| Intercalation reaction has been well known as one of the significant method for forming inorganic-organic nanocomposites under mild conditions. Kaolinite is a major host materials for the intercalation reaction. Kaolinite-organic intercalation has an important signification for researching the kaolinite structure and understanding reaction mechanism between natural organic matters and minerals. Kaolinite-organic intercalation compound possesses not only the unique adsorptivity,dispersivity. porosity,rheological behaviour and surface acidity of the clay mineral but also the multivariate functional groups and the reactivity of the organic compound. As a new type of mineral materials,it has extensive potential application in catalysts,functional supporter,adsorbents and advance ceramics. In this paper,the kaolinite/polyacrylamide intercalation compound was prepared first by the displacement reaction of kaolinite/formamide intercalation precursor with acrylamide,and then the in-situ polymerization of acrylamide. The kaolinite structure and the intercalation mechanism were discussed by the techniques of powder X-ray diffraction analysis,*H MAS NMR,Raman,and IR spectra. The employ kaolinite/polyacrylamide intercalation compound as a raw material to in-situ synthesize Sialon was test by the carbothermal reduction and simultaneous nitridation (CRSN) technique.This work was supported by the National Natural Science Foundation of China (Grant No. 40072014),the Natural Science Foundation of Guangdong Province(GrantNo. 010496) and the Foundation of State Key Laboratory for Physical Chemistry of Solid Surfaces in Xiamen University (Grant No. 9911). Main conclusions of this work are drawn as follows:1) The influence factors on the kaolinite/formamide intercalation reaction have been made a systematic study. The results show that the kaolinite with low structure order degree and relative large particle size is more easily intercalated under well dispersed. The intercalation reaction is very sensitive to moisture and a small amount of water added to the kaolinite-formamide system facilitates the intercalation reaction. The optimum water content 5--9%(V/V) was found. Under these conditions,an intercalation compound with intercalation ratio of 96% was obtained. The compound formula,Al2Si2O5(OH)4(HCONH2)o.5,can be calculated from the TG datd. The guest displacement reaction of kaolinite/formamide intercalation compound with acrylamide is affected by the type of solvent and the content of acrylamide. The polymerization of acrylamide in kaolinite interlayer mainly controlled by the polymerization temperature. The kaolinite/polyacrylamide compound with the polymerization intercalation ratio of 88%0 was obtained and the compound formula,(Al2Si2O5(OH)4-4CH2CHCONH2-)-o.736),can be calculated from TG data.2) The proton chemical shifts of the two surface hydroxyl groups of kaolinite were successfully identified with the high spinning speed JH magic angle spinning nuclear magnetic resonance ('H MAS NMR) technique. The proton chemical shifts of the inner hydroxyl and inner surface hydroxyl of kaolinite are in the range of 5-1.3-0.9 and 82.4-3.0 respectively. After formamide intercalation,three proton peaks were detected. The proton peak of the inner surface hydroxyl of the intercalation compound shifts to high-field with 52.3-2.7,whereas the proton peak of the inner hydroxyl shifts to 5-0.3 toward low-field. The third proton peak is in the range of 55.4-5.6 that belonged to the ami no group of formamide. The stability of the three protons of intercalation compound is in the order of amino group proton > inner surface hydroxyl proton inner hydroxyl proton.3) Raman and IR spectroscopy techniques have been used to study kaolinite-organic intercalation mechanism. During the intercalation reaction,the original hydrogen bonds between the Al(O,OH)(,octahedral hydroxyl groups and the SiO4 tetrahedral oxygens were broken,and the new hydrogen bonds between organic molecular and kaolinite were formed. One is the C=O groups of fo...
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