Preparation Method and Performance Study of Nanocellulose/Epoxy Resin Composite Materials Modified by Multiple Approaches

Nanocomposites are pivotal for enhancing epoxy resin performance, but traditional inorganic nanofillers' poor compatibility and nonrecyclability pose environmental concerns. This study utilises recyclable organic cellulose nanocrystals (CNC) to explore their modification impact on epoxy composite properties. Through infrared spectroscopy and X-ray photoelectron spectroscopy (XPS), the degree of modification for CNC and its derivatives—KH560-modified CNC (KH560-CNC) and methyl methacrylate-modified CNC (MMA-CNC)—was assessed. Scanning electron microscope (SEM) performance characterisation of modified CNC/epoxy composites showed that higher CNC modification levels significantly improve the toughness of the composites. Regarding thermal conductivity, modified CNCs affected the epoxy composites differently; KH560-CNC/EP exhibited the best thermal conductivity at low filler concentrations, whereas MMA-CNC/EP showed higher thermal conductivity at high concentrations. Additionally, nanocellulose's varying degrees of modification differently impacted the composites' moisture absorption and dielectric properties. The higher the CNC modification level, the stronger its moisture absorption capability, with minimal effect on dielectric loss. This paper provides experimental evidence for CNC/epoxy composite applications, offering practical guidance for future design and manufacturing of epoxy resin composites.