Ring-opening copolymerization of ε-caprolactone and δ-valerolactone by Titanium-based metal-organic framework.

Metal organic frameworks (MOFs) are not much investigated as catalysts in copolymer formation with cyclic esters. Herein, we report the ring-opening copolymerization of e-caprolactone (CL) with δ-valerolactone (VL) using a recoverable and reusable Ti-metal based MOF, MIL-125 without any co-catalyst in a solvent-free medium. The synthesized copolymers are random in nature, exhibit lower crystallinity than those of the corresponding homo-polymers, and are totally free from metal contamination, which was established by a series of appropriate experiments and characterization techniques.