Effect of alkylamine chain length on high-temperature phase transformation and thermal decomposition process of kaolinite intercalation compounds

摘要

The structural changes and thermal decomposition of kaolinite (Kaol) intercalation compounds during heating process limit their application in polymers which need to be heated during the preparation process. In this study, homologous compounds, namely, hexylamine (HEA) and octadecylamine (OCA), were used to intercalate Kaol to explore the effect of molecular chain length on the structural stability and thermal decomposition of intercalated compounds. After the intercalation by HEA and OCA, the expansion only occurred along the C-axis, and the basal spacing increased to 28.7 and 57.3 angstrom, respectively. The morphology of Kaol changed remarkably, and all appeared curly. Compared with Kaol/HEA intercalation compounds, the Kaol/OCA intercalation compounds had better curling effect due to their different molecular chain length. The thermal decomposition process of Kaol/alkylamine intercalation compounds can be divided into two distinct stages. The molecules that adhered to the surface of the nanoscrolls and existed in the lumen of nanoscrolls began to deintercalate in the first step, and the other molecules that intercalated Kaol layers began to decompose in the second step. Thus, Kaol can be used as a potential carrier material, a carrier of sustained-release drug, or a carrier material for the catalyst. The reaction is regulated by controlling the temperature of the reaction.