Direct radiation grafting of acrylic acid to nylon‐6 fabric and the behaviour of the resulting graft copolymer

The role of certain cations as homopolymer inhibitors in the direct radiation grafting of acrylic acid to nylon‐6 fabric was investigated. The grafting solution was methanol and water at a ratio of 30 : 70 vol%. The maximum graft yield was obtained at 0·08 wt% when using Fe 2+ and at 0.7% for Fe 3+ . In addition, the graft yield obtained with the latter ion was higher than that for the former. Moreover, the presence of Na + and K + salts in concentrations as low as 0·1 wt% caused an increase in the graft yield. The hydrophilic properties investigated indicated that the water absorption of nylon‐6 fabric after 9 days increased by 44 times after grafting with poly(acrylic acid) at 166% graft yield. This ratio became 123 times, when this graft copolymer was transformed to the sodium salt. These ratios became 105 and 490 times for the corresponding recrystallized forms, respectively. A study was made to gain a better understanding of the observed super water absorption using SEM and DSC analysis. SEM micrographs of the recrystallized copolymer indicated the formation of large pores with a dendritic structure. Moreover, DSC showed a decrease in both the heat of fusion and melting point. The grafted nylon‐6 fabric showed a noticeable affinity for different dyestuffs.