Thermal degradation of montmorillonite/aliphatic amine complexes in nitrogen

Montmorillonite (Mont)/aliphatic amine complexes were synthesized using five kinds of aliphatic amine (C₂–C₁₈) hydrochlorides, and their thermal degradation below 1473 K in nitrogen was examined. Raw Mont was used as a reference. The interlayer spacings of the complexes were roughly proportional to the size of amine molecules. The five complexes showed almost the same degradation mode. All the guest amines were released from the host Mont at between 573 and 673 K without any carbon remaining, but their interlayer spacings decreased gradually up to 873 K. The layer structures of Mont and complexes were destroyed just below 1273 K. After destruction, an amorphous phase formed in Mont but not in the complexes. After heating to high temperatures, the crystals deposited in Mont were not necessarily identical to those in the complexes and these differences are attributable to the sodium content.