Influences of tensile drawing on structures, mechanical, and electrical properties of wet-spun multi-walled carbon nanotube composite fiber

A composite fiber based on multi-walled carbon nanotube (MWCNT) and poly(vinyl alcohol) (PVA) is prepared by wet-spinning and then stretched uniaxially with various draw ratios. Structural features and the mechanical and electrical performances of the MWCNT/PVA composite fiber are investigated as a function of draw ratio. It is identified from polarized Raman spectroscopy that the composite fiber exhibits an enhanced alignment of MWCNTs along the fiber axis with increasing the draw ratio. Accordingly, initial moduli and tensile strengths of the drawn composite fibers are much higher than those of undrawn composite fiber because of the efficient stress-transfer between MWCNTs. In addition, electrical conductivity of the composite fiber is significantly increased with the increase of the draw ratio, which is explained by the fact that the alignment of MWCNTs in drawn composite fibers enhances the interaction between MWCNTs, eventually leading to the generation of more efficient paths for electrical conduction.