Stress softening in natural rubber vulcanizates. Part IV. Unfilled vulcanizates

✍ Scribed by J. A. C. Harwood; A. R. Payne

• Publisher: John Wiley and Sons
• Year: 1966
• Tongue: English
• Weight: 358 KB
• Volume: 10
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1966.070100811

✦ Synopsis

Stress softening (Mullins effect) is observed in gum natural rubber vulcanizates. The magnitude of this softening is similar to that in carbon black-filled vulcanizates. The amount of stress softening is slightly greater in vulcanizates cured to produce predominantly polysulfide crosslinks than in those containing monosulfide or carbon-carbon crosslinks. The total recovery of stress softening in the vulcanizates containing monosulfide or carbon-carbon crosslinks suggest.s that the phenomenon is attributable to a quasi-irreversible rearrangement of molecular networks due to localized 'nonaffine deformation resulting from short chains reaching the limit of their extensibility. This nonaffine deformation results in a displacement of the network junctions from their initial random state.