ω-Norbornenyl Macromonomers: In Situ Synthesis by End-Capping of Living Anionic Polymers Using a Norbornenyl-Functionalized α-Phenyl Acrylate and Their Ring-Opening Metathesis Polymerization

Abstract

An operationally simple approach to preparation of ω-norbornenyl macromonomers (MMs) is reported. Reaction of exo-N-(6-hydroxyhexyl)-5-norbornene-2,3-dicarboximide or exo-N-(10-hydroxydecyl)-5-norbornene-2,3-dicarboximide with α-phenyl acrylate (α-PhA) led to novel end-capping agents, NBxPhA [x is 6 (n-hexyl) or 10 (n-decyl)]. Living anionic polymerization of styrene and methyl methacrylate followed by capping with NBxPhA yielded the desired MMs, ω-norbornenyl polystyrene (NBxPS) and ω-norbornenyl poly(methyl methacrylate) (NBxPMMA). These MMs, formed with controlled molecular weights (Mn = 2–5 kDa) and low dispersity (Đ = 1.02–1.07), upon ring-opening metathesis polymerization (ROMP) resulted in P(NB-g-PS) and P(NB-g-PMMA) bottlebrush homopolymers with ∼95% and ∼75% yield, respectively, signifying efficient end-capping efficiency. The factors affecting synthesis of NBxPS and NBxPMMA and their subsequent ROMP, such as [NBxPhA]/[sec-BuLi] ratio, the length of alkyl spacer, and varying molecular weights of ...