Facile fabrication of PVA composite fibers with high fraction of multiwalled carbon nanotubes by gel spinning

Abstract

Poly(vinyl alcohol) (PVA) composite fibers with high fraction of multiwalled carbon nanotubes (MWCNTs) were prepared by gel spinning process. Here, a modified process was introduced to prepare concentrated PVA/MWCNTs/ DMSO spinning dope, and to attain good dispersion of MWCNTs in the fibers. The final composite fibers were studied by thermogravimetric analyzer (TGA), Fourier transform infrared spectrometer (FTIR), Raman spectroscopy, differential scanning calorimetry (DSC), and WAXD analysis. The total content of MWCNTs in PVA composite fibers, from 5 to 30 wt%, was confirmed by TGA analysis. FTIR and Raman measurements demonstrated the existence of strong hydrogen interaction between MWCNTs and PVA matrix. SEM images of composite fibers showed smooth surface, regular cross-section shape and good dispersion of MWCNTs in the fibers. DSC analysis showed that the crystallinity first increased and then decreased with the increase of MWCNTs contents. It can be concluded that low concentration of MWNCTs can act as nucleation sites for crystallization of PVA component, and large amount of MWCNTs may impede the crystallization of PVA component. The WAXD analysis results indicated that the crystal orientation of the PVA component in PVA composite fibers is almost identical at the same drawn ratio. Polarized Raman analysis indicated a small increase in MWCNTs orientation for the composite fibers. The mechanical properties tests showed that the composite fibers exhibit significant improvement in tensile strength and modulus as compared to the neat PVA fibers. The composite fibers also showed sustained growth in electrical conductivity. POLYM. ENG. SCI., 58:37-45, 2018.

Preparation of high molecular weight polyvinyl alcohol by emulsifier-free emulsion polymerization

“…In the FTIR spectra, the characteristic absorption peak at about 3312 cm -1 was caused by the -O-H asymmetric stretching vibration band. In addition, the absorption peaks at about 2943 cm -1 , 1660 cm -1 , 1426 cm -1 and 1088 cm -1 were caused by -C-H stretching vibration, C-C framework stretching vibration, -C-H flexural vibration and C-O stretching vibration, respectively [8]. These indicated that the product prepared in this paper was PVA.…”

The effect of degree of polymerization on the structure and properties of polyvinyl alcohol fibers with high strength and high modulus

“…In addition, the absorption peaks at about 2938, 2906, 1660, 1424, and 1091 cm −1 were caused by CH 2 asymmetric and symmetric stretching vibration, C C framework stretching vibration, CH flexural vibration and C O stretching vibration, respectively. 23,24 In a comparison of the spectra of PVA and PVA fibers, although the characteristic absorption peaks of other groups had little change (within 2 cm −1 ), the OH stretching vibration absorption peaks of PVA moved toward lower wavenumber after PVA fibers were prepared, indicating that the distance between molecular chains of the PVA fibers was decreased and hence, the possibility of forming hydrogen bonds in the PVA fibers was increased. 25 The formation of hydrogen bonds was beneficial in developing high strength and high modulus of PVA fibers.…”

“…where ΔH 0 m 161 J g − 1 ð Þis the melting enthalpy for 100% crystalline PVA. 23,27 The crystallinities of PVAs were increased from 20.6% to 35.6% with an increase in DP. The increase of crystallinity was nearly 75% from the PVA with low DP (1899 and 2099) to high DP (2499, 2699, 3599).…”

Structure, properties, and applications of polyacrylonitrile/carbon nanotube (CNT) fibers at low CNT loading

“…), and additional processing conditions such as thermal annealing or CNT functionalization. [4][5][6][7][8][9][10][11][12][13] High CNT loading of 20 wt% results in higher conductivity of the polymer/ CNT fibers up to 240 S/m. [14] However, high CNT loading also contributes to high raw material cost, as well as the high energy cost of filler dispersion, and results in low fiber mechanical properties.…”