Nano clay reinforced PCL/starch blends obtained by high energy ball milling

Sodium montmorillonite was incorporated into a poly(epsilon-caprolactone)-starch blend by means of a ball mill. The structural organization and physical (mechanical, thermal and barrier) properties were analyzed and correlated with the milling conditions. Scanning electron microscopy and X-ray characterization show that the milling process can improve the compatibilization between the PCL and the starch phases, while promotes the dispersion of clay minerals at nanometric level. The milling time strongly influences the mechanical and barrier properties. In particular, the best results in terms of elastic modulus and permeability coefficient were achieved with a complete delamination of the pristine clay structure. In summary, the milling process not only has demonstrated to be a promising compatibilization method for immiscible PCL-starch blends, but it can be also used to improve the dispersion of nanoparticles into the polymer blends. (C) 2008 Elsevier Ltd. All rights reserved.