Study On Preparation Of Polarity SSBR Containing Polyethylene Oxide Block And Its Properties

With the improvement of people's environmental awareness,green tire technology with low-pollution,low energy consumption and low-cost has become the focus of research.Rubber reinforced by silica?SiO₂?,with the balanced performance among the rolling-resistance,wet-skid and abrasion,is the ideal materials for green tire.However,silica,due to its aggregation,is difficult to disperse uniformly in the rubber matrix and it will degrade the comprehensive performance of rubber products.The interaction between silica and rubber matrix will be enhanced by introducing polar segment into the nonpolar rubber chain.The polarization modification of solution-polymerized styrene-butadiene rubber?SSBR?is significant to the development for preparation of high performance tires in the future.Firstly,the polarity solution-polymerized styrene-butadiene rubber containing PEO segment?SSBR-PEO?was synthesized by one pot method of living anionic polymerization,n-BuLi as initiator,cyclohexane as solvent,divinyl benzene?DVB?as coupling agent,i-Bu₃Al as cocatalyst and ethylene oxide?EO?as polar monomer.The microstructure,molecular weight and molecular weight distribution of SSBR-PEO copolymers were characterized by FT-IR,¹H-NMR and GPC.The results showed that the polar PEO segment was successfully introduced into the molecular chain of SSBR,and the content of bounded styrene,1,2-structure and PEO block of SSBR-PEO copolymers could be precisely controlled.Based on the data of DSC and the Contact Angle,the nonpolar SSBR would obtain polarity without sacrificing its fundamental performance.The controllable design of the polarity level of SSBR can be achieved by changing the content of PEO block.Secondly,the SSBR/SiO₂ and SSBR-PEO/SiO₂ composite materials were prepared by wet intense mixing method,and the performance of SSBR-PEO/SiO₂ composites with different content of PEO was studied by FT-IR,DSC and SEM.The results showed that there was chemical bonding between the hydroxyl of silica and the PEO block in the SSBR-PEO.With the increase of the content of PEO,silica was dispersed more evenly in the SSBR matrixand its aggregation was effectively inhibited.The Mooney viscosity and the bound rubber content of SSBR-PEO/SiO₂ composite materials increased with increasing the content of PEO from 0%to 20%.By RPA analysis,the Payne effect of SSBR-PEO/SiO₂ composite modified with lower content of PEO was better.Finally,the performance of SSBR-PEO/SiO₂ composites modified with lower content of PEO and silane coupling agent Si69 was studied respectively.The results of TGA,RPA and the bound rubber content analysis showed that the polarization modification of SSBR with low content of PEO and silane coupling agent Si69 modification both contributed to the dispersion of silica in the SSBR matrix.However,compared with Si69 modification,polarization modification technology with low content of PEO is more practical due to flexible adjustment of the polarity and low cost.