Comparative study of polycarboxylic acids for sustainable crosslinking of silk fabrics: Evaluating flame retardancy and physical performances.

For protein fibers, polycarboxylic acids represent a green strategy to enhance durability without using formaldehyde. This study evaluated the physical and flame retardant properties of silk fabrics treated with three formaldehyde-free crosslinkers: citric acid (CA), 1,2,3,4-butanetetracarboxylic acid (BTCA), and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA). Results showed that these acids bond with silk protein through esterification and amidation, improving washing durability.