Study On Fatigue Properties Of NR、SBR And Its Blend Rubber

The variation of micro-and meso-scopic structure and properties during tension fatigue process in silica filled NR and SBR system was investigated by means of dynamic mechanic analysis,broad dielectric relaxation spectrum,solid NMR,TEM and so on.The effect of cross-linking density,coupling agent content,and the dynamic deformation amplitude on fatigue performance was detected.The evolution model for unfilled and silica filled systems were confirmed.The results showed that the fatigue life was mainly determined by the cross-linking density,and almost not affected by the molecular chains for unfilled system.The multiple-sulfur cross-linking bonds were shortened during tension fatigue.It decided the segment mobility after fatigue for unfilled system.Nevertheless,the fatigue life was mainly determined by filler-polymer for silica filled system.The silica aggregates formed “agglomerates” after fatigue,and the agglomerates size was much larger as increase of dynamic deformation amplitude.It was caused by multiple-sulfur cross-linking bond shortening and orientation-like structure of the molecular chains around the surface of silica.The multiple-sulfur cross-linking bond shortening behavior was mainly affected by cross-linking density and the cross-linking bond type.However,the orientation-like structure was mainly affected by coupling agent and dynamic deformation amplitude.The CB aggregates were easy to move to the phase,where its content was lower,from the phase,where its content was higher for CB filled NR/SBR blends.However,the silica aggregates were easy to move to the phase,where its content was higher,form the phase,where its content was lower for silica filled NR/SBR blends.It led to the nonlinear relationship between the NR/SBR ratio and fatigue performance during the fatigue processing for filler system.