analysis (TGA) and differential scanning calorimetry (DSC) were
used in this work. Thermogravimetric analysis (TGA) of organoclay
was performed with TGA (STA 6000, Perkin Elmer Co., Ltd., USA)
operated in the temperature range from room temperature to
800 C and a heating rate of 10 C/min under nitrogen atmosphere.
The modifying agent contents in the organoclays were determined
based on the TGA thermograms in the temperature range of
150e500 C, according to equation (1) [19]. That is, the total
exchanged moles of octadecylamine (i.e., modifying agent) per
gram of organoclay (4amm) was estimated.