Mechanical characterization of cellulose nanofiber and bio-based epoxy composite

Cellulose nanofibers are one class of natural fibers that have resulted in structures with remarkable mechanical properties. In this study, the cellulose nanofibers are used as reinforcements in the forms of layered films in a bio-derived resin. Assessment of swelling behavior is performed together with an assessment of the tension and fracture behavior. Crack resistance behavior is compared to glass fiber systems and strategies for improving the fracture toughness of “nanopaper” based composites are discussed. Swelling tests indicate the need for constitutive and analysis approaches that account for the swelling response of the developed composites. Increased porosity is observed with higher reinforcement volumes leading to lower than expected mechanical properties. Techniques with higher consolidation pressures are required to improve consolidation processes.

► SEM, TEM and microsturcture image analysis of nanocellulose/bioresin composites.
► Low fracture toughness at interfaces in nanocellulose/bio-based resin composites.
► Swelling in nanofiber shows significant volumetric changes in water and epoxy resin.
► Measured porosity increased with increasing nanofiber content.
► Higher fiber content causes modest modulus gains due to increased porosity.