학술논문
Investigation of the degree of homogeneity and hydrogen bonding in PEG/PVP blends prepared in supercritical CO2 : Comparison with ethanol-cast blends and physical mixtures
Document Type
Article
Source
Subject
*SUPERCRITICAL fluids
*HYDROGEN bonding
*POLYETHYLENE glycol
*POVIDONE
*CARBON dioxide
*ETHANOL
*DIFFUSION
*FOURIER transform infrared spectroscopy
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Language
ISSN
0896-8446
Abstract
Abstract: The degree of homogeneity and H-bond interaction in blends of low-molecular-mass poly(ethylene glycols) (PEG, M w =400, 600, 1000) and poly(vinylpyrrolidone) (PVP, M w =9×103) prepared in supercritical CO2, 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 CO2 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 CO2. This reduced interaction was attributed to a combination of: (1) shielding of PEG–PVP H-bond interactions when CO2 is dissolved in the blend; (2) rapidly reduced PEG and PVP chain mobility upon CO2 venting, delaying rearrangement for optimum PEG–PVP H-bond interaction. [Copyright &y& Elsevier]