Study On The Preparation, Characteration And Intercalation Mechanism Of Kaolinite-organic Intercalation Compouds

Kaolinite is a kind of1:1lamellar silicates, and its organic intercalationcompound has specific adsorption, dispersion, rheology, porosity and surface aciditywhich are characterized by clay mineral. And it also includes activity of functionalgroups of intercalated molecules. As a new type of materials, kaolinite intercalationcompound has broad application prospects in the high-performance polymer matrixcompounds, high-performance organic nano-ceramics, non-linear optical materialsand functional materials.Current researches in the field of organic intercalation of kaolinite mainlyfocused on the prepa ration and structure ana lysis, whereas the intercalationmechanism is still unc lear. In this paper, the relatively pure intercalation compoundshave obtained on the basis of studying the influences on the characterization ofunintercalation kaolinite and adsorbed intercalator. Furthermore, the paper alsoexplored the structure and kinetics of deintercalation reaction of intercaltioncompound, speculated intercalation mechanism and ensured the validity by Real-timeMonitoring Technic. The theoretical basis will be provided for the subsequentpreparation of polymer intercalation compounds.The kaolinite with DMSO, formamide, acetamide, benzamide intercalationcompounds were prepared by suspension method and secondary melting substitutionmethod. The basal spacing d001of kaolinite are increased from0.720nm to1.123nm,1.013nm,1.102nm and1.428nm respectively for the intercalation of organicmolecules. The respective intercalation rate are99%and78%,61%and82%.Intercalated molecules bonded with the kaolinite interlayer surface and arrangedorderly after inserting into kaolinite interlayer space.The adsorbed intercalators and unintercalation kaolinite will impact the IRspectra characterization in intercalation compound system. To choose an appropriateeluent will remove the adsorbed intercalator without destroying the structure of thecompound effectively, thereby to eliminate the impact of the adsorbed intercalators inthe system. The unintercalation kaolinite will impact the FTIR greatly in thecompound system when low intercalation rate, b ut not when the intercalation rate over80%.The intercalators which are polar organic amide derivative molecules of protonactivity were selected and the structures of FA, Ac, BZ intercalation compounds were studied systematically in the paper. The results showed that the FA, Ac, BZ moleculesfaced to the alumina octahedral surface of kaolinite with NH2and arranged nearlyperpendicular to the layer and orderly after they inserted into kaolinite. The insertingdestroyed the hydrogen bond of the original kaolinite, and formed a new hydrogenbond with the inner surface hydroxyl through NH2of intercalators.Kaolinite/FA, Ac, BZ intercalation compounds occured two-step decompositionin the temperature programmed process. The former step is deintercalation ofintercalator and the latter is the process of kaolinite dehydroxylation. The threecompounds are deintercalation occurred at about152,180,211℃and the weight lossrate are5.93%,6.70%and21.19%. The compounds deintercalation reactionactivation energy is equal roughl y and have the same reaction mechanism which isnth-order chemical reaction after kinetics calculating.The paper speculated the intercalation process contains two steps on the basis ofstudying structure and deintercalation of kaolinite/FA, Ac, BZ compounds. The firstis the diffusion process of the intercalators into the kaolinite interlayer which iscontrolled by the size of the intercalators. The next is chemical reaction betweenintercalators and kaolinite interlayer surface, which is controlled by the functionalgroups of intercalators. Real-time monitoring BZ intercalation into kaolinitediscovered that the intercalation includes three processes: activation, replacement,adjustment, which could confirm the previous inference.There are73figures,24tables and160reference articles in this paper..