Transition phenomena and solid-state structure in glassy polymers
| Autor: | R. D. Andrews |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
chemistry.chemical_classification
Materials science digestive oral and skin physiology Intermolecular force Polyacrylonitrile Thermodynamics Polymer Polyethylene Condensed Matter::Soft Condensed Matter chemistry.chemical_compound symbols.namesake chemistry Melting point symbols Organic chemistry van der Waals force Glass transition Dynamic equilibrium |
| Zdroj: | Journal of Polymer Science Part C: Polymer Symposia. 14:261-265 |
| ISSN: | 1935-3065 0449-2994 |
| DOI: | 10.1002/polc.5070140119 |
| Popis: | The primary and secondary transitions observed in solid polymers have generally been interpreted in terms of the concept of “molecular motions.” A different interpretation is presented here in which these transitions are explained in terms of the thermal breakdown of different types of intermolecular secondary bonding in the solid state. It is assumed that the association-dissociation equilibria involved are governed by normal thermodynamic considerations. The time-temperature (or frequency-temperature) dependence of such transitions can be associated with the “transport rate” (bond formation and breakdown rate) of the dynamic equilibrium involved. The glass transition behavior of polyacrylonitrile and poly(methyl methacrylate) are discussed in terms of the breakdown of dipole-dipole bonding between chains, and it would appear that, the breakdown of hydrogen-bonding and van der Waals bonding are involved in the transitions of nylon and polyethylene, respectively. From this point of view, a glass transition is regarded as having considerable similarity to a melting point, and this consequently provides a theoretical justification for the empirically observed correlation between the principal glass transition and the melting point for a wide variety of polymers. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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