可再分散乳胶粉耐水性能改进初探

以醋酸乙烯(VAc)、丙烯酸(AA)和C4等作为共聚单体,以保护胶体B4(普通型)或A3(特殊型)作为改性剂,采用高速离心喷雾干燥法制备可再分散乳胶粉。将该胶粉作为砂浆的改性剂,通过对比试验优选出较适宜的保护胶体。结果表明:采用A3制备的胶粉具有良好的可再分散性、成膜性(干、湿膜拉伸强度分别为28.1、3.6 MPa,干、湿膜的断裂伸长率分别为315.8%、109.2%)和耐水性,由其配制而成的聚合物改性砂浆具有相对较低的吸水量(A3体系的吸水量比B4体系降低了64.4%)。

Preliminary study on improving water resistance of re-dispersible emulsion powder

With vinyl acetate(VAc),acrylic acid(AA) and C4 as comonomers,and with protective colloid B4(ordinary type) or protective colloid A3(special type) as modifiers respectively,a re-dispersible emulsion powder was prepared by high-speed centrifugal spray dryness.Then with the re-dispersible emulsion powder as the modifier of cement mortar,the appropriate protective colloid was selected by contrast experiment.The results showed that the re-dispersible emulsion powder with A3 had good re-dispersible property,film forming ability(dry or wet tensile strength at 28.1 MPa or 3.6 MPa,dry or wet ultimate elongation at 315.8% or 109.2%) and water resistance.And the cement mortar modified by polymer,which was made from re-dispersible emulsion powder with A3,had relatively lower water absorption because the water absorption of A3 system was 64.4% lower than that of B4 system.