High performance sustainable barrier materials are sought to replace synthetic polymers whose composition or manufacturing process presents ecological challenges. Polysaccharides are natural polymers already produced in large volumes for many industries including papermaking and food production. Cellulose, starch, chitin and their chemical derivatives including carboxymethyl cellulose and chitosan are among the highest volume least expensive biopolymers produced. These polymers, however, are highly hydrophilic and do not provide barrier performance against aqueous solutions. Exceptional barrier behavior using these polymers has been recently achieved by combining them in polyelectrolyte complexation. Specifically, cationic chitosan and anionic carboxymethyl cellulose have been combined under high shear forming nanostructured particles that electrostatically coalesce during dehydration forming a dense insoluble material. Current studies demonstrate that this material is resistant to the penetration of aqueous solutions (pH 3-9, 1M NaCl), oils and solvents. Remarkably, edible films less than 10 microns in thickness (approximately 4 mg/in<sup>2</sup>) formed on paperboard surfaces can meet the TAPPI T559 standard for grease resistance. This work demonstrates that electrostatic complexation can be used to produce sustainable polysaccharide-based materials with unprecedented performance useful for replacing synthetics or higher cost alternatives in many high volume applications including paper, packaging, food, textiles, construction and biomedical.

Sustainable barrier materials based on polysaccharides in polyelectrolyte complexation

254th National Meeting (2017)

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