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以微晶纤维素(MCC)为基材,氯磺酸为磺化剂,二氯甲烷为分散剂,一步合成了磺化纤维素(CS)。采用FTIR1、3C NMR、SEM、XRD等分析手段对产品结构进行了表征,并考察了MCC聚合度、原料配合比、反应温度、反应时间等工艺参数对CS减水剂减水性能的影响。通过研究CS-水溶液的表面张力和CS-水-水泥体系的ζ电位,揭示了CS减水剂的减水机理。并采用SEM,对掺加CS的水泥材料的硬化过程进行了研究。结果表明:CS水溶液的表面张力随着CS减水剂浓度的增加而降低,它们在气-液界面的取向能力大,对混凝土有一定的引气作用;CS减水剂在水泥颗粒表面吸附的结果,使水泥颗粒表面带有相同电荷而相互排斥造成水泥颗粒的分散,从而出现减水效果;CS对水泥具有缓凝作用,由于缓凝作用,水泥初期水化反应发展缓慢,而经较长时间后,硬化水泥结构比基准样密实。
Using microcrystalline cellulose (MCC) as substrate, chlorosulfonic acid as sulfonating agent and dichloromethane as dispersing agent, sulfonated cellulose (CS) was synthesized in one step. The structure of the product was characterized by means of FTIR1, 3C NMR, SEM and XRD. The influence of technological parameters such as polymerization degree of MCC, raw material mix, reaction temperature and reaction time on water reducing performance of CS water reducer was also investigated. By studying the surface tension of CS-aqueous solution and the zeta potential of CS-water-cement system, the water-reducing mechanism of CS water-reducer was revealed. Using SEM, the hardening process of CS-containing cement materials was studied. The results show that the surface tension of CS aqueous solution decreases with the increase of concentration of CS water reducer, and their orientation ability at gas-liquid interface is large, and the air entrainment of concrete is certain. The effect of CS superplasticizer adsorbed on the surface of cement particles As a result, the surface of cement particles with the same charge and repel each other to cause the dispersion of cement particles, resulting in water reducing effect; CS has retarding effect on cement, due to retarding effect, cement hydration reaction slow development, After the time, hardened cement structure dense than the standard sample.