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通过乳液聚合制备了表面性质不同的两种阴离子乳液,即C4与CT乳液。C4乳液在制备过程中通过共聚甲基丙烯酸(MAA)使其中聚合物乳液粒子表面带负电荷,而CT乳液不仅共聚相同量的MAA单体,同时在合成中通过共聚异戊烯聚氧乙烯醚(TPEG),在乳液粒子表面引入非离子聚氧乙烯(PEO)毛梳层。通过水化热测试、颗粒表面电荷滴定、钙离子电极测试、等温吸附测试等实验探讨了两种乳液对水泥水化的影响及其内在机理。结果表明:与C4乳液相比,表面含非离子PEO毛梳层的CT乳液对水泥水化的抑制作用明显减弱;聚合物乳液粒子表面毛梳层不会降低羧基官能团对钙离子的络合能力;非离子PEO毛梳层的引入显著降低了聚合物乳液粒子在水泥颗粒表面的吸附量。两种乳液粒子在水泥颗粒表面吸附性能的差异是导致其对水泥水化不同影响的主要原因。
Two anionic emulsions with different surface properties were prepared by emulsion polymerization, namely C4 and CT emulsions. C4 emulsion in the preparation process by copolymerization of methacrylic acid (MAA) in which the surface of the polymer emulsion particles negative charge, and CT emulsion not only copolymerization of the same amount of MAA monomer, while in the synthesis by copolymerization of isopentenyl polyoxyethylene ether (TPEG), a non-ionic polyoxyethylene (PEO) wool comb layer was introduced on the surface of emulsion particles. The hydration heat test, particle surface charge titration, calcium ion electrode test and isothermal adsorption test were used to investigate the effects of two emulsions on cement hydration and its intrinsic mechanism. The results showed that the CT emulsion with nonionic PEO combs on the surface significantly reduced the hydration of cement compared with that of C4 emulsion. The hair combs on the surface of polymer latex particles did not decrease the complexation ability of carboxyl functional groups to calcium ions The introduction of non-ionic PEO wool comb layer significantly reduced the adsorption amount of polymer emulsion particles on the surface of cement particles. The difference of the adsorption properties of two kinds of emulsion particles on the surface of cement particles is the main reason that causes different effects on the cement hydration.