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通过共沉淀法将萘系减水剂插入MgAl-LDH层间制得一种缓释型萘系减水剂。通过XRD、IR对插层产物进行了分析,用紫外分光光度计对插层产物的缓释性能及缓释机理进行了考察。结果表明:萘系减水剂插层后,MgAl-LDH的XRD特征衍射峰向小角度移动,层间距从原来的0.76 nm增大到1.06 nm;红外图谱在1 035.6和1 123.1 cm-1处出现了萘系减水剂中—SO3基团的吸收峰,且MgAl-LDH中NO3-基团的吸收峰明显减弱;由此说明萘系减水剂已经进入了MgAl-LDH层间。在H2O和Na2CO3中考察了其缓释性能和机理,结果表明,产物具有明显的缓释性能,且释放速率较大的初期符合一级动力学方程,其缓释机理主要为客体阴离子与介质中CO32-的离子交换过程。水泥净浆流动度测试表明,相比商品萘系减水剂,它有明显的缓释效果。
By co-precipitation naphthalene superplasticizer inserted between MgAl-LDH layer to prepare a sustained-release naphthalene superplasticizer. The intercalation products were analyzed by XRD and IR. The sustained release properties and sustained release mechanism of the intercalation products were investigated by UV spectrophotometer. The results show that the XRD characteristic diffraction peak of MgAl-LDH moves to a small angle after intercalation with naphthalene superplasticizer, and the interlayer spacing increases from 0.76 nm to 1.06 nm. The IR spectra at 1 035.6 and 1 123.1 cm-1 The absorption peak of -SO3 group in the naphthalene superplasticizer appeared, and the absorption peak of NO3- group in MgAl-LDH obviously decreased. Thus, the naphthalene superplasticizer had entered the layer of MgAl-LDH. The sustained-release properties and mechanism of the product were investigated in H2O and Na2CO3. The results showed that the product had obvious sustained-release properties, and the initial release rate of the product was in good agreement with the first-order kinetics equation. The slow- CO32- ion exchange process. Cement paste fluidity test showed that compared to commercial naphthalene superplasticizer, it has a significant sustained release effect.