Evaluation of maleic acid‐based copolymers containing polyoxyethylene ether as inhibitors for CaCO3 scale

ABSTRACT Polymer scale inhibitors have been widely used to reduce the loss caused by mineral scaling in circulating cooling water systems. In this article, four maleic acid‐based copolymers [hydrolyzed polymaleic anhydride (HPMA)‐AEO] containing different fatty alcohol polyoxyethylene ether (such as AEO‐9, AEO‐10, AEO‐15, and AEO‐20) are prepared by the way of free‐radical copolymerization and characterized using Fourier transform infrared (FTIR), 1H NMR, and gel permeation chromatographic (GPC) techniques. The effects of HPMA‐AEO on CaCO3 scale are studied in several aspects (such as dose, Ca2+ concentration, temperature, inhibition time, pH, the ratio of EO:carboxyl, and the relative supersaturation of CaCO3 solution) by static experiments. The CaCO3 scaling process with dosing of HPMA‐AEO‐9 is investigated under dynamic tests. CaCO3 deposits and precipitate in the presence of HPMA‐AEO‐9 are analyzed using scanning electronic microscope (SEM) and X‐ray diffraction (XRD). The results show that the performance of HPMA‐AEO against CaCO3 scale highly depends upon the ratio of EO:carboxyl; the introduction of AEO group can significantly improve the performance of HPMA‐AEO to tolerate high alkalinity, high hardness, and high temperature; the presence of HPMA‐AEO‐9 can obviously affect the CaCO3 scaling process on the tube wall through interfering with nucleation process and crystal growth process and significantly alter the surface morphology and crystal form of CaCO3 deposits. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47470