical, thermal, and hydrophobic properties of waterborne polyurethane composites

A novel graphene nanomaterial functionalized by octa(aminopropyl) polyhedral oligomeric silsesquioxane (OapPOSS) was synthesized and then confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM EDX), atomic force microscopy, and X-ray diffraction. The obtained functionalized graphene (OapPOSS-GO) was used to reinforce waterborne polyurethane (WPU) to obtain OapPOSS-GO/WPU nanocomposites by in situ polymerization. The thermal, mechanical, and hydrophobic properties of nanocomposites as well as the dispersion behavior of OapPOSS-GO in the polymer were investigated by TGA, a tensile testing machine, water contact angle tests, and field emission SEM, respectively. Compared with GO/WPU and OapPOSS/WPU composites, the strong interfacial interaction between OapPOSS-GO and the WPU matrix facilitates a much better dispersion and load transfer from the WPU matrix to the OapPOSS-GO. It was found that the tensile strength of the OapPOSS-GO/WPU composite film with 0.20 wt % OapPOSS-GO exhibited a 2.5-fold increase in tensile strength, compared with neat WPU. Better thermal stability and hydrophobicity of nanocomposites were also achieved by the addition of OapPOSS-GO. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44440.