Crystallization of Cis-Polyisoprenes in a Capillary Rheometer. I
| Autor: | R. W. Smith, C. E. Wilkes, V. L. Folt |
|---|---|
| Rok vydání: | 1971 |
| Předmět: |
Morphology (linguistics)
Materials science Polymers and Plastics Atmospheric pressure Capillary action Right angle Atmospheric temperature range law.invention Crystallography Natural rubber law visual_art Materials Chemistry Melting point visual_art.visual_art_medium Composite material Crystallization |
| Zdroj: | Rubber Chemistry and Technology. 44:1-11 |
| ISSN: | 1943-4804 0035-9475 |
| DOI: | 10.5254/1.3547355 |
| Popis: | Natural rubber is readily crystallized under the pressure and orientation forces existing in a capillary rheometer. The crystallization of natural rubber is readily effected over the temperature range covering commercial processing and fabricating temperatures. The crystalline rubber is stable at atmospheric pressure and room temperature. The observed crystalline melting point increases with increasing crystallization temperatures. Wide angle x-ray pictures show the crystals to be highly oriented in the direction of flow. Electron micrographs of fracture surfaces of the crystalline rubber show the existence of a very complex morphology. Where the degree of orientation is highest, a fibrillar structure is observed parallel to the direction of flow. The fibrillar structure changes to a shish-kebab structure about midway down the capillary. Apparently, a regrouping occurs with chain folded lamellae forming at right angles to the oriented fibrillar type crystals. A rotation of the chain-folded lamellae may occur as the exit end of the capillary is approached. |
| Databáze: | OpenAIRE |
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