Cellulose Nanocrystals from Lignocellulosic Raw Materials, for Oxygen Barrier Coatings on Food Packaging Films

Cellulose nanocrystals (CNCs) are unique, renewable top-down nano particles from which coatings withimproved gas barrier properties and new functionalities can be prepared. In this paper, the potential forobtaining such high performing nanocrystals from low-cost lignocellulosic by-products or raw materialsis proved by a comparison study on CNCs obtained both from cotton linters and kraft pulp, by means ofthe ammonium persulfate (APS) process. Morphological and chemical characterization of the nanocrystalsobtained, as well as the main functional properties of the poly(ethylene terephthalate) coated films, showe dquite similar characteristics and performances of CNCs obtained from pure cellulose raw material (cottonlinters) and the nanoparticles produced from a potential discard of paper making proc esses (kraft pulp).In particular, the gas barrier properties of the coating produced with CNCs obtained from kraft pulp werevery promising, providing oxygen and carbon dioxide permeability values hundreds of times lower thanthose of equal thickness in comparison with common barrier synthetic polymers, over a broad range oftemperatures. The results obtained are relevant not only for the outstanding performances achieved, but alsobecause they evoke a possible positive example of industrial symbiosis in the packaging field, mergingtogether the requirements and needs of the paper and plastic industries and addressing the way towards abetter management of waste and materials. Copyright © 2017 John Wiley & Sons, Ltd.