Eco-friendly Modal/alginate knitted fabrics with intrinsic flame retardancy and wearability

Flame-retardant Modal fabrics were prepared by blending Modal fibers with calcium alginate fibers, which have intrinsic flame retardancy, and the preparation process of flame-retardant samples is diametrically eco-friendly. Despite alginate fibers being low in thermal stability, the char-forming ability of Modal/alginate samples was given greater value in a higher temperature range without changing the degradation process of Modal fibers. Modal(50)/alginate(50) obtained 23.0% char residue at 700 ? with an increase of 82.5% in N-2 and received a 29% and 51% reduction of total heat release and peak heat release rate, respectively, according to the cone calorimeter test. The scanning electron microscopy results indicated that more integrated fibers remained after burning. The Ca2+ from calcium alginate fibers could catalyze the carbonization of Modal fibers to form a char layer, which could inhibit oxygen and heat transfer. Moreover, Modal/alginate samples reduced the release of flammable volatiles. It was proved that this environmentally benign treatment hardly influenced the wearability of Modal fabrics through resilience, softness, smoothness properties, a bursting strength test, moisture penetrability, and air permeability. These results indicate that it is possible to obtain Modal/alginate knitted blended fabrics with improvements in both flame retardancy and retention of wearability.