Development of sizing-free multi-functional carbon fibre nanocomposites

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms AbstractHigh quality multi-walled carbon nanotubes (CNTs) grown at high density using a low temperature growth method are used as an alternative material to polymer sizing and is utilised in a series of epoxy composites reinforced with carbon fibres to provide improved physical and electrical properties. We report improvements for sizing-sensitive mechanical and physical properties, such as the interfacial adhesion, shear properties and handling of the fibres, whilst retaining resin-infusion capability. Following fibre volume fraction normalisation, the carbon nanotube-modified carbon fibre composite offers improvements of 146 % increase in Young's modulus; 20% increase in ultimate shear stress; 74 % increase in shear chord modulus and an 83 % improvement in the initial fracture toughness. The addition of CNTs imparts electrical functionalisation to the composite, enhancements in the surface direction are 400%, demonstrating a suitable route to sizing-free composites with enhanced mechanical and electrical functionality.

Multi-Functional Carbon Fibre Composites using Carbon Nanotubes as an Alternative to Polymer Sizing

“…This is a remarkable result considering the difference in V f between each sample (fibre volume fraction of (48.5 ± 0.5)% for the CFRP and (20.0 ± 2.0)% for the F-CFRP used in this test18.…”

“…The weight change of the fabric during the growth process is displayed in Fig. 1h showing an initial reduction of weight of 1.7 wt.%, which occurs as a the result of the removal of the polymer sizing via a thermal annealing process518. The weight increase from this value is the result of weight gain by the CNT growth.…”

“…1f) and of the cross-section of the composite (Fig. 1i) (see Supplementary Note 2 for method) on the composite revealed ~40% of the fibres are covered by the CNTs (where growth is present)18 with CNT lengths in the range of 10–300 μm, and growth densities (where growth had occurred) of ~2 × 10 10 tubes cm −2 . As evident by Fig.…”

“…The examination of the physical and mechanical properties of the CNTs as a replacement for the polymer sizing are presented elsewhere18. To summarise, following fibre volume fraction normalisation, enhancements of: 146% in the Young’s modulus; 20% in the ultimate shear stress; 74% in shear chord modulus and 83% in the initial fracture toughness were observed18.…”

Continuous carbon nanotube synthesis on charged carbon fibers

“…The most prevalent method to limit carbon fiber damage during the synthesis of CNT on carbon fiber substrates is the application of a barrier coating to the fiber surfaces, which limits catalyst contact with the fiber substrate. Common barrier coatings include silicon/silica [30][31][32][33][34][35][36], alumina [37][38][39] or pyrolytic carbon. [40][41][42] However, recently, we reported that the application of a modest potential difference minimized carbon fiber damage and improved the CNT coverage without the requirement for a barrier coating.…”