Advances in the cellulose nanofibril (CNF) technologies and applications

Cellulose nanofibrils (CNF) are promising bio-based materials for numerous applications, either as replacement of oil-based materials in existing products, potentially with added functionality, or in generating completely new materials and products. CNFs are already commercially available in significant quantities and commercial products based on them have emerged into markets. However, some challenges still remain with the current production technologies of CNFs. Despite rigorous process development, the production costs often remain high and the resulting material is at low consistency. These obstacles may slow down the spreading of the CNF technologies as well as restrict their applicability for certain water-sensitive applications, such as composites, and prevent long-distance transportation, thus leading to limited availability of the material. Recent advances in the production methods attempt to remove the technology-related barriers. For example, high-consistency enzymatic fibrillation (HefCel) technology developed at VTT offers a cost-efficient way to produce fibrillated cellulose materials at high consistency (20-40%). The process is simple, consisting only of few steps and can utilize existing industrial equipment. The produced fibrillated cellulose material is at high consistency and easy to handle. The higher dry matter content makes off-site production and transportation more feasible compared to traditional CNFs. In addition, progress has been made in the drying technologies of CNFs. CNF-related applications are on a different technology readiness level (TRL). Use of CNF in the board making is already on an established level and its use in liquid packaging as barrier materials has been piloted commercially. The rheological properties of CNF suspensions are well known and their potential as stabilizers in food, cosmetics, paints and oil&gas has been studied to some extent. Promising novel high-value applications with lower TRL include membranes for water and air purification, yarns for textile applications, 3D composites, substrates for printed electronics, optical structures and energy storage. New potential applications arise constantly all over the world. In this presentation, an overview on the advances of CNF technologies and applications will be given, with special emphasis on the applicatios that are of most interest to the audience.