Spin-label studies of blends of immiscible polymers: 6. Phase morphology in blends of poly(methyl methacrylate) and poly(2-ethyl hexyl methacrylate)
| Autor: | G. Gordon Cameron, David Stewart |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
chemistry.chemical_classification
Materials science Polymers and Plastics Organic Chemistry Polymer Poly(methyl methacrylate) Miscibility law.invention chemistry.chemical_compound chemistry Chemical engineering law Phase (matter) visual_art Polymer chemistry Materials Chemistry visual_art.visual_art_medium Methyl methacrylate Spin label Thermal analysis Electron paramagnetic resonance |
| Zdroj: | Polymer. 37:5329-5334 |
| ISSN: | 0032-3861 |
| DOI: | 10.1016/s0032-3861(96)00379-5 |
| Popis: | The correlation times, τR, for rotation in the slow-motion regime of nitroxide free radicals sited at chain-end positions on poly(methyl methacrylate) (PMMA) in the pure, unblended state and in a 1:1 ( w w ) freeze-dried blend with unlabelled poly(2-ethyl hexyl methacrylate) (PEHMA) were determined by computer simulation of the slow-motion component of the composite electron spin resonance (e.s.r.) spectrum. Comparison of τR values indicates that the rubbery PEHMA apparently plasticizes the rotation of nitroxide-labelled PMMA chain ends which are expected to be located in the pure glassy PMMA phase. Although the spin-label studies seem to suggest that PMMA and PEHMA are partially miscible, dynamic mechanical thermal analysis (d.m.t.a.) and phase-contrast microscopy prove that PMMA-PEHMA blends comprise two separate phases which are essentially immiscible. The conclusions from the e.s.r., d.m.t.a. and phase-contrast microscopy experiments can be reconciled in terms of a wide-diffuse interphase between the bulk PMMA and PEHMA phases. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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