Multiscale characterization and design of cellulose composites based on polymers with movable cross-links

To combine the conflicting properties of impact resistance, stiffness, and toughness, we focused on composite materials reinforced with cellulose nanofibers and polymers with movable cross-links using cyclic macro-monomers and analyzed their mechanical properties through experiments and computational simulations. Based on the experimental foundation, the mechanical properties of cellulose nanofibers modified with citric acid and flexible crosslinked polymer composites using cyclodextrin were investigated. On the other hand, multi-scale finite element analysis simulation based on homogenization theory was employed to systematically clarify the effects of aspect ratio and content ratio of cellulose fibers by considering polymer blending and modification of molecular structure in the base material. For modification of the matrix polymers and the fiber morphologies, the elastic modulus of the cellulose composite was comprehensively organized by the fiber contribution based on strain energy. A design method for cellulose composites based on fiber contribution proportion was also developed. The design method was applied to a new cellulose composite with a different polymer of the matrix, and it was demonstrated that the elastic modulus can be predicted with an error of less than 10 %.