Design And Synthesis Of Wide Temperature Range Damping Rubber

The polymer damping materials is a hot research at home and abroad in the field of vibration and noise reduction all the time. Because the rubber has the characteristics of small elastic modulus, varieties and superior damping performance, which plays the important role in the polymer damping materials and has great research value and using value. Generally speaking, the glass transition temperature rang of random copolymer or homopolymers only 20～30℃, so the effective damping temperature rang is probably in the vicinity of the glass transition temperature(Tg) ±(10～15)℃.As for the Tg of rubber damping materials are generally below room temperature, so they cannot be used alone. In practical application, not only to ensure that the Tg and the use of temperature material to adapt, but also should try to widen the effective damping temperature range of materials. Based on this study, A series of different structure styrene isoprene rubbers(SSIR) were synthesized by using styrene and isoprene, n-butyl lithium, the mixed solution of cyclohexane and n-hexane, tetrahydrofuran, and tin tetrachloride as monomer, initiator, solvent, structure modifier and coupling agent respectively with anionic polymerization technology. And study its mechanical properties and damping properties.First, in the initiation temperature of 50℃, different mole ratio of THF/Li system, study on the reaction kinetics of styrene, isoprene copolymers. Research shows that, with the increase of THF/Li mole ratio, the reaction rate and the two monomer reaction rate increased, the THF/Li is greater than 20, the rate of the reaction of styrene monomer greater than the reaction rate of isoprene monomer. The results laid the foundation for the preparation of random SSIR and block SSIR.Second, random SSIR were synthesized with different structure by using a feeding method, which were characterized by gel permeation chromatograph(GPC), nuclear magnetic resonance(1H-NMR), and differential scanning calorimetry(DSC), dynamic mechanic analysis(DMA). The experiment investigates the effects of different THF/Li molar ratio, St contents, molecular weight on the microstructure, mechanical properties, dynamic mechanical properties of SSIR. In the middle of vinyl side groups content, we achieve the high damping rubber materials with the peak of loss factor reaching 1.1.Third, block SSIR were synthesized with different structure by using a feeding and delay adding regulator(THF) method, which were characterized by’H-NMR, GPC, DSC, DMA. The experiment investigates the effects of THF addition time, St contents, molecular weight on the microstructure, mechanical properties, dynamic mechanical properties of SSIR. we obtained wide temperature damping rubber with the effective damping temperature range of-25℃～25℃.Last, block SSBR were synthesized with different structure by using a feeding and delay adding regulator(THF) method, which were characterized by 1H-NMR, GPC, DSC, DMA. The experiment investigates the effects of THF addition time, St contents, molecular weight on the microstructure, mechanical properties, dynamic mechanical properties of SSBR. We achieve the damping rubber with the effective damping temperature range of -40～0℃,in a low region. Compared to SSIR, the effective damping temperature of SSIR is wider than SSBR.