Flame-retardant and antibacterial multifunctional cellulose fibers with carbamate esterification and phosphorylation modification

Cellulose is rich in hydroxyl groups, which can be modified by chemical methods to realize the functionalization of cellulose and expand its application range. In this study, cellulose fibers were chemically modified by carbamate esterification and phosphorylation to obtain excellent intrinsic flame-retardant properties. Additionally, the antibacterial property was given through further chlorination. The chemical and physical properties of cellulose with and without modification were investigated. The contents of nitrogen and phosphorus in different modified cellulose fibers were determined. The flame retardant and antibacterial properties of the modified cellulose fibers were evaluated. The results indicate that with increasing phosphate addition, the nitrogen (N) and phosphorus (P) contents in modified cellulose fibers increased initially and then decreased, reaching their respective peaks at an addition of 5 g. The flame-retardant properties of modified cellulose can be visually observed through combustion experiments. The miniature combustion calorimeter test demonstrated that cellulose carbamate's heat release rate value decreased from 257.6 W/g to 25 W/g after phosphorylation. The chlorinated modified cellulose achieved a 99.9 % inhibition rate against both Staphylococcus aureus and Escherichia coli . This method effectively endowed cellulose fiber with intrinsic flame retardant and antibacterial properties, creating a prospective application for cellulose derivatives. • Phosphorylated cellulose carbamate (PCC) with flame retardancy was synthesized. After chlorination, PCC-Cl showed excellent antibacterial performance