Chemical Modifications of Natural Clays: Strategies to Improve the Polymeric Matrix/Clay Compatibility

ROMINA OLLIER; MATÍAS LANFRANCONI; VERA ALVAREZ

Advances in Materials Science Research

Nova Science Publishers

Lugar: Nueva York; Año: 2014; p. 55 - 82

Polymer/clay nanotechnology age started with Toyota?s work about clay particles exfoliation in nylon-6, by the last 80?s and the beginnings of the 90s. The improvements on several properties of the polymeric matrices have been improved by the addition of nanometric scale particles. The most used nanoparticles to reinforce polymeric materials are layered silicates. Their crystalline net consists of bi-dimensional layers where a central octahedral layer of either alumina or magnesia is joined to two external tetrahedrons of silica in such a way that the oxygen ions of the octahedral layer also belong to the tetrahedral layers. In order to obtain the best properties, the key point is the dispersion of the clay particles inside the polymeric matrix but the tendency of the particles to agglomerate is difficult to overcome. In addition, most of the polymers are hydrophilic and original clays are hydrophilic. In order to make them (matrix and clay) more compatible, some chemical treatment will be required. Although there are different ways to optimize the polymer/clay compatibility, the most popular method consists on converting these hydrophilic silicates to organophilic ones by performing chemical treatments of the clay. In this chapter several strategies to modify the inorganic clays and to make them more compatible with polymeric matrices are studied and the effect of each one, together with the relevant parameters, is established.