Differential thermal analysis of montmorillonite

Preparation and characterization of novel clay/PLA nanocomposites

“…7, B and D). This is consistent with published results which indicate that modification by an organic cation can effectuate the loss of surface adsorbed water at lower temperatures, owing to the decrease in the hydrophilicity of the mineral surface (Fajnor and Jesenak, 1996). Moreover, due to the decrease in hydrophilicity, the amount of adsorbed water lost is lower than that of starting clay (Volzone and Garrido, 2012).…”

“…The dehydroxylation of BRN, centered at 472°C, was lower than that of SWy-2, centered at 652°C. Factors affecting the dehydroxylation of montmorillonite would include the type of exchangeable cation (Mackenzie and Bishui, 1958) and on the presence of iron ions in the mineral structure (Masár et al, 1987;Fajnor and Jesenak, 1996). It was interpreted that the thermal events associated with the illite and kaolinite that are concurrently present in the BRN sample may have overlapped with those of smectite and were thus indistinguishable by TGA analysis.…”

Hydration of a Na+-montmorillonite studied by thermally stimulated depolarization current

“…Differential scanning calorimetry signal, reported in Fig. 2, gives two endothermic peaks, which correspond to the loss of water located in the interlayer space at 105 • C and to dehydroxylation at 638 • C [17]. This demonstrates the thermal behavior of our sample can be interpreted as the corresponding one of a montmorillonite.…”

Pozzolanic reactivity of a calcined interstratified illite/smectite (70/30) clay

“…For heat treatment above 1000°C, the Q 4 -type silica is dominant and the structure is stable up to at least 1100°C, the maximum calcination temperature used in this work. This thermal transformation sequence involving dehydration, dehydroxylation, amorphization, and finally recrystallization has been reported for several 2:1 type clay minerals using tools like solid-state NMR [16,[33][34][35][36], thermal analysis [37], a combination of EPR, XRD, SEM [38] and TEM [39]. The studied mixedlayer illite/smectite clay also follows such a transformation scheme, and thus it is expected that its pozzolanic behavior as function of calcination temperature will be similar to that recently reported for a pure montmorillonite [16].…”