Experimental investigation on the mechanical properties of multi-walled carbon nanotubes modified glass fiber-reinforced polymer composites

Glass fiber-reinforced polymer (GFRP) composites exhibit restricted mechanical performance, notably in terms of interlaminar shear strength and fracture toughness, as a consequence of the propensity for fiber/matrix fracturing and delamination when subjected to exterior loading. This study elucidates the enhancement of GFRP composites' mechanical characteristics through the integration of multi-walled carbon nanotubes (MWCNTs). A solution dip coating method was used to deposit 0.3 wt% MWCNTs on the glass fiber fabrics to manufacture the MWCNT-modified GFRP composites. A comprehensive experimental investigation was undertaken to evaluate the impact of MWCNTs on the mechanical attributes of GFRP composites across varying thicknesses and layups. Flexural strength, interlaminar shear strength and fracture toughness were investigated through three-point bending, short beam shear and end notch flexural (ENF) tests, respectively. To further decipher the microstructural enhancement mechanisms of MWCNTs in GFRP composites, fractured surfaces post-ENF testing underwent examination using a field-emission scanning electron microscope. The results revealed that MWCNT-modified GFRP composites with a 4-mm thickness and unidirectional orientation displayed optimal mechanical properties, and the MWCNT-modified GFRP composites with a certain layering angle surpassed the mechanical performance of their unmodified, thinnest unidirectional GFRP counterparts. This research thereby presents engineers with a novel design strategy to address the challenges posed by intricate application scenarios, enhancing the versatility and resilience of GFRP composites in advanced applications.