Bentonite is a technical term applied to layered silicates of very thin granulation, mainly composed by minerals of the smectites group. Montmorillonite, a phylossilicate with layers as thick as 1 nm, is the most common structure in the bentonite clay. The polarity of these materials is incompatible with most of the usual polymers and in order to overcome this problem, chemical modifications are often necessary. The purpose of this work is to evaluate the chemical and physical characteristics of different bentonites by comparing their product data sheets, their performance in the water Foster swelling and their response to chemical modifications of their surfaces structures. The samples were characterized by infrared spectroscopy and X-ray diffraction analysis. All bentonite samples showed effective intercalations of the modifying agent on their surface structures. This behavior showed the possibility of usage of these materials in the polymer layered silicates nanocomposites preparations.