硬脂酸包覆滑石粉对水在环氧涂层中传输性能的影响

Effect of Talcum Powder Filler Coated by Stearic Acid on Diffusion Behavior of Water Through Epoxy Coatings

利用电化学阻抗谱技术,研究了在环氧树脂涂层中,硬脂酸包覆滑石粉的用量与阻抗变化趋势。通过计算求出了硬脂酸不同包覆浓度时,水在涂层中的扩散系数。结果表明,经硬脂酸包覆的滑石粉颜料在环氧树脂涂层中,具有降低水扩散系数的作用。在环氧树脂涂层中,硬脂酸包覆的滑石粉填料存在一个临界包覆浓度0.5%(质量分数),当包覆量小于临界包覆浓度时,水在涂层中的扩散系数随着包覆量的增大而减小,当大于临界包覆浓度时,硬脂酸将影响涂层对基材的附着力而失去防腐的作用,包覆前的水的扩散系数为3.01×1010/(cm2.s-1),当包覆质量分数为0.5%时包覆后水扩散系数为最小0.89×1010/(cm2.s-1)。

By means of electrochemical impedance spectroscopy （EIS）, the impedance variation of epoxy coatings with talcum powder filler coated by stearic acid was studied. The diffusion coefficients of water through epoxy coatings with talcum powder filler coated by stearic acid with different concentrations were calculated. The experimental results show that the stearic acid-coated talcum powder filler in the epoxy coatings has a function of decreasing water diffusion coefficient. In this epoxy coating system, the talcum powder filler coated by stearic acid has a critical coating concentration（0. 5% ）. When the coating concentration is less than the concentration, the diffusion coefficient decreases with the increase of coating concentration, while when the coating concentration is higher than the concentration, the filler influences adhesion between the coating and substrate, as a result, stearic acid can cause the loss of corrosion protection. Meanwhile, the calculations show that without coating the filler, the diffusion coefficient of water is 3.01 × 10^10/（cm^2 · s^-1 ）. However, when coating concentration is 0. 5% , a minimum diffusion coefficient 0. 89 × 10^10（cm^2· s^-1） of water could be achieved.