Well-defined diblock macromonomer with a norbornene group at block junction: Anionic living linking synthesis and ring-opening metathesis polymerization

A living linking method for the preparation of diblock macromonomer and its transformation into coploymers was reported. The first step of macromonomer synthesis involved the preparation of a poly(styryl-d₈)lithium by anionic polymerization of styrene-d₈ (St-d₈) using sec-butyllithium (s-BuLi) as initiator in benzene at room temperature ([St-d₈]₀:[s-BuLi]₀ = 10.0). The next step of involved the addition reaction of a solution of poly(styryl-d ₈)lithium with an excess of norbornene 1,1-diphenylethylene (DPE) (1.27equiv) that was conducted at -78° C in THF for 1 h to obtain norbornene-functionalized poly(St-d₈)-based 1,1-diphenylalkyllithium. The deuterated chlorofoam was used as the polymerization solvent to monitor the ring-opening metathesis polymerization (ROMP) process by using ¹H NMR spectroscopy.