Rheological Characterization of Starch-based Biodegradable Polymer Blends

Starch-based polymer blends are often investigated materials that attract great attention due to their disposition to combine advantageous properties of their components and ability to create materials with controlled biodegradation rate. In this contribution the rheological characterization of plasticized starch blended with biodegradable polyester poly (c-caprolactone) was carried out. For preparation of thermoplastic starch-based blends three different types of starches (wheat, corn and tapioca) were used. Two-step preparation process consisting of solution casting and melt mixing was performed and their rheological and thermomechanical behavior was analyzed. Moreover, morphological study on prepared blends was performed. Since the final properties of polymer blends depend directly on blend composition, the adjusting of the material components concentrations and using distinct processing procedures led to materials with various final morphologies and rheological properties as well. Different rheological behavior in the case of TPS (tapioca)/PCL blends compared to wheat or corn starch blended with PCL was observed. Whereas the latter two blends, as well as their neat starch components, exhibited gel-like behavior over the entire measured temperature range, tapioca starch/PCL blends behave as liquids at processing temperatures. The rheology findings about tapioca starch and its blends with polycaprolactone could be advantageously used for preparation of new starch-based polymer materials with controlled biodegradation and enhanced processability.