Mechanical, physical and tribological characterization of nano-cellulose fibers reinforced bio-epoxy composites: An attempt to fabricate and scale the ‘Green’ composite

• The curing kinetics of prepared composites were studied.
• The fiber surface modification as coupling agent of CNFs in bio-based epoxy improved the curing of the resin by reducing the activation energy at very high temperature (130 °C).
• Enhanced tensile strength of the composites reinforced by silyliated CNFs confirmed.
• Composites reinforced by cellulose fibers have lower coefficient of friction and wear.
• The uniform tribo-layer formed during sliding facilitated to reduce ‘direct contact’ and improve tribological properties.

The development of bio-based composites is essential in order to protect the environment while enhancing energy efficiencies. In the present investigation, the plant-derived cellulose nano-fibers (CNFs)/bio-based epoxy composites were manufactured using the Liquid Composite Molding (LCM) process. More specifically, the CNFs with and without chemical modification were utilized in the composites. The curing kinetics of the prepared composites was studied using both the isothermal and dynamic Differential Scanning Calorimetry (DSC) methods. The microstructure as well as the mechanical and tribological properties were investigated on the cured composites in order to understand the structure-property correlations of the composites. The results indicated that the manufactured composites showed improved mechanical and tribological properties when compared to the pure epoxy samples. Furthermore, the chemically modified CNFs reinforced composites outperformed the untreated composites. The surface modification of the fibers improved the curing of the resin by reducing the activation energy, and led to an improvement in the mechanical properties. The CNFs/bio-based epoxy composites form uniform tribo-layer during sliding which minimizes the direct contact between surfaces, thus reducing both the friction and wear of the composites.