Super-strong CNT composite yarn with tight CNT packing via a compress-stretch process

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Science

Background:

• Developing large-diameter carbon nanotube yarns (CNTY) with superior mechanical properties is crucial for advanced applications but remains challenging.
• Existing methods struggle to achieve the desired size and performance for CNTY.
• Carbon nanotubes (CNTs) offer exceptional intrinsic properties, but their effective assembly into macroscopic yarns is key.

Purpose of the Study:

• To develop a novel method for producing highly densified, large-diameter carbon nanotube composite yarns.
• To investigate the influence of a compressing and stretching technique on the dispersion and properties of CNT/PVA composite yarns.
• To evaluate the mechanical, electrical, and physical characteristics of the produced CNT/PVA-P CY.

Main Methods:

• A compressing and stretching method was employed to create CNT/PVA-P CY.
• Polyvinyl alcohol (PVA) was used as a matrix to disperse within CNT bundles.
• Characterization included measurement of diameter, tensile strength, Young's modulus, density, and electrical conductivity.

Main Results:

• An ultra-large diameter CNT/PVA-P CY (∼140 μm) was successfully produced.
• The yarn demonstrated excellent mechanical properties: tensile strength up to 1475 MPa and Young's modulus up to 24.98 GPa.
• High electrical conductivity (792 S cm⁻¹) and desirable flexibility and anti-abrasive properties were achieved.

Conclusions:

• The compressing and stretching method effectively disperses PVA within CNT bundles, yielding robust composite yarns.
• The produced CNT/PVA-P CY exhibits a unique combination of large size, high strength, and conductivity.
• These findings offer new insights for CNTY fabrication and suggest potential replacement of traditional carbon fibers in various applications.