Tunable mechanical properties of glass fiber/epoxy composites by incorporating bioinspired montmorillonite–carbon nanotube/epoxy interface layer around the fiber

The mutual exclusiveness between strength and toughness restricts the engineering application of glass fiber/epoxy composites requiring both high strength and suitable toughness. Inspired by natural nacre, a hetero-structural montmorillonite−multiwalled carbon nanotube (Mt−MWCNT) hybrid was coated on the curved surface of glass fibers to construct a nacre-like interface layer, consisting of Mt as “brick”, MWCNTs as “anchor” and initial epoxy resin as “mortar”. MWCNTs were employed for guaranteeing the effective separation of Mt nanosheets and strong interfacial interactions among the Mt, matrix and fiber. The enhanced dispersion degree of Mt−MWCNT hybrids and strongly bonded interface layer were established, and synergistic effects of Mt and MWCNTs on the strength and toughness of composites were also demonstrated. Compared with pure glass fiber/epoxy composite, interlaminar shear strength and work of break of resulting composites were improved by approximately 28% and 189%, respectively; meanwhile, such composite exhibits higher storage modulus in the glassy region and superior thermal stability. This work demonstrates a practical and effective strategy for fabricating high-performance yet low-cost fiber-reinforced composites through the nature-inspired interface.