Flame retardant and anti-dripping modification of polyamide 6 fabric by guanidine sulfamate with enhanced durability

Abstract

This study focused on durable flame retardant functionalization of polyamide 6 (PA6) fabric using guanidine sulfamate (GAS). The modified PA6 fabric self-extinguished during vertical burning test (ASTM D6413) without droplet; it had a low damaged length of 8.0 cm and a high LOI of 31.3%, showing good flame retardancy. However, the modified PA6 fabric showed poor washing durability. An anionic thin film on fiber surface was fabricated using condensed tannin resin to improve the washing durability. The electrostatic repulsion action between thin film and GAS contributed to a good washing durability of the modified PA6 fabric, reflected by the self-extinguishing ability after 20 washing cycles. The formation of incombustible violates suggested by thermal stability analysis was beneficial to dilute combustible gases, leading to improved flame retardancy of PA6 through a gas-phase mechanism. This work offers a novel approach of developing durable flame retardant PA6 textile by combining GAS modification and anionic resin coating.