Structure and properties of extruded composites based on bio-polyesters and nano-chitin

Abstract

A renewable feedstock on a worldwide scale is chitin waste material from the seafood industry, exceeding 25 billion tons/year. Recently, it has become possible to produce pure chitin crystals, named “chitin nanofibrils” (CN) for their needle-like shape and nanostructured average size 1. The CN are thus available on an industrial scale in water suspension. Biodegradable polyesters, such as poly(lactic acid) (PLA) are widely investigated for their potential applications in many sectors. The preparation of CN composites can result in improved mechanical and antimicrobial properties. These composites were melt extruded to achieve a good level of dispersion by employing suitable plasticizers to pre-disperse NC. The complete removal of water from the plasticizer/NC pre-composite was essential to avoid chain scission2 in the successive extrusion step. The electron microscopy investigation of materials showed the absence of micrometric agglomerates thanks to the adopted preparation method. The effect of plasticization, crystallinity evolution and reinforcement were kept into account to rationalize the results of tensile and DSC tests. (1) P. Morganti, G. Morganti, A. Morganti, Nanotechnology, Science and Applications, 2011:4 123–129 (2) F. Signori, M. B. Coltelli, S. Bronco, Polymer Degradation and Stability 2009: 94 74–82 Aknowledgements: Authors acknowledge the financial support of EC Seventh Framework Programme, SME-2012-1, grant agreement n° 315233, n-Chitopack project