Synthesis of a graft‐functionalized flame retardant based on DOPO and its application on the surface of terylene/cotton fabrics

Abstract Terylene/cotton (TC) fabrics are widely used in the textile industry because of their superior softness and durability. In addition, its high combustibility leads to a great safety hazard, and the droplet phenomenon during combustion is particularly serious. 9‐oxa‐10‐phospha‐9,10‐dihydrophenanthrene 10‐oxide (DOPO) and its derivatives are frequently used as eco‐friendly flame retardants in large quantities in substrates. It would be difficult to apply to the surface of the fabric, and the addition of large amounts would lead to a decrease in the mechanical properties. Therefore, it is necessary to design a strategy for graft‐functionalized flame retardants that can be applied to surfaces. Here, this study reported a washing‐fastness flame‐retardant coating (DOPO‐p) synthesized from DOPO and p‐hydroxybenzaldehyde (p‐HBA), coatings with a low weight growth and high flame‐retardant efficiency are prepared by the strategy of dissolving with organic solvents. Water and dry‐cleaning tests showed excellent washing fastness of TC fabrics. In the limiting oxygen index (LOI) test, the finished fabric achieved a LOI value of 22.9%. In the cone calorimetry test, the peak of heat release rate of the finished fabric is decreased by 27% and CO 2 release is reduced by 29% when the coating weight growth was only 3.3 wt%.