交联型酯类聚羧酸减水剂的制备及研究

Preparation and study on crosslinking type esters polycarboxylate superplasticizer

根据分子结构设计原理,采用MPEG与MAA进行酯化制备MPEGMAA,并在相同条件下,利用制备酯化大单体中过量的MAA与烯丙醇继续酯化,即得到含交联单体甲基丙烯酸烯丙酯的酯化大单体MP,并在引发剂、链转移剂和单体作用下进行自由基聚合反应,合成一种交联型酯类聚羧酸减水剂PC-2,初步探讨了不同分子质量MPEG的比例、酸醇比、丙烯基亚磷酸酯用量和反应浓度等对减水剂分散性和分散保持性的影响,采用凝胶渗透色谱对聚合物的分子质量和分子质量分布进行表征。实验结果表明:该减水剂的最佳制备工艺为:n(MAA)∶n(MPEG)=5∶1,n(MPEG-600)∶n(MPEG-2200)=1∶1,反应体系浓度为40%,丙烯基亚磷酸酯和甲基丙烯磺酸钠用量分别为酯化大单体总质量的3.5%和2%。经测试验证,该减水剂PC-2的减水率、坍落度保持性和增强效果都明显优于常规酯类聚羧酸PC-1。

According to the molecular structure design principle,use MPEG and MAA ester to prepare MPEGMAA,and under the same conditions,use excess MAA of preparation of esterified macromere go on esterification with allylalcohol,then get esterified macromere （MP） contains erosslinking monomer allyl methaerylate and carried out free radical polymerization response by initiator, chain transfer agent and monomer. A crosslinking type esters polycarboxylate superplastieizer superplasticizer PC-2 was synthesized after the above steps. The iniluenee of proportion,acid alcohol ratio,propylene based pht）sphorous acid and the concentration of reaction of different molecular weight preliminary on dispersibility on water reducing agent,dispersed retention were discussed. Polymer molecular weight and molecular weight distribution were also characterized by the gel permeation chromatography （GPC）. The experimental result showed that the water reducing agent had a optimized preparation condition at n （MAA）：n（MPEG）=5：1,n（MPEG- 600）：n（MPEG-2200）=1：1,reactian system concentration was 40%,the dosage of propylene based phosphorous acid and sodium methallyl sulfonate was 3.5% and 2% of total mass respectively. The water-reducing rate, slump retention and reinforcing effects were all better than regular polycarboxylate PC-1 by eases testing.