Synthesis of hydroxytelechelic e-caprolactone/poly(ethylene terephthalate) co-oligomers, 1

In the presence of ethylene glycol, poly(ethylene terephthalate) (PET) undergoes chain scissions with the formation of α,ω-hydroxyl oligomers, through classical transesterification by alcoholysis. e-Caprolactone was subsequently added on the hydroxyl end groups of PET oligomers by ring-opening polymerization at different molar ratios of e-caprolactone to PET oligomers. The chemical structure of the products was investigated by size exclusion chromatography, 1 H NMR spectroscopy, and differential scanning calorimetry. A large majority of these products are soluble in common organic solvents. The thermal and 1 H NMR analyses reveal that the transesterification between base units of PET oligomers and e-caprolactone during the synthesis is always present whatever the reaction conditions. This phenomenon leads to copolymers having thermal properties different from those of PET. However, some cooligomers present the interest of keeping properties close to those of PET. The main purpose of this study was the synthesis of PET co-oligomers that are soluble in some organic solvents that would make their use easier, and so that they can be used further as hard segment precursers for polycondensation reactions.