Comparative study about preparation of poly(lactide)/Organophilic montmorillonites nanocomposites through melt blending or ring opening polymerization methods

The present article is focused onto the study of nanostructure, thermal and mechanical properties of nanocomposites composed of poly(lactide) (PLA), and a constant amount of montmorillonite (MMT) clays (3 wt %). Properly modified organoclays with easily available commercial compounds were prepared in order to allow the homogeneous dispersion of the hydrophilic clays in the polar polymer matrix; in particular, 2-hydroxyethyl-trimethylammonium (choline), polyethyleneoxide(15)-(hydrogenated tallow)-ammonium, and oligochitosan salts were used as surfactants as their structure can match the requirements of a biocompatible material. These organically modified MMTs (OMMTs) were used for preparing composites by melt blending or by in situ ring opening polymerization (using the clay surfactant as polymerization initiator) followed by melt dispersion into a PLA matrix. Structural, morphological, and thermo-mechanical properties of the products are compared in order to assess advantages and disadvantages of the two different preparation routes.