Preparation And Study Of Waterborne Poiyurethane Nanoscale Composites

Waterborne polyurethane, WPU, has been developed because of their excellentproperties such as low toxicity and environment friend, energy conservation andsafety. Thereby it can be applied as an excellent replacement for the organic solvent-type polyurethane materials. Compared with other water-based resin, WPU has highertensile strength, better film performance, firmly attaching property, higherheat-resistance, cold durability and flexibility. WPU has a significant bindingcapability on the plastic and glass surface, and has been widely used in the textileindustry coatings, finishing agent of leather, fiberglass cluster, PVC adhesives, rubber,etc.However, the properties of WPU need to be further improved for its poor waterand organic solvent resistance as compared with organic solvent type polyurethane. Inorder to broaden the application of WPU, it is necessary to improve thecomprehensive properties of waterborne polyurethane. In recent years, the work ofmodification of WPU has been divided into several categories, including modificationby epoxy resin, silicone, acrylate and nano particles. Alternatively this thesis providesa novel mdodification method of WPU by functionallization of inorganic particles.Here, the WPU nanocomposites were prepared by in situ polymerization offunctionalized inorganic nanoparticles. To improve the dispersion ability of thenanoparticles in the organic phase, the surface of the particles are modified by OA andpoly (propylene glycol) phosphate ester(PPG-P). Fourier transform infraredspectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electronmicroscopy (SEM) and water absorption analysis had been performed to characterizethe structure, thermal stability, morphology and water resistance of the WPUnanocomposites, respectively. The main conclusion of this study are listed as below: (1) The preparation and characterization of WPU/CaCO3nanocomposites.Nano-CaCO3particles modified with PPG-P were used for in-situ preparation ofWPU/CaCO3nanocomposites. The heat resistance, water resistance and hardness ofthe composite films had been greatly improved for the well-dispersion of thenano-CaCO3particles.(2) The preparation and characterization of WPU/SiO2nanocomposites.Nano-SiO2particles modified with OA and PPG-P respectively were used for in-situpreparation of WPU/SiO2nanocomposites. The heat resistance, water resistance andhardness of the composite films had been greatly improved for the well-dispersion ofnano-SiO2particles.(3) The preparation and characterization of WPU/TiO2composites. TiO2particles were with OA and PPG-P respectively were used for in-situ preparation ofWPU/TiO2composites. The heat resistance, water resistance and hardness of thecomposite films had been greatly improved for the well-dispersion of TiO2particles.