UV-curable organic silicone grafting modified waterborne polyurethane acrylate: Preparation and properties

The organosilicon grafting copolymerization waterborne polyurethane acrylate composite coating (WPUA@KH570) with high surface properties was prepared by the UV curing method from mixing silicone monomer surface-modified ZnO (Si@ZnO) as photoinitiator to waterborne polyurethane acrylate (WPUA) emulsion. The effects of the polyurethane isocyanate index (R), the addition amount of hydrophilic chain elongator DMBA (wDMBA), the ratio of PU/PA on the stability of the synthesized WPUA emulsion were explored. The properties of the WPUA@KH570 composite coatings with different contents of organosilicon surfacemodified ZnO were characterized by the particle size distribution meter, FTIR, XRD, SEM, UV-Vis-NIR spectrophotometer, contact angle (CA) and water absorption rate (WAR). The results showed that when R = 1.4, wDMBA = 0.04 and PU/PA = 0.6, the WPUA emulsion had an excellent stability. When the content of organosilicon modified ZnO reached 1.5 wt%, the CA increased to 90.6 degrees, the WAR decreased to 15.4 %, and the absorbance reached 0.5. The WPUA@KH570 composite coating could be changed from hydrophilic to hydrophobic, which can step further promoted the surface properties, water resistance and UV absorption.