Quantitative Study on Solubility Parameters and Related Thermodynamic Parameters of PVA with Different Alcoholysis Degrees
In recent years, inverse gas chromatography (IGC) and molecular dynamics simulation methods have been used to characterize the solubility parameters and surface parameters of polymers, which can provide quantitative reference for the further study of the surface and interface compatibility of polyme...
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| Autores principales: | , , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/28ade6924fb04a8794dc30726ab05fef |
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| Sumario: | In recent years, inverse gas chromatography (IGC) and molecular dynamics simulation methods have been used to characterize the solubility parameters and surface parameters of polymers, which can provide quantitative reference for the further study of the surface and interface compatibility of polymer components in the future. In this paper, the solubility parameters and surface parameters of two kinds of common alcoholysis, PVA<sub>88</sub> and PVA<sub>99</sub>, are studied by using the IGC method. The accuracy of the solubility parameters obtained by the IGC experiment is verified by molecular dynamics simulation. On the basis of this, the influence of repeated units of polyvinyl alcohol (PVA) on solubility parameters is studied, so as to determine the appropriate chain length of the PVA for simulation verification calculation. The results show that the solubility parameters are not much different when the PVA chain length is 30 and above; the numerical trends of the solubility parameters of PVA<sub>88</sub> and PVA<sub>99</sub> at room temperature are the same as the results of molecular dynamics simulation; the dispersive surface energy <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi mathvariant="sans-serif">γ</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">d</mi></msubsup></mrow></semantics></math></inline-formula> and the specific surface energy <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi mathvariant="sans-serif">γ</mi><mi mathvariant="normal">s</mi><mrow><mi>sp</mi></mrow></msubsup></mrow></semantics></math></inline-formula> are scattered with the temperature distribution and have a small dependence on temperature. On the whole, the surface energy of PVA<sub>99</sub> with a higher alcoholysis degree is higher than that of PVA<sub>88</sub> with a lower alcoholysis degree. The surface specific adsorption free energy (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>Δ</mo><msup><mi mathvariant="normal">G</mi><mrow><mi>sp</mi></mrow></msup></mrow></semantics></math></inline-formula>) indicates that both PVA<sub>88</sub> and PVA<sub>99</sub> are amphoteric meta-acid materials, and the acidity of PVA<sub>99</sub> is stronger. |
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