Low molecular weight poly(acrylic acid) with nitrilodi(methylenephosphonicacid) chain ends for scale inhibition

Poly(acrylic acid) with molecular weight of 5000 was produced by using 2-am inoethanethiol hydrochloride as chain transfer agent. Amine chain end group s of the resulting polyacrylic acid were transfer med into nitrilodi(methyl enephosphonic acid) by reacting formaldehyde-phosphorous acid in the presen ce of hydrogen chloride. H-1 NMR, P-31 NMR and microanalysis were used for structural analysis. The modified polyacrylic acid had much better calcium carbonate scale inhibition effect than commercial poly(acrylic acid).