Difunctional Initiators Based on 1,3-Diisopropenylbenzene. 3. Synthesis of a Pure Dilithium Adduct and Its Use as Difunctional Anionic Polymerization Initiator

The addition reaction of tert -butyllithium ( t -BuLi) to 1,3-diisopropenylbenzene (1,3-DIB) has been studied. Under optimized conditions, i.e., reaction in cyclohexane at −20 °C and dropwise addition of 1,3-DIB to a 1:1 t -BuLi−triethylamine (Et 3 N) complex followed by a 1 h postreaction period, a pure diadduct is formed without concomitant oligomerization of 1,3-DIB. The behavior of this diadduct has been investigated, in apolar and polar solvents; triblock copolymers have been prepared and found to have interesting mechanical properties.