Characterization of hexadecyltrimethylammonium-organoclay and its individual components by thermal techniques

Abstract

The properties of the materials determine their potential applications. The aim of this article is to study the properties of the organoclays using simple and rapid technologies. Organoclays with different surfactant loadings (SL) were synthesized using an Argentine bentonite with a high content of montmorillonite (Bent) and hexadecyltrimethylammonium bromide as cationic surfactant. The samples were characterized using thermal techniques. The results revealed that the hydrophilicity of the organoclays decreases with increasing SL until the SL reaches 0.8 times the cation exchange capacity of the clay; and remains constant at a higher surfactant load. The stability of organoclays was inversely proportional to the SL of each sample. The layers showed a stabilization of approximately 40°C for their structural transformation temperature, caused by the presence of the surfactant. In addition, at a SL <1.0 the surfactant presented a ‘liquid-like’ structure in the interlayer space, whereas at a SL >1.0 the structure was ‘solid-like’.