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RESEARCH PRODUCT
PEO/CHCl3. Crystallinity of the Polymer and Vapor Pressure of the Solvent. Equilibrium and Nonequilibrium Phenomena
Bernhard A. WolfAlbina Kh. Khasanovasubject
chemistry.chemical_classificationPolymers and PlasticsEthylene oxideVapor pressureOrganic Chemistrytechnology industry and agricultureConcentration effectPolymerFlory–Huggins solution theoryAmorphous solidInorganic Chemistrychemistry.chemical_compoundCrystallinitychemistryChemical engineeringMaterials ChemistryOrganic chemistryBinary systemdescription
Vapor pressures were measured for the system CHCl3/PEO 1000 (PEO stands for poly(ethylene oxide) and 1000 for Mw in kg/mol) at 25 °C as a function of the weight fraction w of the polymer by means of a combination of headspace sampling and gas chromatography. The establishment of thermodynamic equilibria was assisted by employing thin polymer films. The degrees of crystallinity α of the pure PEO and of the solid polymer contained in the mixtures were determined via DSC. An analogous degree of polymer insolubility β was calculated from the vapor pressures measured in this composition range. The experiments demonstrate that both quantities and their concentration dependence are markedly affected by the particular mode of film preparation. These nonequilibrium phenomena are discussed in terms of frozen local and temporal equilibria, where differences between α and β are attributed to the occlusion of amorphous material within crystalline domains. Equilibrium information was obtained from two sources, namely f...
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2003-07-23 | Macromolecules |