Modification of cellulose fibers with phytic acid and its application in flame-retardant paper preparation

The flammability of most decorative paper poses a potential fire hazard to buildings. In this study, softwood fibers were modified with phytic acid and urea to obtain phytic acid esterified cellulose (PAEC) with good flame-retardant properties. Due to the introduction of phosphorus and nitrogen elements in PAEC, the heat release rate (HRR) and total heat release (THR) decreased from 170.9 W/g and 7.6 kJ/g to 104.3 W/g and 4.9 kJ/g, respectively, when compared with raw fibers. Subsequently, PAEC was composited with talc powder, carboxylated nanofibers, and calcium ions to prepare flame retardant paper. The results indicated that the HRR of the 170.9 W/g of the paper was decreased to 47.0 W/g. The network structure formed by the cross-linking between carboxyl groups in nanofibers and Ca 2⁺ enhanced the paper’s mechanical properties. The strength reached 12.18 MPa, which was 1.4 times as high as that of raw paper. Therefore, the prepared flame-retardant paper is expected to provide a candidate for the preparation of decorative paper. Graphical abstract