Effectiveness of short and straight carbon nanotubes on dispersion state and static/dynamic mechanical properties of woven glass fibre-reinforced polymer laminates

Abstract

This study reports about the dispersibility of short, straight and pristine multi-walled carbon nanotubes (pCNTs) in epoxy and their effectiveness on the mechanical properties of three-phased GF/epoxy/pCNT laminates. These nanotubes were produced by arc discharge method and had an average aspect ratio (l/d) of 100. Glass fibre-reinforced polymer samples with four different weight fractions of these nanotubes (0.5, 1.0, 1.5 and 2.0 wt.% of the total matrix system) were fabricated and tested for their thermo-mechanical and mechanical properties. These carbon nanotubes with small aspect ratio contributed well to the strengthening mechanism due to their homogeneous dispersion. Fractography revealed that these nanotubes formed aligned arrays that minimized entanglements between the individual tubes, thus leading to lesser agglomerates up to 1.5 wt.% of carbon nanotube loading. However, the samples modified with 2.0 wt.% of nanotubes had lesser individual tubes and more of their aggregates. Unmodified glass fibre-reinforced polymer samples had a glass transition temperature (Tg) of 139.2℃, whereas addition of 1.5 wt.% of multi-walled carbon nanotubes increased the same to 160℃. Similarly, these specimens witnessed about 21% and 34% enhancement in tensile and flexure strength over the control samples, respectively. However, these trends dropped at 2.0 wt.% carbon nanotube loading owing to nanotubes aggregation but were higher than those of the neat epoxy composite. Samples containing carbon nanotubes witnessed higher fatigue life which proves that multi-walled carbon nanotubes with smaller aspect ratio are capable of obstructing fatigue crack growth.

Comparative study of the influence of graphene nanoplatelets filler on the mechanical and tribological behavior of glass fabric‐reinforced epoxy composites

“…They showed that incorporation of 0.5 wt% nano‐silica exhibited the maximum enhancement in tensile strength as well as higher elongation at break (higher ductility) compared to other specimens. Singh and Gaurav [ 27 ] investigated the tensile properties of GFRE polymer composite filled with MWCNTs. Their study revealed that tensile strength improved, and Young's modulus decreased as the MWCNT contents were increased from 0.5 to 1.5 wt%.…”

“…[17][18][19] As per the literature review, the optimum weight percentage of nano fillers is 0.2 to 2 wt%, which ensures improved tribo-performance while retaining or even improving other mechanical properties. [20][21][22][23][24][25][26] Singh and Gaurav [27] studied the mechanical and thermomechanical properties of GFRE composites filled with multi-walled carbon nanotubes (MWCNTs) (0.5, 1.0, 1.5, 2 wt%). They concluded that the addition of MWCNTs upto 1.5 wt% facilitates enhancement in tensile strength and glass transition temperature.…”

Observations of fatigue damage development in woven glass fiber-reinforced polymer composite using transmission light photography technique

“…Glass fibers are stiffer than the adjacent matrix, and upon loading the apparent modulus gap causes considerable strain difference instigating high shear forces in the fiber-matrix interface. 33 Magnitude of the shear force developed on the fiber/matrix interface largely depends upon the stress magnitude; where high shear forces are generated in the fiber/matrix interface when the specimens are loaded at high stresses causing fractures mostly dominated by fiber pullouts. On the contrary, samples loaded at low stresses undergo fiber breakage rather than pullouts, mostly due to low shear stresses acting on the fiber/matrix interfaces.…”

“…These cracks require a large number of cycles to propagate and the samples experience high fatigue life. 33 Larger cracks that eventually propagate in fewer cycles create a large plastic zone ahead of the advancing cracks. While these advancing cracks propagate in the matrix, they leave behind intact fibers, which bridge the cracks.…”

The effects of graphene nanoplatelets on the tribological performance of glass fiber-reinforced epoxy composites

“…[22][23][24][25] As per the literature review, the optimum weight % of nanofillers is in a range of 0.2 to 2 wt.%, which ensures improved tribo-performance while retaining or even improving other mechanical properties. 9 Singh and Gaurav 26 studied the mechanical and thermomechanical properties of GFRE composites filled with multiwall carbon nanotubes (MWCNTs) (0.5, 1.0, 1.5, 2 wt.%). They concluded that the addition of MWCNTs up to 1.5 wt.% facilitates enhancement in tensile strength and glass transition temperature.…”