Flame retardation of cellulose-rich fabrics via a simplified layer-by-layer assembly

• A ‘simplified’ LbL assembly was developed for the effectively flame-retarding cotton fabrics.
• Reduction of pHRR and THR for cotton fabrics with 5wt% of coating was 51% and 37%, respectively.
• This one-pot and water-based deposition is fast-treated, eco-friendly and wash durable.

Due to the high cellulose content of cotton (88.0–96.5%), the flame retardation of cotton fabrics can be achieved via an approach for the flame retardation of cellulose. In this work, a facile water-based flame retardant coating was deposited on cotton fabrics by a ‘simplified’ layer-by-layer (LbL) assembly. The novel coating solution was based on a mild reaction between ammonium polyphosphate (APP) and branched polyethyleneimine (BPEI), and the reaction mechanism was studied. TGA results showed that the char residues of coated fabrics were remarkably increased. The fabric with only 5wt% coating showed self-extinguishing in the horizontal flame test, and the peak heat release rate (pHRR) in cone calorimeter test decreased by 51%. Furthermore, this coating overcame a general drawback of flame-retardant LbL assembly which was easily washed away. Therefore, the simplified LbL method provides a fast, low-cost, eco-friendly and wash-durable flame-retardant finishing for the cellulose-rich cotton fabrics.