Durable Flame Retardant Nylon-6,6 by Microwave-Assisted Surface Grafting of Polyacrylamide

A microwave-assisted surface grafting of polyacrylamide (PAAm) enabling durable flame resistance on nylon-6,6 fabric is presented. The PAAm grafted nylon-6,6 (PAAm-g-nylon-6,6) fabric is characterized by FTIR and H NMR. Self-extinguishing nylon-6,6 fabric with a char length of 7.7 cm and after-flame of 2 s in the ASTM D6413 vertical flame test is achieved with 7–8% PAAm grafting. The melt/flame dripping behavior of neat nylon-6,6 is also significantly suppressed by PAAm through enhanced char formation and a gas dilution mechanism, as observed in thermogravimetric analysis. The laundry test followed by the vertical flame test and heat release characterization of PAAm-g-nylon-6,6 suggests that the robust grafting of PAAm provided durable flame resistance to nylon-6,6 fabric. The PAAm-g-nylon-6,6 exhibits a char length of 6.1 cm and an afterflame of 0 s after 20 standard laundry cycles.