ORIGINAL PAPER Mechanical and fire retardant properties of EVA/clay/ ATH nanocomposites: effect of functionalization of organoclay nanofillers Miguel A ´ ngel Ca ´rdenas • Fe ´lix Carlos Basurto • David Garcı ´a-Lo ´pez • Juan Carlos Merino • Jose ´ Marı ´a Pastor Received: 21 August 2012 / Revised: 10 December 2012 / Accepted: 26 January 2013 / Published online: 6 February 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract A new modification process for the preparation of organoclay has been devised. Functional organoclay nanofillers (FONs) based on the mixing of bentonite and other inorganic fillers such as fumed silica, aluminium trihydroxide (ATH) and sepiolite were prepared and employed to obtain composites of ethylene–vinyl acetate and ATH. These composites were characterised by means of X-ray dif- fraction, thermogravimetric analysis, mechanical and fire retardant properties. The results confirmed that the modification process for the preparation of FONs is able to influence the intercalated structure of the clay, and hence the mechanical prop- erties and behaviour as flame retardant materials. Keywords Organoclay Á Nanocomposites Á EVA Á ATH Á Mechanical properties Á Fire retardant properties Introduction Ethylene–vinyl acetate (EVA) copolymers are extensively used in the cable industry as excellent insulating materials with good mechanical properties. To reduce the large amount of smoke produced during combustion, metal hydroxides, such as aluminium trihydroxide (ATH), are added to the polymer. However, the inclusion of these additives causes the mechanical properties of these materials to decrease significantly. Thus, the combination of bentonite nanoclay with other inorganic M. A ´ . Ca ´rdenas Á F. C. Basurto (&) Á J. C. Merino Á J. M. Pastor Departmento de Fı ´sica de la Materia Condensada, Escuela de Ingenierı ´as Industriales, Universidad de Valladolid, Paseo del Cauce 59, 47011 Valladolid, Spain e-mail: felbas@cidaut.es D. Garcı ´a-Lo ´pez Á J. C. Merino Á J. M. Pastor Centro de Investigacio ´n y Desarrollo en Automocio ´n, CIDAUT, Parque Tecnolo ´gico de Boecillo, 47151 Boecillo, Valladolid, Spain 123 Polym. Bull. (2013) 70:2169–2179 DOI 10.1007/s00289-013-0925-0