Growing Carbon Nanotubes In Situ Surrounding Carbon Fiber Surface via Chemical Vapor Deposition to Reinforce Flexural Strength of Carbon Fiber Composites

Abstract

This study employed novel joint treatments to strengthen the carbon fiber reinforced polymer (CFRP) composites. Vertically aligned carbon nanotubes (VACNTs) were prepared in situ on the catalyst-treated CF surface via the chemical vapor deposition (CVD) method, intertwining into three-dimensional fiber-nets and fully surrounding CF to form an integrated structure. The resin pre-coating (RPC) technique was further used to guide diluted epoxy resin (without hardener) to flow into nanoscale and submicron spaces to eliminate void defects at the root of VACNTs. Three-point bending testing results showed the “growing CNTs and RPC”-treated CFRP composites yielded the best flexural strength, a 27.1% improvement over the specimens without treatment, while the failure modes indicated that the original delamination failure was changed into “flexural failure” with through-the-thickness crack propagation. In brief, growing VACNTs and RPC on the CF surface enabled toughening of the epoxy adhesive layer, reducing potential void defects and constructing the integrated quasi-Z-directional fiber bridging at the CF/epoxy interface for stronger CFRP composites. Therefore, the joint treatments of growing VACNTs in situ via the CVD method and RPC technique are very effective and have great potential in manufacturing high-strength CFRP composites for aerospace applications.

The Influence of Residual Stresses on the Curve Shape—Describing Interface Behavior in “Polymer–Fiber” Systems

“…The ability to use the high strength of thin fibrous reinforcing fillers under various types of external influences appears to be due to the adhesive strength at which external loads are transferred to the fibers [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ].…”

Electrophoretic Deposition of Multi-Walled Carbon Nanotube Coatings on CoCrMo Alloy for Biomedical Applications

“…Moreover, CNTs can be obtained in the form of vertically arranged carbon nanotubes forming three-dimensional meshes. This method of obtaining CNTs is used to produce high-strength composites for aviation applications [19]. CNTs produced on the surfaces of materials increase their strength, in particular their resistance to cracking under dynamic loads [20].…”

“…However, the folding method is not the same, which is why CNTs differ in length, diameter, and twist angle. CNTs are classified into single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) [15][16][17][18][19][20][21][22][23][24]. SWNTs are flexible, while MWCNTs are stiff, rigid, and rod-like structures.…”