Analysis On The Interlayer Structure Of Intercalated Vermiculite And The Preparation Of Its Hydrosol

Vermiculite can be used to increase the properties such as fireproof and heat insulation. Organic vermiculite was prepared by the reaction of native vermiculite through intercalation with organic quaternary ammonium salts with different length of carbon chain in aqueous solution. Then dispersants of different structures were added into organic vermiculite,and milled into small particles for the preparation of vermiculite hydrosol.The organic vermiculite was characterized by X-ray diffraction(XRD),thermo gravity analyzer(TGA),and infrared spectroscopy(FT-IR).The results revealed that the tetramethylammonium bromide with carbon chain(G₄TA-Br)cannot enlarge the interlayer spacing of vermiculite while others can.There is distinct effect;native vermiculite is arranged orderly and closely before reaction;while it is intercalated by organic quaternary ammonium salts (C₁₂TA-Cl,C₁₆TA-Br,C₂₂TA-Cl and C₃₆TA-Cl).the layers are swelled.The interplanar crystal spacing of vermiculite increased distinctly,but the arrangement of layers is still orderly.The interlayer spacing of intercalated vermiculite was enlarged with the increase of the length of carbon chain from 1.49nm to 5.66nm,and the longer the length,the larger of the interlayer spacing was.The interlayer spacing 5.66nm of the intercalated vermiculite is the first obtained largest value in all the research of vermiculite. When the quantity of C₁₆TA-Br is added in solution of vermiculite step by step,the arrangement of C₁₆TA-Br in vermiculite interlayer have two models;paraffin type monolayer, paraffin type bilayer.The organic cations(C₁₂TA-Cl,C₂₂TA-Cl,and C₃₆TA-Cl)have enough potential energy to react with kalium cation of the phlogopite interlayer; the structure of phlogopite interlayer changed into vermiculite interlayers.With the increase of the stack density of C₁₂TA-Cl,C₂₂TA-Cl and C₃₆TA-Cl,the change of the arrangement of organic cations can be summarized as the following;paraffin type bilayer in vermiculite,paraffin type bilayer both in vermiculite and phlogopite.Stable vermiculite hydrosol was prepared by introducing dispersants by the first time in this paper.Nine kinds of dispersants were used in this research.The properties of vermiculite hydrosols were studied using laser particle size analyzer,gravity settling,transmission electron microscope(TEM)and Tyndall phenomenon analyzer.Results showed that several satisfying hydrosols can be stable for 60 days plus by using surfactant dispersants and organic polymeric dispersants.The surfactant dispersants;sodium dodecyl sulfate and sodium dodecylbenzene sulfonate have hydrophobic carbon chains,which could bond with the carbon chains of organic vermiculite.In this way,the hydrophilic sulfonic groups will expose to the exterior of the vermiculite particles.The long carbon chain organic ammonium salts(C₂₂TA-Cl,and C₃₆TA-Cl) could combine with the long chain of organic polymeric dispersants,whose effect could decrease the surface tension to keep the hydrosol system stable.Results also showed that 50% of the particle size in the hydrosols cast the range from 0.5um to 1.0μm...