Rare Earth Catalytic Butadiene - Isoprene Copolymer

The synthesis of butadiene-isoprene rubber bulk polymerized with rare earth catalyst has been studied experimentally in this paper. A new kind of rubber, which can be used to produce high performance tyre, was developed with different catalyst proportions and polymerization process techniques. The lab scale and pre-pilot scale tests were made, and the copolymer was analyzed and characterized. Finally the conceptual design was completed.The experimental study of rare earth catalyst was made to investigate and optimize the synthesis conditions. The catalyst appraisal method was established and the optimal conditions for the preparation of rare earth naphthenate were obtained.Lab scale tests were made for butadiene-isoprene rubber bulk polymerization. The feasible polymerization conditions were determined by studying the influences of different catalyst feeding sequential, aging time, aging concentration, aging temperature, catalyst proportion, catalyst amount, solvent, polymerization temperature and time. Meanwhile, the reactivity ratio of the two monomers and the influences of the copolymer on low temperature performance were also studied. From the analysis of microcosmic structure, there was only one Tg (-900C) for the butadiene-isoprene copolymer, and the copolymer held very high low temperature performance, can be used at -400C for a long term.Pre-pilot scale tests for butadiene-isoprene rubber copolymerization were also made. The amount of catalyst affected by test scale was studied, as well as dynamic viscosity of glue, monomer and solvent recovery. The catalyst dosage decreased remarkably with the scale up of reactor. However, the somewhat decreases of catalyst concentration would not influence the activity of polymerization. Because the concentration of monomer had a strong impact on the dynamical viscosity, it must be restricted close to 100 g/l. When the convection ratio exceeded 80%, the flow performance of rubber glue was still good and the polymerization process maintained smooth.The rheological performances of the copolymer glue were investigated to measure its rheological behavior, determine the fluid properties of butadiene-isoprene rubber glue polymerized with rare earth catalyst. The apparent viscosity of the glue was obtained and compare with that of cis-1 ,4-polybutadiene rubber. With the prolongation of the reaction time and increase of convection ratio, the viscosity of glue would be go up observably Meanwhile, with the temperature increasing, the non-Newtonian performance will be decrease.The performances of butadiene-isoprene rubber, i.e., the basic compounding and tyre tread compounding, were evaluated systematically. When it substituted for cis1 ,4-polybutadiene rubber and natural rubber, butadiene-isoprene rubber can obviouslyIIimprove the fatigue resistance, such as resistance to ripping, cured stocks, besides the excellent performances of cis- 1 ,4-polybutadiene rubber.The results of this paper have great significance to the butadiene-isoprene rubber development, cis- 1 ,4-polybutadiene performance improvement, filling up the gap of domestic rubber species as well as exploiting its commercial application market.