Chemical Modification Of Ssbr And Its Application In Tread Rubber

With the implementation of the tire label method,the performance requirements for tires are getting higher and higher.Solution polymerized styrene butadiene rubber（SSBR）with excellent performance is applied to tread rubber formula,however,the polarity of non-polar SSBR and the filler silica commonly used in green tires is very different,and silica is easy to agglomerate,which affects the performance of composite materials.The purpose of expanding the application of SSBR in this article first explores the application of two new brands SSBR in tread rubber,in order to provide guidance for their applications in high-performance tires.In order to enhance the compatibility of rubber matrix and silica,SSBR was epoxidized to obtain epoxidized solution polymerized styrene butadiene rubber（ESSBR）with different epoxy degrees.The structural characterization of the ESSBR and the role between ESSBR and silica was explored and ESSBR was used as a compatibilizer for silica with SSBR,NR,NR/SSBR,respectively,the rubber-filler interaction force is increased by the reaction of epoxy group and silica surface silicon hydroxyl group,and the effects of ESSBR on the content of bound rubber content,filler dispersion,vulcanization characteristics,crosslinking density,physical and mechanical properties and dynamic mechanical properties of composite materials were explored.The results show that the dispersion of silica in FX 5021 compound is better,and the vulcanization rate of FX 5021 compound is slower.FX 5021 vulcanized rubber has higher tensile strength and modulus,while FX 3211 vulcanized rubber has higher tear strength,rebounce and abrasion resistance.FX 5021 vulcanized rubber has higher wet slip resistance and rolling resistance,depending on the glass transition temperature,the FX 3211 is more suitable for all-season universal tires and the FX 5021 is more suitable for high-performance tires or racing tires.The structure of ESSBR was characterized by ¹H NMR and infrared spectroscopy,its oxidation position was proved to be 1,4-double bond.The higher the epoxy degree of ESSBR,the higher the glass transition temperature（Tg）;The reaction between silica and ESSBR was studied by the model compound,and the model compound was hot pressed,the torque change during hot pressing and the comparison of infrared and tensile properties before and after hot pressing proved that ESSBR reacted with silica to form a crosslink-like structure.Using ESSBR with different epoxy degrees and different dosages as a compatibilizer for silica and SSBR,ESSBR can improve the dispersion of silica,increase the bound rubber content and crosslinking density,increase the hardness of the vulcanized rubber,reduce the compression heat,improve the wear resistance,improve the wet slip resistance,reduce the rolling resistance,but excessive epoxy will have an adverse effect on tensile strength and rebounce.When ESSBR with different epoxy degrees and NR are used together,it can also improve silica dispersion,increase the bound rubber content,increase the crosslinking density,and improve the dynamic mechanical properties,unlike SSBR/ESSBR/SiO₂system,the increase of epoxy degree has little effect on tensile strength.Finally,ESSBR with different epoxy degrees was added to the NR/SSBR/SiO₂system,and compared with the composite materials added to Si69,it was found that ESSBR with high epoxy degree was better than ESSBR with low epoxy degree in improving silica dispersion,enhancing wear resistance,and improving dynamic mechanical properties,and the effect of Si69 could be exceeded when the amount of ESSBR-30 reached a certain amount,but ESSBR-5 could improve the dispersion of fillers while retaining the rebounce of composite materials.