Reinforcement contribution of cellulose nanocrystals (CNCs) to tensile properties and fracture behavior of triaxial E-glass fabric/epoxy composites

Triaxial E-glass fabric/CNCs/epoxy composites were fabricated using the vacuum-assisted resin infusion pro-cedure. CNCs/epoxy mixtures were prepared through dispersing various amounts of CNCs within two different mixing mediums, i.e., mixture of epoxy/curing agent (technique EC) and curing agent (technique C). The effects of mixing medium (curing agent vs resin system) and CNC concentration (0.125, 0.25 and 0.5 wt%) on tensile modulus, tensile strength and fracture toughness of the composite samples were evaluated as a novel theoretical attempt. Fracture behaviors of composite samples containing a circular hole were investigated based on energy method developed by Griffith & Irwin in fracture mechanics. Incorporation of 0.25 wt% CNCs within epoxy matrix via technique C yielded an increase of 21.1 % in fracture toughness. Enhancements in critical crack length (16.06 %) and critical energy release rate (88 %) of CNCs-modified composites through technique C propose additional energy absorption during fracture.

Automated summary

Triaxial E-glass fabric/CNCs/epoxy composites were fabricated using the vacuum-assisted resin infusion procedure. The effects of mixing medium and CNC concentration on the mechanical properties of the composites were evaluated. Incorporation of CNCs enhanced the fracture toughness and energy absorption during fracture of the composites.