Studies of magnetic resonance phenomena in polymers. I. The effects of free volume and segmental mobility on the motion of nitroxide spin probes and labels in poly(methyl methacrylate)
| Autor: | Jovan Moacanin, Amitava Gupta, Fun-Dow Tsay, Su Don Hong |
|---|---|
| Rok vydání: | 1982 |
| Předmět: |
chemistry.chemical_classification
Nitroxide mediated radical polymerization Materials science General Engineering Polymer Atmospheric temperature range Poly(methyl methacrylate) law.invention Condensed Matter::Soft Condensed Matter chemistry.chemical_compound Nuclear magnetic resonance chemistry Chemical physics law visual_art visual_art.visual_art_medium Methyl methacrylate Electron paramagnetic resonance Spin (physics) Glass transition |
| Zdroj: | Journal of Polymer Science: Polymer Physics Edition. 20:763-772 |
| ISSN: | 1542-9385 0098-1273 |
| DOI: | 10.1002/pol.1982.180200417 |
| Popis: | Thin films of spin-probed and spin-labeled poly(methyl methacrylate) (PMMA) have been examined by electron spin resonance (ESR) at X-band frequency (9.2 GHz) and at various temperatures. Direct spectral evidence is presented to indicate that the composite ESR spectra observed in a certain temperature range originate from two states of distinctly different mobility, one with slow motions corresponding to a glassy state and the other with fast motions corresponding to a liquidlike state. The coexistence of these two states at temperatures considerably below the glass transition temperature can be explained as a result of the effect of free volume in a solid polymeric glass. |
| Databáze: | OpenAIRE |
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