Enhancing flame retardancy, antibacterial activity and UV resistance of polyamide 66 fabric by fully biobased intumescent flame-retardant nanocellulose coating.

Polyamide 66 (PA66) fabric, one of the most common textile materials, presents great fire hazards to human safety and property due to its intrinsic flammability. In this study, fully biobased intumescent flame-retardants (IFRs) composed of cellulose nanocrystals (CNC), tannic acid (TA) and phytic acid (PA) were synthesized and coated onto the surface of the PA66 fabric for improving the flame retardancy, antibacterial and UV resistance. It is found that IFR coating effectively suppressed the droplet and smoke phenomenon of PA66 fabric, and the total smoke production (TSP) and smoke production rate (SPR) values of the fabric were significantly reduced by 71.0 % and 36.7 %, respectively. The synergistic effect of condensed phase and gas phase flame retardancy could be responsible for the remarkable improvement in the flame-retardant property of the treated PA66 fabric (PA66/IFR). Owing to the TA in the IFR coating, PA66/IFR3 fabric showed obvious antibacterial activity and UV resistance. Furthermore, the PA66/IFR3 fabric retained adequate mechanical properties and maintains satisfactory air permeability. This study provides a green and convenient solution for developing multifunctional PA66 fabrics to meet diversified demands.