改善废水污泥基外墙涂料透水性的研究

采用废水污泥制备建筑外墙涂料,探讨了石蜡乳液、防水剂、烷基烯酮二聚体(AKD)、丙烯酸酯乳液、绢云母粉和搅拌时间对污泥涂料透水性的影响。结果表明:在防水剂用量3.03%、石蜡乳液用量1.19%、聚丙烯酸酯乳液用量22.70%、绢云母粉用量3.79%和调漆阶段搅拌时间40 min时,污泥涂料的透水性为0.4 mL/24 h,达到了国家标准GB/T 9755—2014对透水性要求;AKD乳液虽可有效降低涂膜吸水率,但与污泥涂料体系中其他组分的相容性差,不宜作为防水组分应用于所研究的涂料体系;适当延长调漆时间,可降低污泥粒子中位径使涂膜较为紧密从而提高涂料抗透水性;污泥涂料膜表面有类似荷叶的乳突状结构,其抗透水能力优于实验中的市售涂料。

Study on Water Permeability of Exterior Wall Coatings Based on Wastewater Sludge

A kind of exterior wall coating based on wastewater sludge was prepared. The effects of addition of paraffin emulsion, waterproof agent, alkyl ketene dimer (AKD), acrylate emulsion, sericite powder and mixing time on the water permeability of the prepared coatings were studied. The results showed that the water permeability of the coating was 0.4 mL/24 h, being in line with the the permeability requirements as described in GB/T 9755—2014 when the amount of the waterproofing agent was 3.03%, the paraffin emulsion was 1.19%, the polyacrylate emulsion was 22.70%, the sericite powder was 3.79%, and the stirring time was 40 min. AKD emulsion could effectively reduce the film water absorption but has a weak compatibility with the coating system, which was not suitable for a waterproof component used in the coating system. Appropriate extension of mixing time could reduce the sludge particle size in coatings so as to make the coating denser conducive for the improvement of resistance to water permeability. The surface of the sludge coating had a papillary structure similar to that of the lotus leaf, which enables it to show superior performance to the commercially available paints involved in this experiment.