Chloramide copolymers from reacting poly(N-isopropylacrylamide) with bleach

Poly(N-isopropylacrylamide), PNIPAM, when reacted with aqueous NaClO at pH 10.5 gives a stable N-chloramide copolymer, poly(NIPAM-co-NIPAMCl) with little reduction in molecular weight. The copolymer is more hydrophobic than PNIPAM, and chlorination proceeded until the copolymer phase separated. Thus, the reaction temperature determined the extent of chlorination and the product cloud-point temperatures. Chlorination was reversed by reduction with Na2S2O3. NaClO treatment of PNIPAM at the lower pH of 8 gave extensive chain degradation.