A new class of hyperbranched polymeric scale inhibitors

Addition of anionic vinylic monomers, vinyl phosphonic, vinyl sulfonic, acrylic acid, maleic acid and aconitic acid, to hyperbranched polyethyleneimines produced a series of polymers which have been investigated for their performance as scale inhibitors to prevent the deposition of calcium carbonate and barium sulfate. Dynamic performance tests were carried out in high pressure tube blocking equipment at 1200 psi and 100 °C. All the new inhibitors exhibited both carbonate and sulfate scale inhibition, the best performance being for the aconate-derived polymer on carbonate scale and the phosphonate-derived polymers on sulfate scale.Seawater biodegradation data on hyperbranched polyethyleneimines has not been reported previously. Polymers with molecular weights (Mw) of 300 and 1200 gave 10 and 19% seawater biodegradation respectively over 28 days in the OECD306 test. However, hyperbranched polyethyleneimine with molecular weight 1200 functionalised with maleic acid or aconitic acid showed higher biodegradation rates of up to 34% in 28 days and increasing to over 60% in 60 days. This reflects the ability of bacteria to attack and digest alkylenecarboxylate groups more readily than the amine-based polymer backbone.

► A novel class of hyperbranched scale inhibitors has been prepared.
► Polymers shows moderate inhibition of carbonate and sulfate scale.
► Increasing carboxylation gave improved seawater biodegradation for the polymer.