Anionic Synthesis Of Damping Rubber And Study On Microstructure And Properties

High molecular polymer is a typical viscoelastic substance.It has good hysteresis and vibration damping effects.It can absorb mechanical energy and noise generated produced by mechanical operation,and convert part of it into internal energy for consumption.In order to improve the damping performance of polymer materials,the effective damping temperature range of the polymer should be widened as much as possible.The method of increasing the content of the side groups and the rigid groups in the polymer molecular chain can be adopted to increase the friction between each structural unit,thereby achieving the effect of improving the damping performance of the polymer material.In order to further explore the damping properties of styrene-butadiene rubber and styrene-butadiene rubber,the following research is performed in this paper.In order to study the influence of pendant groups on the mechanical properties of styrene-butadiene rubber,first of all,an anionic polymerization method was used in this paper,with hexane/cyclohexane as the solvent,n-butyllithium(BuLi3)as the initiator,and styrene and butadiene(Bd)as Monomer synthesis of polymerized styrene-butadiene rubber.Nuclear magnetic resonance hydrogen spectroscopy(,H-NMR)and gel permeation chromatography(GPC)were used to characterize the SSBR with different St/Bd mass ratio and vinyl content.And by changing the monomer ratio and the amount of structure regulator,SSBR with different St/Bd mass ratio and vinyl content was synthesized to study the relationship between the microstructure of molecular chain and mechanical properties and dynamic mechanical properties.The results show that the effect of St/Bd mass ratio on the mechanical properties and dynamic mechanical properties of SSBR is more obvious.Increasing the St/Bd mass ratio can improve the tensile strength,100%tensile strength and Shore hardness of vulcanizates.While increasing the vinyl content,the tensile strength has decreased.With the increase of St/Bd mass ratio and vinyl content,the dynamic mechanical performance curve of SSBR moves to the high temperature region and the maximum damping factor(tan?max)tends to increase first and then decrease.The glass transition temperature(Tg)Gradually improve.St/Bd mass ratio has a stronger effect on Tg,and can widen the effective damping temperature range of SSBR.In order to further investigate the influence of pendant groups,SSIR was synthesized with cyclohexane as the solvent and n-butyllithium(BuLi3)as the initiator.The polymer structure was characterized by 1H-NMR,Fourier infrared spectroscopy(FTIR)and GPC.The adjustment effect of the new structure regulator ditetrahydrofurfurane(DTHFP)was investigated and compared with the traditional structure regulator tetrahydrofuran(THF)and the highly efficient asymmetric ether ethyltetrahydrofurfuryl ether(ETE)Investigate the effect of St/Ip mass ratio,reaction time and reaction temperature on the microstructure of SSIR.The results show that the mass fraction of polyisoprene 3,4-structure(3,4-Ip)and polyisoprene 1,2-structure(1,2-Ip)in SSIR molecular chain increases with the amount of structure regulator.Among the three structural regulators,DTHFP has the strongest regulating ability.DTHFP has a stronger ability to regulate the polymerization rate of St monomers than IP monomers.When the molar ratio of DTHFP/n-BuLi is 0.50,3,4-Ip structure mass fraction is as high as 0.68.The effect of monomer ratio on the microstruicture is not obvious,but the effect of appropriately reducing the reaction temperature is equivalent to increasing the amount of regulator.Finally,using block copolymerization of ethylene oxide and SSIR,a block polymer with a PEO segment mass fraction of 3.2%and a molecular weight of 1.6×103,and a capping efficiency of 66.6%was synthesized.At the same time,1H-NMR,FTIR,GPC and differential scanning calorimetry(DSC)were used to characterize the modified polymer structure.