聚丙烯酸酯乳液改性砂浆微观结构与改性机理

为了研究聚丙烯酸酯乳液（PA）改性砂浆硬化过程中微观结构的形成过程及改性机理,分析PA聚合物乳液在新拌水泥砂浆中的吸附特性,并模拟孔隙溶液和PA乳液之间相互作用.同时采用扫描电子显微镜（SEM）和能谱分析（EDX）法表征了PA改性砂浆微观结构的演化过程.试验结果表明,PA颗粒将与孔隙溶液中的钙离子发生化学反应,PA聚合物将以不同的形态吸附在水泥砂浆的局部部位.在此基础上,考虑PA聚合物改性乳液与水泥基材料的反应,提出一种改进的聚合物改性与微观结构形成模型.这对研究聚合物改性水泥基材料的力学性能与推广聚合物改性水泥基材料在工程中的应用具有重要意义.

Microstructure and modification mechanism of polyacrylate latex modified mortars

In order to study the microstructure forming process and modification mechanism of polyacrylate (PA) latex modified mortars during the hardening process, the adsorption performance of PA latex in fresh mortars was analyzed, and the interaction between PA latex and pore solution was simulated. Meanwhile, the microstructure evolution of PA modified mortars was measured by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Detector (EDX) analysis. The test results show that PA particles chemically react with calcium ions in the pore solution and PA polymer is localized at some places within cement mortar through different morphologies. Based on these experiments, in considering the reactions between PA latex and cement-based materials, an improved polymer modification and microstructure formation model is proposed. This is of great importance for the investigation on the mechanical properties of polymer modified cement-based materials and the application of polymer modified cement-based materials in civil engineering.