Abstract
Abstract
Furanic polyesters were prepared by the bulk polycondensation of 5,5'- isopropylidene-bis(2-furoic acid) with 1,2-ethanediol, 1,4-propanediol and 1,6- hexanediol, and were characterized by size exclusion chromatography, NMR and MALDI-TOF MS. The ring-closing depolymerization of these polyesters was then investigated at 10 g/L concentration in 1-methylnaphthalene at 130 - 240°C. Chain flexibility, the use of zinc diacetate catalyst and, particularly, the presence of hydroxy end-groups were found to be favourable factors for the formation of high yields of cyclic oligoesters. A side reaction leading to the formation of non-reactive furyl-terminated species took place when the reactions were carried out at high temperature (240°C), limiting the yield of cyclic oligoesters.