Synergistic Modification Of Silica With Terminal Polybutadiene And Silane To Enhance The Structure And Properties Of Natural Rubber

Filler dispersion and the interaction between filler-rubber determine the final properties of the material.Due to the good reinforcing properties of silica,the rubber composites perform excellent dynamic and static mechanical properties,especially in terms of reducing rolling resistance.Due to the high-polarity surface of silica,the interaction between particles to be higher than the interaction between particles and rubber,which easily each other to form agglomerates.In addition,due to the high polarity of the silica surface,it is difficult to evenly disperse in the rubber matrix.Therefore,it is necessary to treat the surface of the filler to reduce the interaction force between silica particles and improve the dispersion of silica in the rubber material.In Chapter 2,tri ethoxy silane-terminated liquid polybutadiene(TTPB)was used to directly modify silica in situ to prepare different amounts of TTPB modified silica/rubber composites.The experimental results show that TTPB can improve the dispersibility of silica and improve the mechanical properties and wear resistance of the rubber compound.When the amount of TTPB is 5Phr,the rubber compound has lower rolling resistance and significantly improved dynamic mechanical properties.In Chapter 3,using the mercapto-ene click reaction between TTPB and y-mercaptopropyltriethoxysilane(MPTES),by controlling the molar ratio of vinyl group to mercapto group in TTPB(1:1,1:2,1:4),the silica is modified synergistically to adjust the silica/rubber interaction.According to the analysis of the test results,when the molar ratio of TTPB to MPTES is 1:1,the TM1-NR composite has excellent static and dynamic properties.Because the combined ratio of TTPB and MPTES is too large,the silica is difficult to be uniformly dispersed due to the dense graft chain.On the other hand,because the MPTES modified group only has an alkoxy group,it cannot fully act on the modified silica,resulting in uneven dispersion of the TM4 modified silica with a group molar ratio of TTPB and MPTES of 1:4.In Chapter 4,using different group ratios(1:1,1:2)of TTPB and Si747 to synergistically modify silica,avoiding the short ethoxy groups of MPTES in the previous chapter and the larger volume effect of silica,resulting in the modification groups of the mercapto coupling agent cannot all act on the modified silica,and the modification effect is reduced.The effects of the two different group ratios on silica dispersion and rubber properties were studied,and the synergistic mechanism of the two combined use was clarified.The experimental results show that due to the synergistic effect of TTPB and Si747,TS2 with a molar ratio of TTPB to Si747 of 1:2 can connect silica particles to each other without forming a large filler network,effectively promoting the dispersibility of silica.In addition,a chemical bond between silica and rubber is established to form a strong interface effect,which can effectively increase the 300%tensile strength and reinforcement factor of the material,and enhance the wear resistance of the rubber compound.Compared with other samples,the TS2-NR rubber composite has the lowest tan? value at 60? and the lowest rolling resistance.