Cellulose Nanofibril-Based Flame Retardant and Its Application to Paper

A cellulose nanofibril-based flame retardant has been developed by phosphorylation of cellulose with P2O5, promoted by ball milling and followed by treatment with melamine. The width of cellulose nanofibrils obtained through a combination of chemical and mechanical action was 1.2–4.8 nm. Phosphorylated cellulose nanofibril was combined with melamine through ionic bonding and added to bamboo pulp paper to improve flame retardancy. The flame retardancy of the paper loaded with the cellulose nanofibril-based flame retardant increased with increasing content. The limiting oxygen index was 30% for 30 wt % retardant-loaded paper, and the peak heat release rate was 62.8% lower than that of the control. The paper showed remarkable self-extinguishing behavior. The dry and wet tensile strengths of the paper loaded with the cellulose nanofibril-based flame retardant were also enhanced.