Starch-based nanocomposites by reactive extrusion processing

Nanocomposites with unique material properties have been prepared from synthetic plastics and nanosilicates (nanoclay) until now, but not from biopolymers such as starch. The primary challenge in making biopolymeric nanocomposites is to achieve strong adhesion between nanoclay and polymer matrix. For the first time nanocomposites with superior properties have been successfully made from starch-polycaprolactone (PCL) blends in the presence of montmorillonite (MMT) nanoclay. Reactive extrusion results showed that addition of a modified nanoclay at 3 % wt level increased elongation almost fourfold over that of pristine starch-PCL blends. X-ray diffractions results showed dispersion of clay in the polymer matrix. The nanocomposites have better solvent-resistance properties because of resistance to diffusion offered by clay platelets in the polymer matrix. (C) 2004 Society of Chemical Industry.