High Temperature Bulk Reaction between Poly(ethylene terephtalate) and Lactones: ¹H NMR and SEC/MALDI‐TOF MS Study

Abstract

Summary: Copolyesters containing aliphatic units in the main chain were obtained by reacting high molar mass poly(ethylene terephthalate) (PET) with ε‐caprolactone or δ‐valerolactone at high temperature in the bulk. γ‐Butyrolactone did not react in these conditions. Thermal properties were studied by DSC and TGA, and structural characterizations were carried out by 1H NMR spectroscopy and SEC/MALDI‐TOF mass spectrometry off‐line coupling. These techniques demonstrate the insertion of lactone units in PET chains. Linear species with hydroxy, carboxy and vinyl ester end‐groups were clearly identified in the mass spectra, together with cyclic copolymer species. Narrow‐distribution copolyester SEC fractions were characterized by MALDI‐TOF mass spectrometry and used to establish a SEC calibration curve against absolute molar masses. The results indicate that the conventional polystyrene SEC calibration strongly overestimates copolyester molar masses. The degree of randomness of these copolyesters, determined by 1H NMR, shows that chain microstructure presents some block‐copolymer character. The thermal properties of the copolyesters are also discussed.Reaction between PET and γ‐butyrolactone (x = 3), δ‐valerolactone (x = 4), or ε‐caprolactone (x = 5).magnified imageReaction between PET and γ‐butyrolactone (x = 3), δ‐valerolactone (x = 4), or ε‐caprolactone (x = 5).

Poly(ethylene‐co‐1,4‐cyclohexylenedimethylene terephthalate) copolyesters obtained by ring opening polymerization

“…As a consequence, ROP is starting to be considered a serious alternative to the traditional polycondensation method for the preparation of the most-extensively used aromatic polyesters. The ROP method has been successfully extended to the synthesis of copolyesters made up of aromatic and aliphatic units as PET with lactones [21,22] and lactides, [23] poly(butylene terephthalate-co-caprolactone), [24] and poly(hexamethylene-co-caprolactone) [25] prepared from ecaprolactone and cyclic oligomers of butylene terephthalate and hexamethylene terephthalate, respectively. A valuable up-dated account of the synthesis and polymerization of cyclic oligoesters has recently been reported by Brunelle.…”

High temperature reaction between poly(glycolic acid) and ε-caprolactone in ionic liquids

“…However, the precipitation of PGA in reaction medium at long reaction times limited the achievable molar mass. Since reacting polyesters with ε-caprolactone monomer (CL) is an efficient way of copolyester synthesis [37], this work reports on the reaction between CL monomer and a PGA oligomer carried out in BMIm + Tf 2 N -and BMIm + BF 4 -ionic liquids, to obtain copolyesters exhibiting better solubility. The incorporation of CL units in PGA chains and the changes in copolyester microstructure under various reaction conditions were followed by NMR spectroscopy and DSC analyses.…”

Furanic‐Aromatic Copolyesters by Interchange Reactions between Poly(ethylene terephthalate) and Poly[ethylene 5,5′‐isopropylidene‐bis(2‐furoate)]

“…In previous works, we reported the synthesis of PETaliphatic polyester copolymers by the bulk reaction of PET with e-caprolactone, d-valerolactone, [15] and cyclodi(ethylene succinate), [16] showing that this method is both a very easy and efficient way to produce such copolyesters. On the other hand, the melt blending of PET, or its homologs, with aliphatic polyesters has been described to yield potentially biodegradable copolyesters, e.g., by reacting PET or poly(butylene terephtalate) with poly(butylene succinate), [13,17] poly(butylene adipate-co-succinate), [6] poly(butylene glutarate-coadipate-co-succinate), [18] poly(ethylene adipate), [19] or poly(ecaprolactone).…”