Influence of functionalized multi-walled carbon nanotubes on mechanical properties of glass fiber reinforced polyester composites

The effect of addition of carboxyl functionalized multi-walled carbon nanotubes (COOH MWCNT) to glass fiber reinforced polymer (GFRP) composites is studied. GFRP composite laminates are fabricated by vacuum resin infusion process (VRIP). Composite laminates are fabricated using neat polyester resin and nano-phased polyester resin (with 0.2, 0.5 wt% MWCNT). Composite laminates with MWCNT were divided into three sections based on the direction of resin flow namely entry, middle and exit. The ability of carbon nanotubes mixed with the resin to reinforce uniformly across the glass fiber mats is investigated by evaluating mechanical properties of specimens at different sections of the laminates. Specimens from entry, middle and exit sections were tested to determine tensile, flexural and inter-laminar properties. Composite laminate with 0.2 wt% MWCNT exhibited good mechanical properties compared to that with 0.5 wt% MWCNT. It could be observed that carbon nanotubes are able to spread across entire glass fiber mats as it resulted in enhancement of mechanical properties in all sections without much variation. It is also noticed that increase in wt% of MWCNT resulted in incomplete wetting of glass fiber mats.