Roles played by novolac resin on rubber compounding, reinforcement and nonlinear rheological behaviors

Reducing the energy consumption of rubber compounding and mediating nonlinear rheological responses of rubber nanocomposites are of great significance in the rubber industry. Herein a low glass transition temperature novolac type phenol-formaldehyde (PF) resin was investigated as a secondary filler that can not only reduce input mechanical compounding power but also be able to reinforce rubber in combination with carbon black (CB). Comparative studies about reinforcement and nonlinear rheological behaviors were performed for compounds with CB, PF or both. It is shown that a partial replacement of PF can act in synergism in the thermal stabilities and take similar reinforcement effect as CB-filled compounds below and above glass transition temperature of PF. Elastic and viscous nonlinearities of dual filler compounds can be effectively retarded and lessened above glass transition temperature of PF because of reduced strain amplification effect. [Display omitted] •Novolac resin (PF) reduces rubber compounding power.•PF reinforces rubber together with carbon black.•PF retards elastic and viscous nonlinearities.