星-梳形聚羧酸减水剂的合成及其对水泥基材料表观粘度的影响

摘要

通过含有多个巯基基团的星形链转移剂调控下的自由基聚合,制备了一系列分子质量不同的星-梳形聚羧酸减水剂聚丙烯酸-co-聚(异丁烯醇聚氧乙烯醚)(PAA-co-PIPEG).采用核磁共振仪和带三重检测器的凝胶渗透色谱仪表征了制备的聚羧酸减水剂的分子结构.通过净浆、吸附、流变和混凝土试验研究了星-梳形聚羧酸减水剂对水泥基材料性能的影响.结果表明,星-梳形结构会降低聚羧酸减水剂的减水能力和吸附效率,但同时也会显著降低水泥基材料的表观粘度.%A series of star-comb copolymer architecture of polycarboxylate superplasticizers,poly (acrylic acid)-co-poly[isoprenyl oxy poly(ethylene glycol)ether](PAA-co-PIPEG)with different molecular weight,were prepared by free radical polymerization under the adjustment of a star chain transfer agent with multiple sulfhydryl groups. The molecular architecture of the star-comb polycarboxylate was characterized by proton nuclear magnetic resonance and gel permeation chromatography with a triple-detector system. The effects of the star-comb polycarboxylate superplasticizers on cement-based materials were investigated by net fluid,adsorption,rheology and concrete experiments. It was found the star-comb structure weakened the water-reducing ability and adsorption efficiency of polycar-boxylate superplasticizers,but at the same time significantly reduced the apparent viscosity of cement-based materials.