Design and preparation of flame-retardant cellulose fabric with low strength loss using polycarboxylic acid as crosslinker

To decrease strength loss of flame-retardant cotton fabric using polycarboxylic acid as the crosslinker, a series of multi-amino phosphoramide (BPEI/DPn) was synthesized using branched polyethyleneimine (BPEI) and dimethyl phosphite (DP). The flame retardant coating was fabricated on cotton fabric with the assist of 1,2,3,4-butanetetracarboxylic acid (BTCA). The optimum multi-amino phosphoramide was obtained by investigate the effect of different BPEI/DPn on washing durability and flame retardancy of modified cotton fabrics. The results found that BPEI/DP4 (mole ratio of BPEI and DP was 1:4) coated cotton fabric presented superior flame retardancy with self-extinguishing action and 27.9% of LOI value. Also, this flame-retardant cotton fabric can withstand a certain number of standard washing cycles. The heat and smoke release of cotton fabric during the combustion were significantly inhibited after modification with BPEI/DP4, and HRR value decreased by 35.0% compared with the unmodified cotton. Additionally, BPEI/DP4 can greatly improve the mechanical capability of cotton fabric modified with BTCA, and almost 80% of breaking force can be remained owning to partially neutralizing the acidic circumstance of BTCA solution, which might provide an efficient method to prepare functional cotton fabric with high performance.