Nano-ceria and nano-zirconia reinforced polyurethane nanocomposite-based coated textiles with enhanced weather resistance

Abstract

This work reports the effect of nano-ceria or cerium oxide (CeO2) nanoparticles and nano-zirconia or zirconium oxide (ZrO2) nanoparticles on the weather resistance property of polyurethane (PU) based coatings. The concentrations of ceria and zirconia nanoparticles (NPs) were varied in the PU coating formulation to obtain optimum weather resistance property. The prepared PU/ceria and PU/zirconia nanocomposite-based formulations were coated on a high strength polyester fabric by a knife coater. Coated fabrics were exposed in a weather-o-meter up to 300 h, in accelerated weathering conditions by controlling UV irradiance, humidity, temperature and dry/wet state. The weather resistance performance was analyzed by studying the UV protection factor (UPF) and the change in tensile properties (tensile strength and breaking extension). The chemical change after UV exposure was analyzed by Fourier Transform Infrared Spectroscopy (FTIR). The surface morphology was investigated before and after exposure by observing the tropology of the coated surface under SEM. Both the nanoparticles (ceria and zirconia) showed a great potential in enhancing the weather resistance property of PU-coated fabrics, while the weather resistance improved gradually with increasing the concentration of nanoparticles up to a certain percentage (5 wt%). After 300 h UV exposure, the change in carbonyl index (CI) was 25%, 8.6% and 12.8% for the fabrics coated with neat PU, PU/ceria (5 wt%) nanocomposite and PU/zirconia (5 wt%) nanocomposite, respectively. The photooxidative index (PI) of PU/ceria nanocomposite was also much lower than the PU/zirconia nanocomposites, especially at higher concentration of nanoparticles (5 wt% and 10 wt%). In case of PU/ceria nanocomposites, this significantly low CI and PI values indicated their better weather resistance potential compared to the PU/zirconia nanocomposites. As a consequence, after 300 h UV exposure, the percentage retention in tensile strength was significantly high for the fabric coated with PU/ceria nanocomposite (72%) in comparison to the neat PU (only 30%) and PU/zirconia nanocomposite (48%) coated fabric.