Effect of the orientation and rheological behaviour of biodegradable polymer nanocomposites

The recent increasing interest towards biodegradable polymers has favoured the investigation on these systems, showing also their limits. On the other hand, the success achieved by nanocomposites has fostered the search for new systems where the polymer matrix is biodegradable. The final properties can depend on a number of factors, including the biodegradable polymer used as well as the nanosized filler, their mutual compatibility, the filler dispersion and the processing conditions. In this work, nanocomposites based on a starch-derived matrix and three different lamellar silicates were prepared, and the effects of the elongational flow on the dispersion, the improvement of intercalation/exfoliation and the possible aligning of the nanosilicate particles along the flow direction was investigated. Rheological, morphological and tensile tests showed that the properties were significantly different upon varying the compatibility between the polymer matrix and the nanofiller, as well as the draw ratio and therefore the orientation degree.