Synthesis Of End-Group Functionalized Styrene Butadiene Rubber With Siloxane As End-capping Agent

The rapid development of modern transportation and transportation has put forward higher requirements for rubber as a tire material.Solution polymerized styrene butadiene rubber(SSBR)has become an important tread rubber material due to its balanced physical and chemical properties.However,in actual production and life,the safety performance of a single SSBR can no longer meet the needs of use,and its functional modification has become a research focus.Therefore,siloxane with a structure similar to that of the post-processed filler silica is selected for modification,in order to improve the wet skid resistance and mechanical properties.In this paper,an anionic polymerization method is used,with butadiene(Bd)and styrene(St)as monomers,n-butyllithium(n-Bu Li)as initiator,and 2,2-bis(tetrahydrofuran)propane(DTHFP)as the structure Modifiers,vinyl trimethoxy silane(TIVS)and allyl trimethoxy silane(TIOS)are used as end-capping agents to prepare SSBR functionalized with alkoxysilane.Use end-capping agent TIVS or TIOS to carry out small-scale polymerization of homopolymer polystyrene(PS)and polybutadiene(PB)end group functional modification,by gel permeation chromatography(GPC),Fourier transform Infrared spectrometer(FTIR)and proton nuclear magnetic resonance spectrometer(~1H-NMR)are used to characterize and analyze the capped structure.The results show that both capping agents can cap PS and PB,but side reactions are prone to occur.For capping with TIOS,it is necessary to add 1,1-stilbene(DPE)cap before capping to prevent side reactions;and for capping with TIVS,the effect of DPE capping is poor.Choose a new capping agent ethylene oxide(EO),successfully synthesize the target product.The end-group functionalization of the copolymer solution polymerized styrene-butadiene rubber(SSBR)is subjected to mode polymerization by the above-mentioned end-capping method.The structural characterization analysis shows that the TIVS end-group functionalized styrene-butadiene rubber(SSBR-TIVS)and the TIOS end-group functionalization are successfully synthesized.Styrene butadiene rubber(SSBR-TIOS).Further,the factors that affect the blocking efficiency of SSBR-TIOS are explored,and the results show that as the blocking time,temperature and molecular weight increase,the blocking efficiency first increases and then decreases;as the ratio of the blocking agent to the initiator increases Increase,the end-capping efficiency first decreases and then increases.When the end-capping time is30min,the reaction temperature is 60℃,the molar ratio of the end-capping agent to the initiator is 2,and the molecular weight of SSBR is 60000,the end-capping efficiency is the highest,which is the best end-capping condition.SSBR-TIVS and SSBR-TIOS are polymerized with the best end-capping conditions of SSBR-TIOS as experimental conditions.After processing and vulcanization,the mechanical properties and mechanical properties of vulcanizates of SSBR-TIVS,SSBR-TIOS and blank SSBR are compared and studied.Dynamic mechanical properties.The results show that the mechanical properties and wet skid resistance of SSBR modified by TIVS and TIOS have been improved.Among them,the mechanical properties of SSBR-TIVS are improved more obviously,and the wet skid resistance of SSBR-TIOS is improved more significantly.Since the capping agent EO can undergo self-polymerization,the effect of the amount of EO used on the performance of SSBR is explored.The results show that as the content of EO increases,the wet skid resistance of rubber decreases.