聚羧酸减水剂分子量和官能团比例对其分散性能的影响

作为新型高性能减水剂,聚羧酸减水剂优越的分散性能取决于其分子结构可设计性。该文以改性大单体TPEG、丙烯酸(AA)和马来酸酐(MAD)等单体为主要原料合成聚羧酸减水剂,通过Ft-IR和GPC表征减水剂分子量、官能团类型和比例,并探讨减水剂在水泥净浆和砂浆中的分散性能。结果表明,以-COOH官能团为主导的减水剂减水性能较好,保坍性能则较差;以一定比例的-COOH和-COOR组成的官能团为主导的减水剂保坍性能较好,初始减水性能较差。随着n(-COOH)/n(-COOR)的不断增大,减水剂减水性能逐渐变差,保坍性能逐渐变好。

Effect of Molecular Weight and Functional Group Ratio of Polycarboxylate Superplasticizer on Its Dispersity

As a new type of high performance water-reduce admixture, the superior dispersity of polycarboxylate superplasticizer is based on the good design ability of molecular structure. In this article, polycarboxylate superplasticizer is synthesized by acrylic acid(AA), maleic anhydride(MAD) and methyl alkenyl polyoxyethylene polyoxypropylene ether(TPEG). The molecular weight and functional group are characterized by Ft-IR and GPC. The disparity is discussed by cement paste and mortar. The result shows that the functional group -COOH plays an important role on dispersive performance while -COOR majorly contributes to slump retaining. With the n(-COOH)/n(-COOR) gradually increases, the dispersive performance of polycarboxylate superplasticizer become better and the slump retaining becomes worse.