Eco-Dedigned Cellulose Nanocrystal-PLA biocomposites with Enhanced Barrier Propreties

This work investigates the structure-processing-properties of environmentally friendly multiphase materials. These PLA-based materials are intended for food packaging. However, PLA can only be processed to a limited extent by plastics processing technologies. Its crystallization performance, barrier properties, flexibility and biodegradability under specific conditions are also limited. To overcome these weaknesses, PLA/CNC blends have been prepared separately by melt extrusion. Ternary blends based on PLA/CNC and PEG as agent of CNC coating and plasticizer were also used to improve the ductility of the final material. Thanks to this technology for structuring multilayer materials at micro- and nanometric scales, the initial crystalline morphology is modified into a lamellar/oriented crystalline structure, which is revealed by SAXS/WAXS analyses. This structure is all the more remarkable as the number of nanolayers and their confinement increase, resulting in a 64% reduction in the oxygen transmission rate (OTR). Finally, the study of the structure-processing-property relationships has enabled us to gain a real understanding of how to improve and/or induce the target physical and mechanical properties in complex multiphase systems. Finally, this study proposes innovative and novel strategies for the industrial production of ecological biocomposites based on coextruded multilayers.