羧酸聚合物阻垢机理的分子动力学研究

Scale Inhibition Mechanism of Carboxyl-copolymer to Calcite Based on Molecular Dynamics

采用分子动力学(MD)方法模拟研究了溶液体系中聚合物阻垢剂分子聚甲基丙烯酸丙酯(PMA)与方解石(110)、(104)晶面的相互作用,分析了PMA的阻垢效果。结果表明,阻垢剂分子PMA具有良好的阻垢作用,且对方解石(110)晶面生长的抑制作用更大一些;阻垢剂分子在MD模拟前后发生了显著的形变,且位于分子链端的羧基比链中部羧基的翻转角度大,因此链中部羧基更易与方解石晶面结合,其防垢效果比链端羧基好。由于两晶面呈现不同的电性,因此水分子在两晶面上的空间分布是不同的,这影响到了PMA对不同晶面的阻垢效果。

The interaction between Polypropyl methacrylate （PMA） and calcite crystal is simulated by mo- lecular dynamics （MD） method, and the inhibition effect of PMA on calcite crystal is analyzed. Results show that the scale-inhibitor PMA has a well effect on inhibiting the formation of calcite scale, and the in- teraction energy on calcite （110） surface is stronger than that on surface （104）. The PMA molecule de- forms significantly when it interacts with calcite surfaces, and the carboxyls show different behaviors at different position of PMA chain. Carboxyls at the end of chain have a more oscillate range than those in the middle, so the latter may inhibit calcite crystal growth more efficiently. The behaviors of water solutions are different on two calcite surfaces because of their different charged states, and the electropositive calcite （1-10） surface is more hydrophilic than the neutral calcite （104） surface, which results in the better effect of scale inhibition on （110） surface.