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5716243 
Journal Article 
INTERPRETATION OF THE TAN delta PEAK HEIGHT FOR PARTICLE-FILLED RUBBER AND POLYMER NANOCOMPOSITES WITH RELEVANCE TO TIRE TREAD PERFORMANCE BALANCE 
Warasitthinon, N; Robertson, CG 
2018 
1 
Rubber Chemistry and Technology
ISSN: 0035-9475
EISSN: 1943-4804 
AMER CHEMICAL SOC INC 
AKRON 
91 
3 
577-594 
WOS:000450910500005 
The aim of this research is to clarify the meaning of the peak height for the viscoelastic loss tangent (tan delta) in the glass transition region of particle-filled rubber, polymer nanocomposites, and polymer systems in general. Filler, oil, and curative loadings were systematically varied in a model styrene-butadiene rubber formulation with carbon black as the reinforcing filler. The dynamic mechanical responses of these compounds enabled a detailed study of the glass-to-rubber softening transition, which is known to play an important role with respect to the balance of traction, handling, and rolling resistance characteristics of tire treads. From the temperature-dependent viscoelastic results that were acquired at fixed frequency and small dynamic strain, it was demonstrated that a higher peak value for tan delta was correlated with a lower dynamic modulus in the rubbery state. Adjusting filler volume fraction was found to be an effective way of changing the rubbery modulus and hence the tan delta peak height. It was furthermore verified that such a correlation is a universal material-independent viscoelastic effect by mathematically producing a similar trend by varying the rubbery modulus parameter in the Havriliak-Negami viscoelastic model. This investigation also showed why glass transition temperature should be determined from the position of the loss modulus peak and not the tan delta peak. Cure behavior, tensile stress-strain properties, and extent of filler networking (Payne effect) for these rubber compounds will additionally be discussed.