Nanocellulose as a Sustainable Alternative to Improve the Performance of Resins for Additive Manufacturing

In a plea to become more sustainable, the construction industry is increasing the demand for research on partially replacing synthetic resins with renewable and more environmentally friendly resources, such as biomass. Having good properties, epoxy resins have been an excellent candidate in composites for construction applications. However, it is a relatively brittle material, with a poor resistance to crack initiation and growth. Reinforcing epoxy composites with renewable and mechanically strong materials like nanocellulose is progressively considered recently. In this research, different percentage of bleached and unbleached cellulose nanofibers (BCNF/LCNF) were used to reinforce and partially replace epoxy resin in composites containing Epon 828 and Jeffamine d-400 catalyst. The chemical interaction between cellulose nanofiber and epoxy resin was investigated by quartz crystal microbalance with dissipation monitoring (QCM-D). Mechanical and thermal performances of the reinforced resin were studied using tensile test and thermal gravimetric analysis (TGA) method, and the elemental analysis, Fourier transform infrared spectroscopy (FTIR), was employed on the cured reinforced resin in order to understand the composition of the mixtures after nanocellulose addition. The results proved that the nanocellulose addition changes the chemical composition of epoxy resin, and based on the QCM-D data, BCNF showed favorable chemical interactions with the resin. The mechanical tests indicated the promising results and they proved that the BCNF can be used as a biodegradable and sustainable additive and partially replacement for epoxy resin in composite materials. BCNF reinforced epoxy showed better tensile performance compare to LCNF one. For both LCNF and BCNF dispersed epoxy, the maximum enhancement in tensile properties occurred with 1 wt.% nanomaterial added. It should be noted that the moisture stability of the wood composites was not significantly affected by the nanocellulose content, however, the thermal stability decreased slightly.