苯骈三氮唑与苯甲酸钠在气相防锈膜中扩散机理的分子动力学模拟研究

Molecular Dynamics Simulation of Diffusion Behavior of Benzotriazole and Sodium Benzoate in Volatile Corrosion Inhibitor Film

使用分子动力学模拟的方法,从分子水平研究了不同温度下苯骈三氮唑与苯甲酸钠在低密度聚乙烯中的扩散行为,探究了缓蚀剂的扩散机理。结果表明,苯骈三氮唑的扩散速率较苯甲酸钠小,且均随温度的升高而增大;多组分扩散时苯骈三氮唑、苯甲酸钠的扩散速率减缓并随苯甲酸钠含量的增加而减小。缓蚀剂分子间的相互作用及缓蚀剂分子与扩散体系间的相互作用是影响其扩散的重要原因,苯甲酸钠对苯骈三氮唑的扩散可能存在抑制作用。缓蚀剂扩散系数的实验值与模拟值变化趋势一致,在数值上相差一个数量级。可为缓蚀剂的释放调控及复配提供技术支持。

The diffusion behavior of benzotriazole and sodium benzoate in low-density polyethylene of volatile corrosion inhibitor film was studied via a constant temperature and humidity chamber at different temperature,as well as molecular dynamics simulations at the molecular level,comparatively.The effect of the shape and size of the corrosion inhibitor molecules,temperature,free volume of the diffusion system,self-diffusion in low density polyethylene,and the interaction energy between the corrosion inhibitor molecules,and the low-density polyethylene on the diffusion rate of the corrosion inhibitors was analyzed.The results show that the diffusion rate of benzotriazole and sodium benzoate in the low-density polyethylene increased with increasing temperature,moreover,the diffusion rate of the single benzotriazole was less than that of sodium benzoate.When co-existence of benzotriazole and sodium benzoate in the polyethylene,their diffusion rates lowered in contrast to that the polyethylene containing only one inhibitor either benzotriazole or sodium benzoate,and which decreased with the increasing sodium benzoate content.The interaction between the corrosion inhibitor molecules and the interaction between the corrosion inhibitor and the diffusion system were important factors affecting the diffusion of the corrosion inhibitor,and the diffusion of sodium benzoate may have an inhibitory effect on the diffusion of benzotriazole.The measured and simulated diffusion coefficients of benzotriazole in low-density polyethylene show the same variation trend,but their values differ by one order of magnitude.Even so,the result can still provide a technical reference for release control and formulation of corrosion inhibitors.