Synthesis and characterization of waterborne UV-curable polyurethane modified with side-chain triethoxysilane and colloidal silica

A series of siloxane modified waterborne UV-curable polyurethane (WUPU) and its nanocomposites were synthesized using a diol with side-chain triethoxysilane (HEA-APTES) derived from 2-hydroxyethyl acrylate (HEA), 3-aminopropyltrimethoxysilane (APTES) and aqueous colloidal silica. The effects of HEA-APTES and silica on its colloidal, physico-chemical and surface properties were studied for WUPU and its nanocomposites. It was found that the incorporation of HEA-APTES enhanced Young modulus, tensile strength, surface hydrophobicity and water resistance of WUPU films. Furthermore, the introduction of silica nanoparticles further improved the modulus, tensile strength and water resistance of the HEA-APTES based WUPU films without damaging its surface hydrophobicity and transparency due to the homogeneous dispersion of silica clusters in the WUPU matrix.