A viscometric method for the determination of induction period for polymer thermal oxidation
| Autor: | J. F. Rodrigues, C. C. Bezerra |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
chemistry.chemical_classification
Thermal oxidation Polymers and Plastics Induction period Kinetics Analytical chemistry Viscometer General Chemistry Polymer Condensed Matter Physics Toluene chemistry.chemical_compound chemistry Natural rubber visual_art Polymer chemistry Materials Chemistry visual_art.visual_art_medium Carnauba wax |
| Zdroj: | Polymer Bulletin. 36:347-353 |
| ISSN: | 1436-2449 0170-0839 |
| Popis: | On the basis of viscometry technique a novel method was developed to determine the induction period for polymer thermal oxidation (τi). Natural rubber films from Manihot glaziovii degradated at 90°C were used as a model. Mv values were calculated by using the equation: [η] = 1.9 × 10−Mv0.745 in toluene at 30°C. A random chain scission process was applied. A plot of 1nN (N is the number of broken bonds, C=C in case of rubber) versus time of heating shows two lines. The first indicates no degradation (1nN=1nNo, to t≤τi) while the second represents the real kinetics of the process (1nN=1nNo-k (t-τi), to t≥τi). The intersection of these lines is the induction period of thermal oxidation. The effect of a protective agent, carnauba wax, was tested. The resolution of the method is comparable to that of chemiluminescence and is superior to that of IR and DSC. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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