Cleavable multiblock copolymer synthesized by ring‐opening metathesis copolymerization of cyclooctene and macrocyclic olefin and its hydrolysis to give carboxyl‐telechelic polymer

A novel cleavable multiblock copolymer was synthesized by ring‐opening metathesis polymerization (ROMP) of cyclooctene (COE) and a flexible 27‐membered macrocyclic olefin (MCO), which is acted as the spacer to collect the polymer structure block by block. MCO 2 was prepared via ring‐closing metathesis of the long chain alkyldiene, and then 2 was well‐ conducted ROMP with COE to provide the multiblock copolymer [Poly(COE)‐ 2 ] m consisting of homo‐Poly(COE) blocks and ring‐opened 2 segments with different molecular weights ( M n = 30.0 – 249.6 × 10 3 ) and polydispersity index (PDI) within 1.45–1.67 as variation of the feed ratio of COE to 2 . The multiblock copolymer chain containing weak ester linkage can be cleaved under alkali condition to afford the carboxyl‐telechelic Poly(COE) blocks with much lower molecular weights ( M n,h = 3.6–35.7 × 10 3 ) and slight higher PDIs (1.65–1.88). The average block number on multiblock copolymer chain was obtained from the ratio of M n to M n,h and was reached up to the value of 7–16.