Study on the Scale\nInhibition Performance and Mechanism\nof a High-Performance Graft Copolymer Cellulose Green Scale Inhibitor\non Oilfield Ca<sup>2+</sup>

Carboxymethyl cellulose (CMC), acrylic acid (AA), acrylamide\n(AM),\nand 2-acrylamido-2-methylpropanesulfonic acid (AMPS) were subjected\nto graft copolymerization through a free radical polymerization process,\nyielding four distinct CMC-<i>g</i>-P(AA-<i>co</i>-AM-<i>co</i>-AMPS) scale inhibitors. The assessment revealed\nthat the scale inhibitors significantly mitigated the formation of\nthe CaCO<sub>3</sub> scale, with an inhibition efficiency ranging\nfrom 98% to 100%, surpassing that of unmodified CMC by a factor of\nmore than three. The mechanism of scale inhibition was confirmed utilizing\nstatic scale inhibition experiments, scanning electron microscopy\n(SEM), X-ray diffraction (XRD), zeta potential, and molecular dynamic\nsimulation. Additionally, the impact of the grafting ratio and graft\nchain distribution on the inhibition efficiency was scrutinized. It\nwas established that, among samples with comparable grafting ratios,\nthose with a higher average number of graft chains exhibited a greater\nnumber of active inhibition sites, leading to enhanced scale inhibition\nefficacy. The presence of inhibitors induces dispersion and chelation,\nwhich in turn cause lattice distortions in CaCO<sub>3</sub> crystal\nnuclei, thereby kinetically stabilizing the vaterite and aragonite\npolymorphs. This research presents a methodology for developing scale\ninhibitors suitable for oil field applications and furnishes theoretical\nunderpinnings for the fabrication of efficient and eco-friendly scale\ninhibitors.