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Thermal Degradation Studies of Alkyl-Imidazolium Salts and Their Application in Nanocomposites



W H. Awad, Jeffrey W. Gilman, Marc R. Nyden, Richard H. Harris Jr., T E. Sutto, J H. Callahan, Paul C. Trulove, H X. DeLong


Increasing the thermal stability of organically modified layered silicates is one of the key points in the successful technical application of polymer layered-silicates nanocomposites on the industrial scale. To circumvent the detrimental effect of the lower thermal stability of alkyl ammonium treated montmorillonite, a series of alkyl imidazolium molten salts were prepared and characterized by thermal gravimetric ananlysis (TGA) and thermal desorption mass spectroscopic (TDMS). The effect of different parameters such as: counter ion, alkyl chain length and structural isomerism on the thermal stability of the imidazolium salts was investigaed. Alkyl imidazolium treated montmorillonite clays were prepared by ion exchange of the imidazolium salts with Na-montmorillonite. These organically modified clays were then characterized by XRD, TGA-FTIR and TDMS, and compared to the conventional quaternary alkyl ammonium montmorillonite. Results indicate that the counter ion has an effect on the thermal stability of the imidazolium salts, and that imidazolium salts with PF6, N(SO2CF3)2 and BF4 anions are thermally more stable than the halide salts. A relationship was observed between the chain length of the alkyl group and the thermo-oxidative stability; as the chain length increased from propyl, butyl, decyl, hexadecyl, octadecyl to eicosyl, the stability decreased. The results also show that the imidazolium treated montmorillonite has greater thermal stability as compared to the imidazolium halide. Analysis of the decomposition products by FTIR provides an insight about the decomposition products which are basically water, carbon dioxide and hydrocarbon.
Thermochimica Acta


Degradation, Imidazolium salts, Montmorillonite, Thermal stability


Awad, W. , Gilman, J. , Nyden, M. , Harris Jr., R. , Sutto, T. , Callahan, J. , Trulove, P. and DeLong, H. (2017), Thermal Degradation Studies of Alkyl-Imidazolium Salts and Their Application in Nanocomposites, Thermochimica Acta (Accessed April 20, 2024)
Created February 19, 2017