Styrene → Styrene-butadiene-styrene

Participants

Reaction Conditions

Reaction Steps

45 l of cyclohexane and 3 kg of styrene are introduced into a 100 l reactor fitted with wall cooling and additionally an external heat exchanger (tube-bundle heat exchanger) supplied by a pump, titrated against a 12% strength solution of sec-butyl-lithium in hexane until a pale red coloration remains and heated to 40° C. 140 ml of a solution, 12% strength in overall terms, of a mixture of 1 part by weight of s-butyllithium and 4 parts by weight of dibutylmagnesium in hexane are then added. The temperature remains at 40° C. A mixture of 14 g of butadiene and 3 kg of styrene is then added. Under these conditions, the temperature rises to 53° C. within 30 minutes. The styrene-butadiene-styrene block copolymer obtained has a tear strength of 24 MPa in the DIN 53455 tensile test. A molecular weight MW of 125,000 and a nonuniformity MW/MN of 1.15 are measured.

Provenance & Evidence