Synthesis And Properties Of Modified Nanoparticles/Waterborne Polyurethane Nanocomposites

Waterborne polyurethane (WPU) have some merits such as no pollute, flame difficulty, few smell, energy saving, convenient processing for operations, so it have been widely used in adhesives, coatings, textile printing, leather finishing and other domains. In order to improve the performance of WPU and have a wider range of applications, the nano-particles/waterborne polyurethane compounds were prepared by reacting WPU with surface-modified nano-TiO₂ and nano-SiO₂ respectively to improve their resistance of staining, anti-aging, hardness and wear resistance.In order to improve the compatibility of nano-particles with WPU, nano-TiO₂ and nano-SiO₂ were respectively modified by TDI and PPG. The results of FT-IR and TGA showed that the TDI and PPG were successfully grafted on the surface of nano-particles. There were the highest rates of nano-particles organic grafting when the TDI: PPG =1:1. Settling experiments showed that the modified nano-particles have better dispersibility in acetone solvent than non-modified nano-particles, the settlement time of nano-particles were longest when the TDI: PPG =1:1. The grain size analysis and AFM showed that dispersibility of the modified nano-TiO₂ and nano-SiO₂ were improved.Nano-particles/waterborne polyurethane compounds were prepared by in situ polymeration by TDI with PPG, DMPA, BD, EDA, nano-particles and others. The viscosity, hardness, water absorption, acid resistance, aging resistance, staining resistance and wear resistance of resin were tested. Addition of nano-TiO₂, nano-SiO₂ both increased the viscosity and water resistance of water-borne polyurethane. The anti-aging and stain resistance of WPU were improved by addition of nano-TiO₂; the hardness and wear resistance of WPU were improved by addition of nano-SiO₂.