Differential thermal analysis (DTA) was the first thermal analysis technique used to qualitatively characterize natural clays
and respective curves has been used since more than 60 years as their ‘fingerprint’. With the development of microprocessed
equipments in the last decades, derivative thermogravimetric (DTG) curves also may be used for this purpose in some cases,
which also may allow a quantitative characterization of clay components. TG and DTG curves are more indicated than DTA or
DSC curves to identify and to better analyze the several decomposition steps of natural or synthetic organoclays. These questions
are discussed in applications developed to characterize Brazilian kaolinitic clays, bentonites and organophilic clays.
Authors:Jo Dweck, Emerson Paes Barreto, Sergio Meth, and Pedro Mauricio Büchler
organic adsorptive properties, differently exchanged organophilicclays were obtained (through a sodium clay intermediate—VCNa) from a Verde Claro policationic bentonite (VC) from Bravo, Paraiba State, Brazil, by reaction with hexadecyltrimethylammonium
Authors:Emerson Paes Barreto, Mariana Santos Lemos, Isabelle Bulhoes Aranha, Pedro Mauricio Büchler, and Jo Dweck
]. Sodium bentonite are hydrophilic [ 6 ] and do not adsorb organic pollutants. Therefore, they need to be transformed into organophilicclays for that purpose. This transformation may be done through cation exchange of the metal original cations by organic
Authors:Ewa Olewnik, Krzysztof Garman, Grzegorz Piechota, and Wojciech Czerwiński
figure below (Fig 1 ) depicts the montmorillonite organophilization process. Organophilicclay was introduced, using the extrusion method, into polyethylene (PE) matrix in different mass relations (1.5, 3, and 5 %).
Authors:L. C. Morais, J. Dweck, F. R. Valenzuela-Diaz, and P. M. Büchler
The treatment of the effluents of dairy product industries containing lactose is done by a biological process, which reduces considerably the original amount of that sugar. Although the final residual content of lactose is small after treatment, it may cause the eutrophication and/or the superfertilization of the water, which provokes vegetation growth on the water surface, hindering the navigability and increasing the consumption of the dissolved oxygen necessary to the life of the fishes of the river or sea where the treated effluent is poured. In dairy industry, after proper initial processing steps of waste treatment, lactose, as it is water soluble, may still be present in the outgoing effluents. A complementary step by using organophilic clay adsorption, as a further treatment of these effluents, may enhance antipollution procedures, decreasing its final content in the effluents. The present paper deals with the characterization, by thermal analysis of different lactose products, which may be present in the different processing steps as it dissolves in water and then it is recrystallized from it, as well as after being adsorbed by organophilic clay from those effluents, which are very diluted lactose aqueous solutions.
Authors:M. A. García del Cid, M. G. Prolongo, C. Salom, C. Arribas, M. Sánchez-Cabezudo, and R. M. Masegosa
thermosets have good mechanical and thermal properties, epoxy nanocomposites may enhance the properties even at low nanoparticle contents [ 5 ]. To obtain epoxy–clay nanocomposites, the organophilicclay is swollen in the epoxy monomer, after that the curing
Authors:Simone Pereira da Silva Ribeiro, Luciana Rocha de Moura Estevão, Csaba Novák, and Regina Sandra Veiga Nascimento
polymer matrix used was a poly (ethylene-co-butyl acrylate, EBA-30) supplied by Elf-Atochem. The sodium and organophilicclays studied were supplied by Southern Clay, under the trade names “Cloisite Na” (d-spacing of 11.7 Å), “Cloisite 30B” (d-spacing of