Water-proof Breathable Coatings Based on Poly(vinyl alcohol) for Cellulosic Fabric

Hydrophilic breathable coatings were developed by coating the cotton fabric with poly(vinyl alcohol) (PVA) solution (20 wt%) containing poly(acrylic acid) (PAAc) (10% neutralized using sodium hydroxide) as a cross-linker, followed by drying and curing. The effect of cross-linker concentration and add-on on the properties of coated textile was studied. The coated substrate with the combination of molar ratio of PVA to PAAc of 25 and coating add-on of 18 wt% was found to have high integrity with the optimum breathable properties. This sample showed high resistance to hydrostatic head at 1400mm and very high water vapor transmission rate (WVTR) at 2165g/m ² 24 h, which was ~50% of the WVTR value shown by the uncoated substrate (cotton fabric). Physical investigation of the surface morphology showed that the coating was continuous without cracks or pin holes and appeared to be well adhered to the substrate even after a harsh wash.