Investigation of the degree of homogeneity and hydrogen bonding in PEG/PVP blends prepared in supercritical CO sub(2): Comparison with ethanol-cast blends and physical mixtures

The degree of homogeneity and H-bond interaction in blends of low-molecular-mass poly(ethylene glycols) (PEG, M sub(w) = 400, 600, 1000) and poly(vinylpyrrolidone) (PVP, M sub(w) = 9 x 10 super(3)) prepared in supercritical CO sub(2), ethanol and as physical mixtures were studied by differential sca...

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Bibliographic Details
Published in:The Journal of supercritical fluids 2010-07, Vol.54 (1), p.81-88
Main Authors: Labuschagne, Philip W, John, Maya J, Sadiku, Rotimi E
Format: Article
Language:English
Subjects:
Blends
Carbon dioxide
Differential scanning calorimetry
Dissolution
Ethyl alcohol
Homogeneity
Mechanical analysis
Polymer blends
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Summary:The degree of homogeneity and H-bond interaction in blends of low-molecular-mass poly(ethylene glycols) (PEG, M sub(w) = 400, 600, 1000) and poly(vinylpyrrolidone) (PVP, M sub(w) = 9 x 10 super(3)) prepared in supercritical CO sub(2), ethanol and as physical mixtures were studied by differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy and dynamic mechanical analysis (DMA) techniques. Homogeneity of samples prepared in supercritical CO sub(2) were greater than physically mixed samples, but slightly less than ethanol-cast samples. PEG-PVP H-bond interaction was higher for ethanol-cast blends when compared to blends prepared in supercritical CO sub(2). This reduced interaction was attributed to a combination of: (1) shielding of PEG-PVP H-bond interactions when CO sub(2) is dissolved in the blend; (2) rapidly reduced PEG and PVP chain mobility upon CO sub(2) venting, delaying rearrangement for optimum PEG-PVP H-bond interaction.
ISSN:0896-8446
DOI:10.1016/j.supflu.2010.03.012