Synthesis of Poly(ε-caprolactone)/Clay Nanocomposites Using Polyhedral Oligomeric Silsesquioxane Surfactants as Organic Modifier and Initiator

Poly(epsilon-caprolactone)/clay nanocomposites were synthesized by in situ ring-opening polymerization of epsilon-caprolactone in the presence of montmorillonite modified by hydroxyl functionalized, quaternized polyhedral oligomeric silsesquioxane (POSS) surfactants. The octa(3-chloropropyl) polyhedral oligomeric silsesquioxane was prepared by hydrolytic condensation of 3-chloropropyltrimethoxysilane, which was subsequently quaternized with 2-dimethylaminoethanol. Montmorillonite was modified with the quaternized surfactants by cation exchange reaction. Bulk polymerization of e-caprolactone was conducted at 110 degrees C using stannous octoate as an initiator/catalyst. Nanocomposites were analyzed by X-ray diffraction, transmission electron microscopy, thermo gravimetric analysis, and differential scanning calorimetry. Hydroxyl functionalized POSS was employed as a surface modifier for clay which gives stable clay separation for its 3-D structure and also facilitates the miscibility of polymer with clay in the nanocomposites due to the star architecture. An improvement in the thermal stability of PCL was observed even at 1 wt % of clay loading. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 936-943, 2011