Preparation and Dynamic Mechanical Properties of Copolymers Based on Butadiene, Isoprene, and Styrene

The styrene-isoprene-butadiene terpolymers were prepared using n-butyl lithium as initiator, cyclohexane as solvent, tetrahydrofuran as structure modifier and tin tetrachloride as coupling agent by a method of the change addition time of structure modifier through the anionic polymerization technique. The polymerization rate of monomers, molecular weight, microstructure, tan delta and morphology of copolymers were investigated. The results showed that addition of THF had a great effect on the polymerization rate of three monomers, especially styrene, and could tune copolymer composition by using different addition time of THF; the copolymer composition could vary gradually along the chain from block copolymers (isoprene-butadiene) to gradient copolymers (isoprene-butadiene-styrene isoprene-butadiene). It resulted in broadening of glass transition region and damping range. The monomer ratio and molecular weight that affected the mechanical and dynamic mechanical properties of copolymers were also investigated. At the same time, the microstructure, morphology and mechanical properties were compared with random terpolymer and solution styrene-butadiene rubber/butadiene rubber/nature rubber blend.