Study On High Trans-polybutadiene Rubber By Anionic Polymerization

For the purpose of saving energy, new type of tread rubber should be developed in automobile industry. The research focus is reducing roll resistance on the premise of keeping abrasion resistance and wet traction, thus achieving the unity of Economy and Safety of tire. Recent years along with the understanding on the Correlation of Structure and Property deepen increasingly, it is found that HTPB, which has good stretching stress, high-hardness, good abrasion performance, good fatigue resistance and high Tensile Strength, should be used as compounding rubber in tire retread industry for improving tire performance. So it is the ideal material for developing radial tire.The research of high trans-1,4-polybutadiene has started for a long time at abroad, but various synthetic methods exist different disadvantage which is bad for actual production. Synthesis of the high trans-1,4-polybutadiene by anionic polymerization develops deeply and gains ground of late years, but it has not been studied in China.BaDEGEE and BAT were synthesized in this paper at first, and then high trans-1,4-polybutadiene was synthesized with n-BuLi-TIBA-organic barium compound catalyst system and cyclohexane as the solvent. The effect on polymerization reaction and polymer with the catalyst system is systematacially studied in this paper, and the polymerization kinetics of butadiene is determined by dilatometer method. The microstructure, Tg, molecular weight and molecular weight distribution of HTPB were analyzed and characterized by using FT-IR, DSC, GPC and other apparatus. It was found that:HTPB had been synthesized with n-BuLi-TIBA-organic barium compound catalyst system. The trans-1,4-structure content should be controlled by adjusting the dosage of catalyst and the polymerization temperature. The trans-1,4-structure content increased gradually with increasing the ratio values of Al/Li, and the rate of polymerization reaction decreased at the same time; the rate of polymerization reaction increased gradually with the rise of the temperature, and trans-1,4-structure content decreased at the same time; the rate of polymerization reaction and trans-1,4-structure content decreased with the increase of THF/Li. HTPB crystallized when the trans-1,4-structure content exceeded 80%, and the crystallinity increased with the increase of trans-1,4-structure content; HTPB could be coupled by SiCl₄, but coupling efficiency was low.On the other hand, the medium trans-high trans block polybutadiene was synthesized. And it was confirmed that the polymer was block polymer but not blend polymer by further analysis. HTPB had a Tg which appeared at -90℃-80℃and the block PB had two Tg which appeared at -100℃～90℃and -60℃～50℃. HTPB was synthsized with functionalized lithiun catalyst including nitrogen instead of n-BuLi.