## 3 Results
### Infrared Study  
Infrared spectra of ODTMA-clay and BDMHDA-clay samples are shown in Figures 3 and 4, respectively. The peak observed at 3628 cm\({}^{-1}\) is related to structural water (Figure 3a). No change in this peak was observed (Figure 3b). Thus, after MW heating the structural water between the clay layers was not affected and the layers did not collapse. The weak peak observed at 3411 cm\({}^{-1}\) is related to the absorbed water (stretching vibrations) (Figure 3a). This highly weakened peak represents the hydrophobic structure of the organo-clay resulting from the interaction of the surfactant molecules with the clay. This interaction is described as the interlocking of the siloxane layer of the clay and surfactant methyl group [18]. The spectral profile region changes significantly with the concentration of surfactant molecules in the 3000 to 3550 cm\({}^{-1}\) range [19]. The intensity of this band decreases with surfactant concentration and is attributed to water hydrating the cation in the clay interlayer [19]. The very low peak intensity observed at 3411 cm\({}^{-1}\) is due to the high concentration of ODTMA in the organo-clay. In addition, the wavenumber of antisymmetric CH\({}_{2}\) stretching mode is sensitive to the \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{3}{c}{**ODTMA Br**} & \multicolumn{5}{c}{**BDMHDA Cl**} \\ \hline
**Time (min)** & **Mass g** & **Time (min)** & **Mass g** & **Time (min)** & **Mass g** & **Time (min)** & **Mass g** \\ \hline
0 & 78.5 & 11 & 47.6 & 0 & 78.5 & 11 & 50.1 \\
2 & 74.3 & 12 & 45.0 & 2 & 74.5 & 12 & 47.1 \\
4 & 69.5 & 13 & 42.5 & 4 & 70.6 & 14 & 44.7 \\
6 & 63.7 & 14 & 41.1 & 6 & 64.6 & 16 & 42.9 \\
8 & 57.5 & 15 & 40.7 & 8 & 58.2 & 17 & 41.5 \\
10 & 50.7 & 16 & 40.2 & 10 & 52.7 & 18 & 41.0 \\ \hline \hline \end{tabular}  
* Conditions as in Table 1.  
\end{table} 
Table 2: Drying in MW oven: Granules included ODTMBr or BDMHDACI a. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Humidity [\%]** & **Heating Time [min]** & **Sample Mass [g]** & **Temp [\({}^{\circ}\)C]** & **Remark** \\ \hline
5 & 0 & 27.4 & 26 & \\
5 & 2 & 24.3 & \textgreater{}100 & Material was \\
20 & 0 & 32.5 & 26 & \textgreater{}100 \\
20 & 2 & 26.6 & 88 & Material was \\
40 & 0 & 43.3 & 26 & \textgreater{}100 \\
40 & 2 & 34.3 & 85 & \\
40 & 3 & 29.7 & 88 & \\
40 & 4 & 26.6 & 98 & \\ \hline \hline \end{tabular}  
* The standard error of each mass was less than 0.3 g.  
\end{table} 
Table 3: Heating of granules (ODTMA–clay) which included different water percentages in a MW oven (700 W) for several durations: removal of water and elevation of temperature of granules a.  
conformational change of amines within the clay interlayer [19]. This peak was observed at 2917 cm\({}^{-1}\) for the ODTMA-clay sample, whereas it was observed at 2921 cm\({}^{-1}\) for the BDMHDA-clay sample (Figure 4). The different adsorbed water behaviors in both organo-clays (ODTMA and BDMHDA) are attributed to the difference in concentrations of organic cations, or surface interaction mechanisms. This peak disappeared after MW heating. Therefore, a small amount of adsorbed water in the organo-clay was removed from the samples by MW heating. The peaks observed at 2917 cm\({}^{-1}\) (asymmetric) and 2849 cm\({}^{-1}\) (symmetric) are related to the C-H stretching vibrations. In these peaks small changes were observed with MW heating. The peak observed at 1642 cm\({}^{-1}\) represents the bending vibration of adsorbed water. This peak may originate from residual water molecules between the ODTMA ion layers as mentioned previously [16]. This peak was weakened upon MW heating (Figure 3b). The Sharp peak at 1012 cm\({}^{-1}\) is due to Si-O stretching. Small changes in this peak were observed. It was indicated that the CH\({}_{2}\)-stretching vibration of amine chains was very sensitive to the conformational ordering of the chains [20].