On the thermal degradation of poly(vinyl chloride). IV. Initiation sites of dehydrochlorination
| Autor: | Erling M. Sörvik, Kent B. Abbås |
|---|---|
| Rok vydání: | 1976 |
| Předmět: |
chemistry.chemical_classification
Degree of unsaturation Allylic rearrangement Materials science Polymers and Plastics General Chemistry Polymer Branching (polymer chemistry) Polyene Vinyl chloride Surfaces Coatings and Films chemistry.chemical_compound chemistry Tacticity Polymer chemistry Materials Chemistry Thermal stability |
| Zdroj: | Journal of Applied Polymer Science. 20:2395-2406 |
| ISSN: | 1097-4628 0021-8995 |
| DOI: | 10.1002/app.1976.070200909 |
| Popis: | A set of poly(vinyl chloride) samples were investigated with respect to their thermal stability. The dehydrochlorination rates were measured in nitrogen at 190°C by use of a very accurate, conductometric method. For all polymers studied, a significant molecular weight increase was observed after 0.4% conversion. With only one exception, samples exhibiting higher degradation rates showed higher absorptions (350–450 nm) after 0.4% dehydrochlorination. In addition, the relative amount of short polyene sequences was found to be higher for polymers with higher degrees of branching. The dehydrochlorination reaction was predominantly initiated at sites of internal unsaturation (allylic chlorines), but an initiation at tertiary chlorines and unstable end-groups could not be completely omitted. Head-to-head units, extraneous impurities, and syndiotactic sequences were found to be of minor importance in this respect. |
| Databáze: | OpenAIRE |
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