?-Caprolactone/ZnCl2 complex formation: Characterization and ring-opening polymerization mechanism

Synthesis and characterization of poly(ε-caprolactone) and copolyesters by catalysis with molybdenum compounds: polymers with acid-functional asymmetric telechelic architecture

“…This methoxy end group comes from methanol, which was used for recrystallization of the polymer. Acylation of methanol apparently requires the presence of an acid chloride end group (R-CO-Cl) in the original polymer chains, (2) -CH 2 -OH (b, d 3.63 1 H and 62.2 13 C) formed by reaction with water [21], (3) -CH 2 -Cl (c, d 3.52 1 H and 44.5 13 C) formed by chlorination of methylene attached to oxygen [22], (4) -CH 2 -O-CH 2 -(d, d 3.37 1 H and 70.4 13 C) probably formed by a nucleophilic attack of an alkoxide to the methylene in the epsilon position of CL [23]. Also, peaks for olefinic protons -CHaCH 2 (d 5.75 and 4.98) due to a dehydration reaction of hydroxyl end groups were observed.…”

Microwave‐assisted ring‐opening polymerization of ϵ‐caprolactone

“…PCL is generally prepared from catalyzed ring‐opening polymerization (ROP) of ϵ‐caprolactone in bulk or solution 6. In the last decade, many efforts were devoted to improving ROP by developing catalysts, and many compounds containing aluminum, tin, zinc, and rare‐earth metals were investigated 7–15. Kowalski et al9 investigated the kinetics of the polymerization of ϵ‐caprolactone initiated by stannous octanoate [Sn(Oct) 2 ] in tetrahydrofuran at 80 °C; the results strongly suggested that the tin alcoholate active centers were formed from the starting carboxylate, and the polymerization proceeded on the tin‐alkoxide bond.…”

Microwave‐Assisted Ring‐Opening Polymerization of ε‐Caprolactone in the Presence of Ionic Liquid

“…Zinc and its related compounds are oligoelements that are required daily by the normal metabolism of mammalian bodies 37. Zinc metal,38 zinc chloride,39 zinc lactate,40–42 and zinc alkoxides43 have been used as catalysts in the ROP of lactones and lactides. In this work, ZnO has been selected as the catalyst for the MROP of ε ‐CL.…”