The polymeric scale inhibition and dispersion agents (PAYS) were prepared by graft copolymerization of acrylic acid, allylpolyethoxy carboxylate (APEY) and 2-acrylamido-2-methyl-propanesulfonic acid by using ammonium persulfate as a radical initiator in aqueous solution, among which APEY was synthesized in laboratory. Structure of PAYS was characterized by Fourier transform infrared spectroscopy. Experimental data showed that the terpolymer was a high-efficient chelate sorbent, and it exhibited excellent ability for calcium orthophosphate, with approximately 96% efficiency at the dosage of 4 mg/L, as well as high efficiency toward barium sulfate scales nearly 80% inhibition. The effectiveness of PAYS depends on the agent concentration, temperature and the ratio of the reactant. The formation of Ca3(PO4)2 and BaSO4 precipitates was characterized by scanning electron microscopy. It appeared that the crystal shape, size, and the morphology of scale changed apparently at the dosage of 4 and 15 mg/L, respectively. In addition, it has good effect on controlling iron (III) scaling. This study was also devoted to the understanding of the action mechanism of these inhibitors in suppressing the crystal nucleus formation and preventing the crystal growth. Based on the contrast experiment of scale formation, the supposing mechanism diagram was also delineated and analyzed in detail. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41546.
A novel low-phosphorus terpolymer, used as scale, corrosion inhibitor, and dispersant for iron oxide, was prepared through free-radical polymerization reaction of acrylic acid (AA), oxalic acid-allypolyethoxy carboxylate (APEM), and phosphorous acid (H3PO3) in water with redox system of hypophosphorous and ammonium persulfate as initiator. Structure of the synthesized AA-APEM-H3PO3 terpolymer was characterized by Fourier transform infrared spectrometer and 1H-NMR. The polymer possesses excellent scale inhibition performance for CaCO3, outstanding ability to disperse ferric oxide, and good corrosion inhibition properties. The study showed that AA-APEM-H3PO3 exhibited excellent ability to control calcium carbonate scale, with approximately 90.16% CaCO3 inhibition at a level of 8 mg/L AA-APEM-H3PO3. The data of the light transmittance showed that, compared to hydrolyzed polymaleic acid and polyepoxysuccinic acid, AA-APEM-H3PO3 had superior ability to control iron ions scaling. The light transmittance of the solution was about 24.1% in the presence of the terpolymer when the dosage was 8 mg/L. Moreover, the corrosion inhibition efficiency could reach up to 79.77% at a dosage of 30 mg/L, with ethylene diamine tetra methylene phosphonic acid just 39.62%. Scanning electronic microscopy, transmission electron microscope, and X-ray powder diffraction analysis were used to investigate the effect of AA-APEM-H3PO3 on morphology of calcium carbonate scale. The low-phosphorous terpolymer has also been proven to be effective inhibitor of calcium carbonate even at increasing solution temperature, pH, and Ca2+ concentration. The proposed inhibition mechanism suggests the surface complexation and chelation between the functional groups P(O) (OH)2, COOH and Ca2+, with polyethylene glycol segments increasing its solubility in water. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41447.
In this study, we synthesized a novel double-hydrophilic poly(ethylene glycol) (PEG)-based crystal growth modifier polyethylene glycol double-ester of maleic anhydride/ acrylic acid named PEGDMA/AA, whose structure was still linear but also had some differences from a traditional chelating linear polymer, in which the PEG segment was incorporated. The scale inhibition behavior of PEGDMA/AA was evaluated by means of a static scale inhibition method. As the polymerization degree of PEGnDMA was 8 (n = 8), the maximum inhibitory toward calcium carbonate (CaCO3) and calcium sulfate (CaSO4) were 89.0 and 98.8% at dosage levels of 12 and 3 mg/L, respectively. Comparisons with other inhibitors were also carried out. Characterization of the CaCO3 and CaSO4 scales with scanning electron microscopy and transmission electron microscopy proved that great changes in the size and morphology of the calcium scales took place under the influence of PEG8DMA/AA. X-ray diffraction and diffraction patterns further confirmed the impact of PEG8DMA/AA as a crystal growth modifier. The three supposed mechanisms, (1) chelating solubilization, (2) multilayer type of adsorption, and (3) electrostatic repulsion function, are also described in detail. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39792.
