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首页> 外文期刊>Journal of Applied Polymer Science >Effect of Interactions Between Poly(vinyl alcohol) and Urea on the Water Solubility of Poly(vinyl alcohol)
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Effect of Interactions Between Poly(vinyl alcohol) and Urea on the Water Solubility of Poly(vinyl alcohol)

机译：聚乙烯醇与尿素相互作用对聚乙烯醇水溶性的影响

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摘要

Poly(vinyl alcohol) (PVA) is an important water-soluble polymer. Its many applications (e.g., textile sizing, dispersants, and adhesives) greatly depend on its water solubility and particularly on its dissolution rate in water. In this study, urea, combined with methanol, was adopted to improve the water solubility of PVA. The structures, properties, and dissolving mechanism of the modified PVA were studied with Fourier transform infrared spectroscopy, NMR, laser light scattering, differential scanning calorimetry, and wide-angle X-ray diffraction. The results showed that through specific chemical reactions between PVA and Urea in methanol, isocyanate and methyl carbamate groups were generated on the lateral chains of PVA. These large side groups could effectively expand PVA macromolecular chains and hence increase their intermolecular distance, weaken the intramolecular and intermolecular hydrogen bonds of PVA, change the aggregation structure of PVA, and decrease its lattice energy and crystallinity. In addition, the isocyanate groups on the PVA macromolecular chains strongly interacted with water. All these effects benefited the water solubility of PVA. Therefore, the dissolution rate of the modified PVA increased by 50%, versus that of the neat PVA, and the quality of the modified PVA aqueous solution was improved quite a bit.
机译：聚乙烯醇（PVA）是重要的水溶性聚合物。它的许多应用（例如，纺织品上浆剂，分散剂和粘合剂）在很大程度上取决于其水溶性，尤其取决于其在水中的溶解速度。在这项研究中，尿素结合甲醇被用来提高PVA的水溶性。利用傅里叶变换红外光谱，核磁共振，激光散射，差示扫描量热法和广角X射线衍射技术研究了改性PVA的结构，性质和溶解机理。结果表明，通过PVA与尿素在甲醇中的特定化学反应，在PVA的侧链上生成了异氰酸酯和氨基甲酸甲酯基团。这些大的侧基可以有效地扩展PVA大分子链，从而增加它们的分子间距离，削弱PVA的分子内和分子间氢键，改变PVA的聚集结构，并降低其晶格能和结晶度。另外，PVA大分子链上的异氰酸酯基团与水强烈相互作用。所有这些作用有益于PVA的水溶性。因此，与纯的PVA相比，改性的PVA的溶解度提高了50％，并且改性的PVA水溶液的质量得到了相当大的改善。

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