Styrene → Benzene, ethenyl-, polymer with 1,3-butadiene

Participants

Reaction Steps

920 g of styrene, 80 g of butadiene, and a premixed catalyst solution comprising 0.1 ml of a 1 molar s-butyllithium solution in cyclohexane and 0.6 ml of a 1 molar dibutylmagnesium solution in n-hexane were added simultaneously over a period of one hour to a 2 l stirred reactor and polymerized at 70° C. The reaction mixture was held at 70° C. beyond the color change from yellow to red. At a solids content of 9.6% by weight, the reaction was stopped using 1 ml of a 1:1 mixture of methanol and ethanol. This gave a viscous solution of a butadiene-styrene block copolymer having a residual butadiene content of 1720 ppm and a molecular weight of Mn=137,000.

Provenance & Evidence