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用尿素法制备了镁铝层状双金属氢氧化物(MgAl–layered double hydroxide–likehostmaterials,MgAl–LDHs),采用焙烧复原法将商品萘系减水剂插入MgAl–LDHs的层间,得到了一种缓释型萘系高效减水剂。采用热重–同步差热分析、X射线衍射和红外光谱分别对MgAl–LDHs、焙烧后的镁铝层状双金属氧化物(magnesium aluminum layered double oxide,MgAl–LDO)和用萘系减水剂插层MgAl–LDHs的产物等的结构进行了表征,分析了不同焙烧温度对插层组装效果的影响,并测试了掺此种减水剂的水泥净浆流动度的经时变化。结果表明:在500℃焙烧得到的MgAl–LDO,其层状结构可以恢复。萘系减水剂插层后,MgAl–LDHs的X射线衍射特征峰向小角度移动,层间距由原来的0.76nm增大到1.03nm;红外光谱在1035.6cm–1和1123.1cm–1处出现了萘系减水剂中SO3–基团的吸收峰,且MgAl–LDHs中NO3–基团的吸收峰明显减弱。与基准相比,此减水剂具有明显的减小水泥净浆流动度经时损失的效果。
MgAl-layered double hydroxide-like host materials (MgAl-LDHs) were prepared by urea method. The commercial naphthalene superplasticizer was inserted into MgAl-LDHs layers by roasting and recovery method, and a Long-term release of naphthalene superplasticizer. The effects of MgAl-LDHs, magnesium aluminum layered double oxide (MgAl-LDO) after calcination and the use of naphthalene superplasticizer The structure of intercalated MgAl-LDHs was characterized. The effect of calcination temperature on intercalation and assembly efficiency was analyzed. The change of cement paste fluidity with time was observed. The results show that the layered structure of MgAl-LDO calcined at 500 ℃ can be recovered. After intercalation of naphthalene superplasticizer, the characteristic peaks of X-ray diffraction of MgAl-LDHs moved to a small angle, and the interlayer spacing increased from 0.76nm to 1.03nm. The IR spectra appeared at 1035.6cm-1 and 1123.1cm-1 The naphthalene superplasticizer SO3- group absorption peak, and MgAl-LDHs NO3- group absorption peak was significantly reduced. Compared with the benchmark, this water reducer has the obvious effect of reducing the loss of cement paste fluidity over time.