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| Titel: |
Autooxidation of Oriented Polyolefins |
| Auteur: |
Shibryaeva, L. S. Kiryushkin, S. G. Zaikov, G. E. |
| Verschenen in: |
International journal of polymeric materials |
| Paginering: | Jaargang 16 (1992) nr. 1-4 pagina's 71-93 |
| Jaar: |
1992-02-01 |
| Inhoud: |
The effect of the chemical structure of the polymer on its reactivity in the oriented state is studied, and causes of the effect of orientation drawing of polyolefins on the oxidation kinetics are identified. The orientation drawing of the polymer is shown to be dependent on the nature of the latter which can either delay or accelerate the oxidation process. The effect of a delayed rate of oxidation for the samples of one drawing degree is determined by the nature of the side substitute in the monomeric link of the polymer. The effect of the orientation drawing of the polymer on the change of parameters of oxidation (k2k6-0.5 [RH]), a decrease of the coefficients of solubility and diffusion of oxygen as well as the change in the polymer structure depending on its nature are considered. Analysis of structural changes in the polymers due to orientation has shown that drawing of the polymer can result in localization of oxidation in defected zones of amorphous areas isolated from each other by transition chains in extremely straightened conformation. In this case, the oxidation kinetics of oriented polyolefins can be described with the use of postulates of the “zone” model developed by Yu. A. Shlyapnikov. Evaluation of the kinetic parameters of oxidation (k2eff, k6eff, θ) with the use of this model is made. It is shown that the effect of the nature of the polymer is due to a change in activity of the C-H bonds participating in the oxidation process, peculiar features of changes in the structure and physical properties of the polymer in the process of orientation drawing, in terms of the “zone” model, to the rate of the expansion of the oxidation center, that is, the nature of the polymer determines the parameters k2eff, k6eff, θ in the oriented sample. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 4 van 32 gevonden artikelen
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