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)
✍ Scribed by Tsay, Fun-Dow ;Hong, Su Don ;Moacanin, Jovan ;Gupta, Amitava
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1982
- Tongue
- English
- Weight
- 576 KB
- Volume
- 20
- Category
- Article
- ISSN
- 0098-1273
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
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 GH~z~) 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.