A biobased binder of emulsion type that provides unique and durable wet strength and hydrophobicity to paper and nonwoven.

Using biobased polyelectrolytes to emulsify natural fatty molecules is one possible key technology to create sustainable materials. The emulsions can be used in papermaking instead of synthetic hydrophobizing agents or in nonwoven manufacturing to create strong, hydrophobic textile-like materials. This article investigates a novel emulsification system based on a polyelectrolyte complex between chitosan dissolved in citric acid and carboxymethyl cellulose together with sunflower (Helianthus annuus) oil. Viscose nonwoven treated with the emulsion had a contact angle of over 120°. Tensile tests showed that the produced paper and nonwoven materials achieved high dry and, especially, high wet strength. Infrared spectroscopy illuminated the impact of heat curing the binder, and electron microscopy showed that the oil droplets from the emulsion were spread across the fibre surface. The results from this study enable sustainable nonwovens to be applied in areas where high dry and wet strength and water repellence are required; this includes outdoor applications, including agricultural mulch films, where nonwoven is used frequently and a sustainable approach is urgently needed to reduce the accumulation of plastics in the environment. [Display omitted] • Polyelectrolyte complex based on chitosan and carboxymethyl cellulose can emulsify sunflower oil. • The emulsion can be used as a biobased binder to replace fossil-based binders in nonwoven. • Cellulosic material treated with the binder receive high dry- and wet strength. • Contact angles of more than 120° can be reached with the emulsion-based polyelectrolyte complex binder. [ABSTRACT FROM AUTHOR]