Preparation and Characterization of Exfoliated Ldpe/organolaponite Nanocomposites

Polymer-layered silicate nanocomposites have generated great interest due to their improved thermal, mechanical and gas barrier properties compared to conventional composites or neat polymers. Since the surface of most polymers is usually hydrophobic and layered silicate nanoparticles are completely hydrophilic, interactions between them are not favourable. Thus, the first step in the direction of a nanocomposite synthesis is to convert the hydrophilic clay surface to organophilic, by an ionexchange reaction between the metal cations in the interlayer region and alkylammonium surfactants, or to use a compatibilizer in order to achieve miscibility between the two phases [1]. Low density polyethylene (LDPE) is a widely used packaging material, and the preparation of nanocomposites is expected to improve its barrier properties. However the achievement of nanocomposite structure is much more difficult than in HDPE because of the branched macromolecules (in LDPE) which hinder the penetration into the clay galleries [2]. The objective of this study is to synthesize LDPE based nanocomposites with organo-modified synthetic laponite. The structure of the resulting composites was investigated by X-ray diffraction. Also the thermal and mechanical properties of the obtained materials were evaluated and correlated to their structure.