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Effects of rubber curing ingredients and PhenolicResin on mechanical, thermal, and morphological characteristics of rubber/phenolic-resin blends

Derakhshandeh, B ; Sharif University of Technology | 2008

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  1. Type of Document: Article
  2. DOI: 10.1002/app.28034
  3. Publisher: 2008
  4. Abstract:
  5. This article examines the physical and mechanical characteristics of mixtures of two different synthetic rubbers, namely styrene-butadiene rubber (SBR) and nitril-butadiene rubber (NBR), with novolac type phenolicresin (PH). According to Taguchi experimental design method, it is shown that the addition of PH increases the crosslinking density of rubber phase probably due to its curative effects. Thermal analysis of the blends indicates that, contrary to NBR/PH blend, thermal stability of SBR/PH blend is dependent on sulfur content due to predominant polysulfidic crosslinks formed in SBR. Slight shift in glass-transition temperature (Tg) of pure SBR and NBR vulcanizates by the addition of PH suggests that both SBR/PH and NBR/PH are incompatible blends with a partially soluble PH in the rubber phase. Two-phase morphology of the mixtures is also evidenced by scanning electron microscopy. Correlation of the rubber/PH modulus versus PH concentration by Halpin-Tsai model shows a deviation from the model. Presence of PH in the rubber phase is thought to vary the mechanical properties of the rubber phase by changing both the crosslinking density and rigidity of the molecular network of the rubber, leading to misuse of modulus of pure rubber in Halpin-Tsai equation. © 2008 Wiley Periodicals, Inc
  6. Keywords:
  7. ABS resins ; Blending ; Butadiene ; Concentration (process) ; Density (specific gravity) ; Glass transition ; Mechanical properties ; Microscopic examination ; pH ; Phenolic resins ; Phenols ; Resins ; Rigidity ; Rubber ; Styrene ; Sulfur ; Synthetic rubber ; Thermoanalysis ; Thermodynamic stability ; Butadiene rubbers ; Cross links ; Crosslinking densities ; Curative effects ; Mechanical characteristics ; Molecular networks ; Morphological characteristics ; Novolac ; pH increases ; Phase morphologies ; Phenolic-resin ; Resin blends ; Scanning electrons ; Sulfur contents ; Taguchi experimental designs ; Thermal analysis ; Thermal stabilities ; Transition temperatures ; Vulcanizates ; pH effects ; Cross linking ; Glass transition temperature ; Mechanical property ; Morphology ; Physical property ; Resin ; Scanning electron microscopy ; Synthetic rubber ; Thermal property
  8. Source: Journal of Applied Polymer Science ; Volume 108, Issue 6 , 2008 , Pages 3808-3821 ; 00218995 (ISSN)
  9. URL: https://onlinelibrary.wiley.com/doi/abs/10.1002/app.28034