Preparation and characterization of blends made of poly(L-lactic acid) and β-cyclodextrin: Improvement of the blend properties by using a masterbatch

beta-Cyclodextrin (beta-CD), an enzymatically modified starch with a hydrophilic exterior and a hydrophobic cavity, can form inclusion complexes with a variety of hydrophobic molecules. In this study, beta-CDs were mixed with poly(L-lactic acid) (PLA) and then extruded, pelletized, and cast into sheets to create biodegradable and bio-based materials with the capacity to carry hydrophobic molecules to enable new applications for polymers in the food and pharmaceutical packaging area. The effects of different beta-CD contents (0, 15, or 30%), and that of using a masterbatch (MB) (pellets containing 30% beta-CD content) on the morphology and the physical properties of the PLA/beta-CD blends were investigated. Thermal stability, tensile strength, modulus of elasticity, elongation at break, and oxygen and water-barrier capacity of the PLA decreased with higher beta-CD contents and revealed that beta-CDs and PLA are incompatible. Similarly, the crystalline content and color change increased with higher beta-CD contents. The addition of beta-CDs in the form of a masterbatch notably reduced these effects and increased the compatibility of the PLA and the beta-CDs. (C) 2011 Elsevier Ltd. All rights reserved.