Copolymerization of butadiene and styrene under the influence of n-butyllithium

Abstract

It is known that styrene-butadiene copolymers having an increased content of 1,2-links of butadiene give tires a unique combination of good grip properties and low rolling resistance. Under conditions of severe operation, heat generation, and, therefore, rolling resistance of this rubber turned out to be less than that of polymers with a conventional structure. Compared to other rubbers, SSBR rubber with a high content of carbon black (mire than 50%) is highly economical. Lower heat generation in SSBR tires is a significant advantage over other rubbers and is preferable for long-term safety of the run even in desert conditions. The growing requirements for energy saving, safety of road transport, ecology, as well as a sufficient level of scientific research in the field of ionic polymerization of monomers were prerequisites for the creation of technology for obtaining solution copolymers based on dienes and vinyl aromatic monomers with special properties based on the mathematical model of the isothermal process of copolymerization of styrene and butadiene in an aliphatic solvent on the n-BuLi/mod catalytic system, which includes four chain growth reactions, two chain transfer reactions to a transfer agent, the concentration of which is recalculated. The calculation of the copolymerization constants of styrene and butadiene in hexane in the presence of the tested catalytic system is presented and the parameters of the obtained mathematical model are determined. Compliance with the optimal mode of conducting the polymerization process makes it possible to obtain rubber with specified physical and mechanical properties. The models presented in this paper take into account the most complex mechanisms of the copolymerization process, taking into account the hydrodynamics and heat transfer in the system, as well as the features of the real technological process. For the first time, the universal approach to solving the problem of obtaining SSBR rubber with a predictable set of properties is proposed. Based on mathematical modeling, laboratory experiments and optimization of the copolymerization process, the possibility of directed synthesis of functionalized DSSC rubber with the required physical and mechanical characteristics has appeared.