Dipolar correlation and activation energies for the subglass relaxations of chains with asymmetric side groups
✍ Scribed by Ricardo Díaz-Calleja; Evaristo Riande
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 619 KB
- Volume
- 196
- Category
- Article
- ISSN
- 1022-1352
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✦ Synopsis
Abstract
The effect of the location of the halogen atom on the distribution of activation energies associated with the subglass relaxation of poly(o‐chlorophenyl acrylate) (POCPA) and poly(m‐chlorophenyl acrylate) (PMCPA) is studied. Poly(__p‐__chlorophenyl acrylate) (PPCPA) was also investigated, though not in depth due to its low dielectric activity. The high temperature and frequency dependence found for the activation energy on the high temperature side of the subglass relaxations may not correspond only to simple mechanisms associated with the ß‐process but also to more complex mechanisms associated with the glass‐rubber relaxation. Dielectric activity arising from motions about OC^ar^ bonds is responsible for the high dielectric strength exhibited by these polymers. Theoretical calculations based on the rotational isomeric state model are in fair agreement with the experimental relaxation strengths.