Cellulose Nanofiber Coated Carbon Fiber/Epoxy Composite with Higher Mechanical Strength

A simple synthetic technique can produce cellulose nanofibers (CNF) from plant cellulose microfibers. These fibers are discontinuous, highly graphitic, and can be disseminated in an isotropic or anisotropic mode. They are also very compatible with most polymer processing processes. The dry carbon fiber can be physically adjusted by adding CNF because it is accessible in a free-flowing powder form. In this work, the impact of CNF compositions, shape, and mechanical properties on carbon fiber is investigated. The CNF composite nanofiber networks are used as interleave layers in epoxy/carbon fiber laminate composites to improve interlaminar shear strength (ILSS), flexural strength, and tensile strength. Following a solvent exchange process to disperse CNF in an appropriate solvent for easy coating of the carbon fiber surface, bath sonication is used with different volume fractions of CNF to coat dry carbon fiber (0.6 wt.%, 0.8 wt.%, 1 wt.%). The volume percentage of CNFs and their fracture properties in enhanced carbon fiber reinforced polymer (CFRP) laminates have been widely researched. Following annealing, 8 layers of CNF coated carbon fibers are layered and infused with epoxy resin using the vacuum-assisted resin transfer molding (VARTM) method under high pressure, followed by an oven curing procedure. When dry carbon fiber is treated with CNF, the laminate exhibits increased mechanical strength in some circumstances. Laminates are made by coating the dry carbon fiber surface with CNF, which improves the mechanical properties of the random composite nanofiber networks significantly over a tidy sample. The use of CNF composite nanofiber networks as an interleaved layer in an epoxy/carbon laminate boosts ILSS delamination resistance by 27.2 % and 12.4 % in 0.8 wt% and 1 wt% CNF, respectively, but no significant difference is detected in 0.6 wt% CNF, when compared to the neat control sample. When measuring the mechanical strength of these laminates, it was discovered that the neat sample reached a maximum load of 978N before plummeting. The addition of 0.8 wt% CNF to the carbon fiber increases the laminate's maximum load-bearing capability to 1338N. Furthermore, the flexural strength and modulus of 0.8 wt. % CNF coated carbon fiber laminate improves significantly. This finding implies that CNF can help an epoxy/carbon laminate resist delamination under stress and deformation. This is due to fracture path modification and load energy absorption by higher modulus CNFs reinforced nanofibers interleaving in the laminate, giving the networks a greater shear modulus.