Study On Hydrogenation And Properties Of SBR And NBIR

The liner random copolymer Styrene-Butadiene Rubber was synthesized by living anionic polymerization method using cyclohexane as solvent, THF as structure modifier, and Rli as initiator. There are several benefits of using THF as structure modifier. First it can improve the content of 1,2-PB unit up to 55%. Second it can be used to adjust reactivity ratios of styrene and butadiene for synthesizing random SBR. Finally the structure modifier does not effect the hydrogenation reaction. The detailed parameters obtained by'H-NMR and GPC indicate that the products fit well with the characteristics of the anionic polymerization. Effect of monomer ratios and microstructure of SBR on the physical mechanical properties was studied.Both industrialized SSBR and self-made SBR were hydrogenated by naphthenate nickel (Ni) as based catalyst, triisobutyl aluminum (Al) as cocatalyst. The reaction conditions:Ni dosage of 2mg/g, Al/Ni of 6, hydrogen pressure of 4Mpa, reaction temperature of 60℃. The hydrogenation degree was controlled by the reaction time. The effect of hydrogenation degree on tensile properties, anti-aging properties and dynamic mechanical properties was investigated in detail. The results showed that hydrogenation could improve the aging resistance of SBR. The breaking elongation of products would increase significantly with the increase of the hydrogenation degree, while the breaking strength decreased. DMA analysis showed that the dynamic mechanical properties were independent of the hydrogenation degree.The self-made acrylonitrile-butadiene-isoprene random terpolymer (NBIR) dissolved in toluene was hydrogenated with RhCl(PPh3)3 catalyst system. The effects of reaction temperature and amount of catalyst on the hydrogenation reaction were studied. This catalyst system has the highest reactivity when the temperature was 145℃, the reaction pressure was 3 Mpa, the amount of catalyst was 0.45%(weight of dry rubber). The copolymer was characterized by H-NMR, FT-IR, TGA and DSC. The results showed that the olefin double bonds were selectively reduced, and the oil-resistance group (-CN) was not hydrogenated by RhCl(PPh3)3 catalyst system. The initial decomposition temperature and aging resistance of hydrogenated product improved significantly compare to the original polymer.