Waste gelatin based layer by layer assembly for sustainable solution to cotton fabrics flame retardancy

Abstract

Cotton fabrics are the main textile material in the daily life, but they may threaten people's lives and property when encountering flame due to its flammability. However, traditional halogen-containing flame retardancy strategies were considered owning health risks for human and perceived environmental concerns. In this work, bio-based gelatin extracted from scrap skin in leather processing, which is the component of the carbon source, was utilized for layer-by-layer assembly constructing intumescent flame-retardant coating onto cotton fabrics surface. The flame retardancy of the treated cotton fabrics was significantly improved, as showed by the limited oxygen index values of 28.5 for the cotton fabrics sample with 6 bilayer gelatin/ammonium polyphosphate (GL/APP) coating. Simultaneously, vertical burning test illustrated that the GL/APP coated fabrics exhibited excellent self-extinguishing behavior, and resulting in 63% maximum reduction in peak heat release rate obtained from Micro-scale Combustion Calorimeter tests for C200-6BL sample. These LbL-assembled cotton fabrics also presented excellent breathability and hygroscopicity, and would maintain good perspiration absorption and moisture removal properties in the practical application. Considering their healthy, eco-friendliness, low cost, and excellent flame retardant efficiency, GL/APP coatings can be considered as promising sustainable flame retardant strategy for cotton fabrics.