title: Double emulsions for the compatibilization of hydrophilic nanocellulose with non-polar polymers and validation in the synthesis of composite fibers.
abstract: A route for the compatibilization of aqueous dispersions of cellulose nanofibrils (CNFs) with a non-polar polymer matrix is proposed to overcome a major challenge in CNF-based material synthesis. Non-ionic surfactants were used in CNF aqueous dispersions equilibrated with an organic phase (for demonstration, a polystyrene solution, PS, was used). Stable water-in-oil-in-water (W/O/W) double emulsions were produced as a result of the compromise between composition and formulation variables. Most remarkably, the proposed route for CNF integration with hydrophobic polymers removed the need for drying or solvent-exchange of the CNF aqueous dispersion prior to processing. The rheological behavior of the double emulsions showed strong shear thinning behavior and facilitated CNF-PS co-mixing in solid nanofibers upon electrospinning. The morphology and thermal properties of the resultant nanofibers revealed that CNFs were efficiently integrated in the hydrophobic matrix which was consistent with the high interfacial area of the precursor double emulsion. In addition, the morphology and quality of the composite nanofibers can be controlled by the conductivity (ionic strength) of the CNF dispersion. Overall, double emulsion systems are proposed as a novel, efficient and scalable platform for CNF co-processing with non-polar systems and they open up the possibility for the redispersion of CNFs after removal of the organic phase.
authors.affiliation: Department of Forest Biomaterials, North Carolina State University, Campus Box 8005, Raleigh, NC 27695, USA. carlos.carrillo@invista.com.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Carrillo
authors.forename: Tiina
authors.initials: T
authors.lastname: Nypelö
authors.forename: Orlando J
authors.initials: OJ
authors.lastname: Rojas
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D009994:Osmolar Concentration; D011108:Polymers / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry; D012212:Rheology; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D004655:Emulsions; D011108:Polymers; D011137:Polystyrenes; D013501:Surface-Active Agents; D002482:Cellulose