Deintercalation Thermal Analysis Kinetics Of Kalinite Organic Intercalation Compounds

Research on kaolinite intercalation nanocomposite has become a new field of material which is full of vitality. However, due to the special layer structure of kaolinite, the intercalation of organic molecules is difficult to achieve. The present studies of kaolinite intercalation compounds basically focus on the preparation and structural characterization of the compounds,while the quantitative studies on the mechanism of the intercalation system is very few. In this paper, DMSO, formamide, acetamide were selected as the intercalation agents to prepared the corresponding kaolinite organic intercalation compounds. The structure and performance of the compounds were characterized by X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), Thermogravimetric-Differential Scanning Calorimetry analysis(TG-DSC).Moreover, thermal analysis kinetics of the deintercalation reaction of the compounds were investigated by different methods.In this paper, different thermal analysis kinetics methods were used to calculate the kinetics three factors of the deintercalation reaction: Ozawa method, KAS method, Ozawa-iterative method and KAS-iterative method were respectively used to calculate activation energy Ea;Satava method and Malek method were respectively used to determine the most probable mechanism function; Dollimore method and Friedman method were respectively used to calculated the pre-exponential factor A. The universality of thermal analysis kinetics methods applied in the deintercalation process of kaolinite intercalation compounds was investigated via calculation and comparative analysis, and the deintercalation reaction mechanisms were revealed. While the investigation of thermal analysis kinetic provided a basis for studying the mechanism of the intercalation. Main conclusions of this paper are as follows:(1) The deintercalation mechanisms of kaolinite/DMSO, kaolinite/formamide and kaolinite/acetamide intercalation compounds determined by different methods are the same,which is the NO.43 mechanism, n-level chemical reaction:)1/(])1(1[)(1n Gn---(28)-??,nf-(28)??)1()(.(2) For each intercalation compound, the Ea values of deintercalation reaction caculated by different methods are basically unanimous. The final Ea result is aimed at the average value caculated by KAS-Iteration method, KAS-Iteration method and Starink method are respectivelly84.09 k J/mol, 79.71 k J/mol, 86.97 k J/mol.(3) The A values range of the above-mentioned three inerecalation compound deintercalation reactions caculated by Friedman method are respectively 0.42 ×108~10.37×108,1.31×107~11.49×107, 1.02×108~9.54×108. The A values range caculated by Dollimore methodare respectively0.43×108~10.08×108, 1.60 ×107~9.87×107, 2.45 ×108~9.68×108. The magnitude of A calculated by these two method are the same, the value ranges are approximately consistent.(4) The deintercalation reaction activation energy Ea and pre-exponential factor A of each intercalation compound are respectlly different, Wherein the Ea and A of the deintercalation reaction of kaolinite/acetamide intercalation compound are the biggest, followed by kaolinite/DMSO. The Ea and A of the deintercalation reaction of kaolinite/formamide compound are the smallest. These Indicate that formamide and DMSO are easier to be intercalated into the inter-layer of kaolinite, while it is more difficult for acetamide to intercalate into kaolinite. The research of kaolinite organic intercalation compounds deintercalation reaction thermal analysis kinetic can provide a basis for studying the mechanism of intercalation.