Cellulose nanocrystals effect to improve mechanical properties of epoxy-based glass fiber-reinforced composites

Abstract

This work investigated the effect of incorporating cellulose nanocrystals (CNCs) into epoxy resin to enhance the mechanical properties of the glass fiber-reinforced polymer (GFRP) nanocomposites, with the goal of identifying the optimal CNC content based on mechanical and thermal performance. CNCs obtained via acid hydrolysis were added in varying weight percentages (0.5, 1, and 1.5 wt%) to the epoxy resin. The formation of molecular bonds between CNCs and epoxy resin was confirmed through Fourier-transform infrared (FTIR) and Raman spectroscopy methods. Results revealed that the addition of 1 wt% CNCs notably enhanced the mechanical properties, including a 24% increase in tensile strength and 25% improvement in elastic modulus compared to the neat epoxy sample. Scanning electron microscopy (SEM) further demonstrated improved adhesion between glass fibers and epoxy at this concentration, attributing enhanced interfacial bonding to the hydrogen interactions between CNCs and glass fibers. The highest CNC content of 1.5 wt% resulted in agglomeration, leading to a moderate reduction in mechanical properties. However, this sample with a 30% improvement still exhibited a higher modulus than the neat epoxy due to restricted chain mobility. The thermal analysis showed an increase of 4.5 °C in glass transition temperature in the 1.5 wt% CNC/epoxy-based GFRP composite sample. The findings suggested that CNCs significantly improved the mechanical and thermal performance of the GFRP/CNCs-epoxy nanocomposites, making them promising for high-performance applications in aerospace, automotive, and construction industries.

Graphical abstract