Performance of Fluorescent Whitening Agents for Polyester in a Yellowing Test with an Unrealistically High Concentration of Nitrogen Oxides

To test the yellowing tendency of fluorescent whitening agents (FWAs) for polyester on exposure to nitrogen oxides, McEwan and Murdoch proposed a rapid test using an unrealistically high concentration of these gases. Our studies have shown that this test induces yellowing reactions that are associated with the high nitrogen oxide concentration, but which do not occur under practical conditions