Block Copolymers by high temperature oligomer‐coupling reactions: Bis(5‐oxazolinone)/OH reaction

High temperature chain‐coupling reactions in the bulk between amino‐, hydroxy‐ or carboxy‐terminated polymers and various coupling agents have been studied and applied to the synthesis of copolymers with aliphatic polyester, polyether or polyamide blocks. Thus, carboxy‐terminated oligomers can be coupled by bisoxazolines or bisimidazolines, while 4‐substituted and 4, 4‐disubstituted bis(5‐oxazolinones) are efficient coupling agents for amino‐ or hydroxy‐terminated oligomers. In the latter case, the use of a catalyst is necessary. The reaction has been optimized using a series of bisoxazolinones deriving from α‐amino‐acids and 1‐dodecanol and α, ω‐dihydroxy‐poly(ϵ‐caprolactone) as model compounds. High molar mass poly‐ϵ‐caprolactone containing α‐aminoacid moieties has been obtained in the presence of tetrabutoxytitanium as a catalyst.