Cellulose nanocrystals barrier properties

Fortunati, E., Peltzer, M., Armentano, 1., Torre, L., Jimenez, A., Kenny, J. M. (2012). Effects of modified cellulose nanocrystals on the barrier and migration properties of PLA nano-biocom-posites. (2), 948-956. 

E. Fortunati, M. Peltzer, I. Armentano, A. Jimenez, and J.M. Kenny, Combined effects of cellulose nanocrystals and silver nanoparticles on the barrier and migration properties of PLA nano-biocomposites,/. FoodEng., 118,117-124, 2013. 

Slavutsky et al. (2014) prepared starch/cellulose nanocrystals (CNCs) films and their water barrier properties were studied. The measured film solubility, contact angle, and water sorption isotherm indicated that reinforced starch/CNC films have a lower affinity to water molecules than starch films. Permeability, dififusivity, and solubility coefficients indicated that the permeation process was controlled by the water diffusion and was dependent on the tortuous pathway formed by CNC incorporation. The decrease in surface hydrophilicity and the improvement in water vapor barrier properties with the addition of CNC showed that these nanocomposites present excellent potential as a new biomaterial for application in food packaging and conservation. 

Cellulosic materials, such as cotton and wood pulp, when subjected to acid hydrolysis yield defect-free, rod-like crystalline residues called as cellulose nanocrystals. These are often referred to as microcrystals, whiskers, nanocrystals, nanoparticles, microcrystallites, or nanofibres. Their nanoscale dimension, high surface area, high specific strength, thermal, and mechanical strength along with gas barrier properties increase its merit towards its usage in advanced applications like reinforcement in polymeric matrix to form nanocomposite materials, chemical transformations and so on. 

NPs are used in the preparation of bio-nanocompositesmainly for two reasons, to create tortuous path in order to improve the barrier properties (as filler) and to induce various desired effects (as an additive) such as immobilization of enzymes, antimicrobial activity, biosensing, and so on. Varions types of NPs, including clay and silicates, Cellulose based nano-reinforcements, CNTs, Silica, Starch nanocrystals, chitin and chitosan NPs, and metal oxides, are presently nsed to enhance the biopolymer performance. 

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