Remilling On Filler Dispersion And Rheological Property Of Green Tire Tread

For the production of most rubber products,after being parked,the compounds is usually subjected to back refining before it can be used in subsequent rolling,extrusion,and other production processes.In this paper,the Mooney viscometer,Rubber processing analyzer,Capillary rheometer,Harper torque rheometer,Transmission electron microscope?TEM?and other means were used to study the influence of the back smelting and milling time on the filler dispersion,shear viscosity,inlet pressure drop,extrusion stability and other processing rheological properties of SSBR/CB24 tread rubbers with 70phr silica?67/3 phr silica/graphene composite filler?6 phr grapheme,respectively.The results showed that,with the increase of the milling times?0,5,10,15 and 20?,the Mooney viscosity and the storage modulus G'of the three reinforcing systems gradually decreased,and the Payne effect weakened.The TEM images further observed that the filler dispersion became better.This was related to changes in the content of“bonded rubber”and“bound rubber”caused by the change in the molecular weight of rubber and dispersion of the filler aggregate.Due to partial consumption of scorch time in the milling process,the critical transition temperature of the silica-filled compound at which G'rase during the temperature scan reduced and the processing temperature window narrowed.The compound with three kinds of reinforcing systems exhibited typical“shear thinning”effects under different milling times.At the same shear rate,the more the milling times,the lower the shear viscosity and inlet pressure drop?P_ent.In addition,due to the silylation reaction caused by higher temperature in the system containing silica,the shear viscosity of the compound increases first and then decreases with increasing temperature.As the extrusion rate decreased and the number of milling times increased,the extrusion appearance of the silica and silica/grapheme compound gradually improved.Extrusion appearance was best at 100°C when the mixing speed was 5 r/min and the temperature was 100?.However,the high shear rate could break the filler network,improve the dispersion of the filler,and affect the content of bound rubber.Therefore,when the extrusion rate was 25 r/min,the dispersion of the filler was best.The comprehensive physical and mechanical properties of silica and graphene-filled vulcanizates with 5 time of milling are best.