A COMPARATIVE STUDY ON THE EFFECT OF DIFFERENT ALKYLAMMONIUM SALTS ON THE THERMAL AND SURFACE PROPERTIES OF ORGANICALLY MODIFIED CLAY

Organically modified clays (MNC) are credited with better reinforcing properties relative to other particulate fillers in polymer composite preparation. Apparently, this may be due to their high aspect ratio, packing fraction and surface area. However, thermal and surface properties of MNC are highly imperative as these determine the properties of the final polymer composite. The present paper reports the effect of surface modification on the thermal stability and surface properties of bentonite clay modified with selected alkyl-ammonium salts. Three different organically modified clays were prepared in the presence of dodecylamine (DDA), octadecylamine (OCT) and cetyltrimethyl ammonium bromide (CTA) as modifying agents. The clay morphological properties, surface characteristics, and thermal stability were studied by using FESEM/EDX, FTIR, XRD and TGA respectively. FESEM/EDX results show a clear distinction in the morphological properties and elemental composition of the clay samples with 7.27% carbon in OCT treated clay. FTIR spectra justified the results of FESEM/EDX showing multiple peaks that are indication of functional groups attachment on the clay surfaces. The resulting d-spacings determined from the wide angle X-ray diffraction (WAXD) patterns complement the results of FTIR and these are 4.36nm, 4.33nm, 4.14nm and 3.32nm for OCT, CTA, DDA and UTD respectively. The TGA of the modified clays show a gradual weight loss at varying degree of temperature and became stable between 600 and 700oC. These behaviors are indication of good thermal stability of modified clay as it compared favorably with pure and unmodified clay.