Effect of tackifiers on mechanical and dynamic properties of carbon‐black‐filled NR vulcanizates

This work focuses on the effect of tackifiers on mechanical and dynamic properties of carbon‐black‐filled vulcanizates. Three types of tackifiers with difference in softening points are selected for study including petroleum resin, phenolic resin, and gum rosin. The effect of tackifiers on the retardation of vulcanization is observed and the changes in mechanical properties due to the reduction in crosslink density are correlated. Good compatibility between natural rubber and all three tackifiers is verified by a single tan‐delta peak detected for each vulcanizate in temperature ramp test. A similar behavior to the Payne effect which usually found in the case of particulate‐filled rubbers is observed for the tackifier‐filled counterparts. The variation of temperature plays a crucial role in the dynamic behavior of tackified vulcanizates since the state of tackifiers determines its function during dynamic straining. As temperature passed through the softening point of a particular tackifier, substantial reduction in elastic response is observed; however, its relative damping to the untackified may still be maintained. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers.