Preparation And Characterization Of The Waterborne Polyurethane Nanosilica Composites

The waterborne polyurethanes(WPU)with low concent of Volatile Organic Component(VOC)have been widely used in printing,leather,coating,bond(adhesive), architectural,paper-making and other vocation.To spread their using scope,we have to improve the properties of aqueous polyurethanes.Cause of the excellent performance and lower cost,Nano-SiO₂ was used to modified WPU.In this paper we use Nano-SiO₂ to composite with WPU,then add crosslinking agentγ-isocyanatopropyltriethoxysilane to enhence the properties of WPU.The method of silane sol-gel was used to modify the Nano-SiO₂ to obtain the modified silica particles and dispersoid.Then isophoronediisocyanate(IPDI), polycarbonate diol(PCD-1000),Poly(1,4-butylene adipate)diol(PBA),dimethylol propionic acid(DMPA)and N-methyl-2-pyrrolodone(NMP)were used as the main materials,adding the modified silica particles,we can receive the prepolymer, emulsification and chain extension an aqueous dispersion(WPUNS)was prepared.The properties of WPU such as viscidity,rigidity,Tensile strength,Elongation at break,water absorption was analysed in this paper.Discussing the different methods and amount of adding nano-SiO₂,we found that WPU in in-suit polymerization have better in decentralization and resistance to high temperature and water than the blending method.In order to improve the properties of WPUNS,we added the curing agent,the isophoronediisocyanate(IPDI),polycarbonate diol(PCD-1000),Poly(1,4-butylene adipate) diol(PBA),dimethylol propionic acid(DMPA)and Hydroxyethyl acrylate(HEA)were used as the main materials to prepare the WPU;The WPUNS'properties were characterized and the influence of the way and the amount of addingγ-isocyanatopropyltriethoxysilane were discussed.