一种环氧粉末涂层的吸水性研究

Water Absorption Behavior of a Kind of Epoxy Powder Coating

利用称重法对一种环氧粉末涂层在不同溶液种类(NaCl,KCl,CaCl2和蒸馏水),不同温度(20,40,60和80℃),不同浓度NaCl溶液中的吸水性进行了研究。结果表明,水在环氧粉末涂层中的扩散基本符合Fick第二定律,饱和吸水量和水在涂层中的扩散系数与溶液温度和水活性有关,并计算得到不同溶液中水在环氧粉末涂层自由膜中扩散的活化能;涂层浸泡过程中填料会有溶出,不同溶液溶出行为不一致;一次结合水和二次结合水含量随温度的升高而增大;80℃蒸馏水中涂层结构发生松弛导致吸水量不断增加。

The water absorption characteristics of a kind of epoxy powder coating in different type of solutions(NaCl,KCl,CaCl2,distilled water) at temperatures(20,40,60 and 80 ℃) were studied by mass gain measurement.Results showed that the diffusion of water in epoxy powder coating obeys the second Fick's law,while the saturated quantity of water absorption and diffusion coefficient of water in the coating is related with the solution temperature and water activity,fillers of the coating will be dissolved out during immersion,however the amount of the dissolved filler varies with the type of solution;the amount of the primary-and secondary-bound water increases with the rise of temperature.In the distilled water at 80 ℃ relaxation of the coating occurred leading to the enhancement of water absorption.Besides,the activation energy of water diffusion in epoxy powder coating was also calculated for different solutions.