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首页> 外文期刊>Polymers for advanced technologies >Preparation of high-strength, high-modulus PVA fiber by synthesis of syndiotacticity-rich high molecular weight PVA polymers with VAc and VBz via emulsifier-free emulsion polymerization
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Preparation of high-strength, high-modulus PVA fiber by synthesis of syndiotacticity-rich high molecular weight PVA polymers with VAc and VBz via emulsifier-free emulsion polymerization

机译：Preparation of high-strength, high-modulus PVA fiber by synthesis of syndiotacticity-rich high molecular weight PVA polymers with VAc and VBz via emulsifier-free emulsion polymerization

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摘要

Different vinyl acetate (VAc) and vinyl benzoate (VBz) monomer ratios have been cho-sen as monomers to create high polymerization degree (Pn) and high syndiotacticity-diad content (S-diad) poly(vinyl alcohol) (PVA) polymers via emulsifier-free polymerization in order to address the problem of limited mechanical capabilities of PVA fibers prepared with low P(n )and low S-diad polymer. The variations in hydrogen bonding, P-n , S-diad, and viscosity of different PVA polymers were investigated and evaluated using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, and a viscosity tester. Moreover, various PVA fibers with high strength and modulus have been manufactured using a synthetic polymer as the raw material for dry-wet spinning. The effect of P-n and S-diad on the mechanical and thermal character-istics of PVA fibers is evaluated using a variety of characterization techniques, such as the scanning electron microscope, differential scanning calorimetry, thermogravimetric analyzer, X-ray diffraction, and tensile tester. As the ratio of VBz monomer increased, the results suggested that VBz may have a considerable impact on the P-n and S-diad of PVA polymers, the OH vibration absorption peak reduced from 3491 to 3442 cm(-1); the P-n increased from 2112 to 17,704; and the S-diad rose from 51.2% to 60.1%. In addition to the fact that Pn and S-diad significantly increased the fibers' strength and modulus, the crystallinity increased from 41.8% to 51.7%, and the orientation degree rose from 87.5% to 91.7%, as P-n and S-diad increased; the tensile strength and highest elastic modulus increased from 9.71 +/- 0.3 cN/dtex to 12.74 +/- 0.5 cN/dtex (increased of 31.2%) and 264.52 +/- 9.3 cN/dtex to 338.41 +/- 8.6 cN/dtex (increased of 27.9%); the elongation at break decreased from 5.63 +/- 0.3% to 2.92 +/- 0.2%.

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