Effect of genipin crosslinked layer-by-layer self-assembled coating on the thermal stability, flammability and wash durability of cotton fabric.

A crosslinked and flame retardant coating was fabricated by layer-by-layer self-assembly on cotton fabric. The coated fabric was treated using positively charged polyethylenimine (PEI) and negatively charged hypophosphorous acid-modified chitosan (HACH) with subsequent crosslinking with genipin. The thermal stability and flammability of the treated cotton fabric were investigated by thermogravimetric analysis (TGA), the horizontal flame test and microscale combustion calorimetry. TGA results showed that, in an air atmosphere, there was more char residue for the treated cotton fabrics than for the untreated cotton fabric. The cottons treated with a 10-bilayer coating (C-(PEI/HACH)10 and C-(PEI/HACH)10-crosslink) could extinguish the fire during the horizontal burning test. The peak heat release rate and total heat release rate of C-(PEI/HACH)10 were reduced by 73% and 80%, respectively, compared with those of the untreated one. At the same time, the genipin crosslinked PEI/HACH coating exhibited good wash durability and mechanical properites for the treated fabrics.