Facile chemical modification of poly(vinyl alcohol) to an organosoluble, flame-retardant copolymer using dichloroacetic acid

Applications of poly(vinyl alcohol) (PVOH) are largely limited due to its poor flame resistance. In this work, organosolubility, and flame resistance are imparted to PVOH through green chemical transformation using dichloroacetic acid (DCAA). Unlike the conventional solvent-based strategies, PVOH was modified by simply mixing it with DCAA and heating the mixture without employing any additional reagents/catalysts/solvents. This resulted in the formation of a random copolymer, poly(vinyl alcohol-co-vinyl dichloroacetate), which was not soluble in water but was soluble in organic solvents such as acetone, methanol, and dimethylsulfoxide. Furthermore, the copolymer was inherently self-extinguishing, and did not melt drip or show glowing combustion. Additionally, dummy currency notes coated with this copolymer displayed exceptional self-extinguishing and non-glowing properties when removed from the flame, proving the copolymer's suitability for flame-retardant sizing/coating applications.