蒙脱土的改性及其悬浮液的流变行为∗

摘要

Four small molecular compounds which could occur non-covalent interactions with montmorillonite (hexadecyl trimethyl ammonium bromide,CTAB,sodium dodecyl sulfate,SDS,4-aminobutyric acid,AA and Octa-quaternary ammonium silsesquioxane,Poss),two small molecular compounds which could occur covalent interactions with montmorillonite (1,3-propanesultone,PS and 3-aminopropyltriethoxysilane,KH550)and three polymer (Polyethylenimine,PEI,poly(acrylamide-co-diallyldimethylammonium chloride),PAADDA and quaternary ammonium polyethylenimine,QPEI)were used to modify montmorillonite.Fourier transform infra-red spectroscopy,X-ray diffraction,thermogravimetric analysis and laser particle size analyzer were employed to investigate modified montmorillonites.And rheological behaviors of suspensions consisted of modified mont-morillonite and styrene and 4-chloromethylstyrene copolymer in N,N′-dimethylacetamide also were studied. The results showed that the silicate layer spacing of all modified montmorillonites have been broadened and the layer spacing of the modified montmorillonite with QPEI was up to 2.41 nm.The stronger the hydrophobicity of montmorillonites modified by small molecular compounds was,the higher the Zeta potential of the correspond-ing montmorillonite was.The zeta potential of the modified montmorillonite with CTAB increased from-38.5 mV to 31.2 mV.The suspensions containing modified montmorillonites demonstrated a behavior of non-Newtonian fluid and revealed a slight viscosity reduction in the high shear rate region,the viscosity of suspen-sions containing the modified montmorillonite with QPEI increased about 40%.%4种可与蒙脱土进行非共价作用的小分子化合物(十六烷基三甲基溴化铵,CTAB、十二烷基硫酸钠, SDS、4-氨基丁酸,AA和八季铵基笼型聚倍半硅氧烷,Poss)、两种可与蒙脱土进行共价作用的小分子化合物(1,3-丙烷磺内酯,PS和γ-氨丙基三乙氧基硅烷,KH550)和3种聚合物大分子(聚乙烯亚胺,PEI、二甲基二烯丙基氯化铵-丙烯酰胺共聚物,PAADDA 和季铵化聚乙烯亚胺,QPEI)被用来改性钠基蒙脱土.采用傅里叶变换红外光谱、X射线衍射仪、热重分析仪和激光粒度仪对改性蒙脱土进行了表征,并测试了改性蒙脱土与对氯甲基苯乙烯-苯乙烯共聚物的N,N′-二甲基乙酰胺悬浮液的流变行为.结果表明,所有的改性蒙脱土的层间距都有所增加,其中QPEI改性蒙脱土的层间距达到2．41 nm；小分子改性的蒙脱土疏水性越强,Zeta 电位就越高,其中 CTAB 改性蒙脱土的Zeta电位由－38．5 mV增加至31．2 mV；添加改性蒙脱土的悬浮液呈现非牛顿流体行为,在高剪切速率区显示弱剪切变稀现象,其中含 QPEI改性蒙脱土的悬浮液粘度增加达40％以上.