Preparation of a Reactive Phosphorus/nitrogen-Based Intumescent Flame Retardant Coating for Cotton Fabrics

Abstract

This study focuses on the synthesis of a reactive phosphorus-/nitrogen-based intumescent flame retardant (IFR) agent using diethyl phosphite, urea, and glutaraldehyde through Kabachnik-Fields reaction. We further studied the potential applications in IFR modification of cotton fabrics through surface coating approach. The chemical structure of IFR agent and its potential grafting action with cotton fibers were characterized. The thermal stability, smoke and heat release performance, flame retardancy, and durability of the IFR-coated cotton fabrics were explored. Char residue analyses were also performed to confirm the FR mechanism of IFR coating. The results revealed that IFR coating significantly inhibited the heat and smoke generation of cotton. The IFR coating showed high functional efficiency due to phosphorus/nitrogen synergism. The IFR-coated fabrics passed vertical burning B1 level and obtained an limiting oxygen index (LOI) value of higher than 32.0%. The introduction of IFR coating to cotton by covalent bonds imparted excellent washing resistance to cotton as indicated by the self-extinguishing action of the IFR-coated cotton fabrics after 10 launderings. In general, the present study offers a novel strategy to prepare reactive and efficient IFR coating for cellulose-based textiles.

Keywords

• cotton
• flame retardancy
• surface coating
• intumescent flame retardant
• kabachnik-fields