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Polyvinyl alcohol (PVA) fibers were prepared using PVA with different degree of polymerization (DP) under the same wet spinning process. The effect of the DP of PVA on the structures and properties of PVA and PVA fibers were studied by using nuclear magnetic resonance hydrogen spectroscopy (1H‐NMR), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), differential scanning calorimeter (DSC), thermo gravimetric analysis (TGA), and environmental scanning electron microscope (ESEM). The results showed that DP had little effect on the crystallinity and tacticity of PVA, but had a positive effect on melting temperature, and initial decomposition temperature of PVAs. The hot drawing ratio determined by the spinning process where the PVA fibers could be continuously collected without breaking. The drawing ratio was decreased with an increase of DP, resulting in an increase of the final fiber diameter. The PVA fibers with medium DP and medium size demonstrated high strength and high modulus, but relatively low breaking elongation. It suggested that high DP of PVA was not a guarantee of high strength and high modulus PVA fibers, but rather a primary structure factor. The fiber performance was determined by a comprehensive effect combining a variety of factors including polymer properties and spinning conditions. It provided a guideline for PVA fiber manufacture that the PVAs with different DP require different spinning processes to obtain optimal fiber performance. [ABSTRACT FROM AUTHOR]

To address the challenge of enhancing the mechanical properties of polyvinyl alcohol (PVA) fiber, constrained by the spinning process limitations, this study introduces a PVA/DMSO spinning solution. The solution, with concentrations ranging from 21.0 wt%, utilized PVA polymer (DP of 7499 and S-diad of 53.7 %) as the raw material. This approach facilitated the production of high-strength and high-modulus PVA fibers through a consistent dry-wet spinning method. The viscosity of the spinning solution was determined using a viscometer, while the PVA fibers underwent comprehensive characterization through various testing methodologies. Fourier Transform Infrared (FTIR) spectroscopy analysis revealed an initial increase followed by a decrease in the hydrogen bonding within PVA fibers as the spinning solution concentration increased. Scanning Electron Microscope (SEM) imagery indicated that the surfaces of the PVA fibers were smooth. Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and X-Ray Diffraction (XRD) analyses demonstrated that the melting temperature, thermal decomposition temperature, and crystallinity of the PVA fibers exhibited a similar trend of initial increase and subsequent decrease with rising concentrations of the spinning solution. In addition, mechanical tester indicated that when spinning solution concentration was 22.5 wt% the PVA fibers process best mechanical property, and the breaking strength and elastic modulus reached 15.02 ± 0.5 cN/dtex and 357.12 ± 9.4 cN/dtex, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]