Sustainable terpolyester of high Tg based on bio heterocyclic monomer of dimethyl furan-2,5-dicarboxylate and isosorbide

Sustainable biobased terpolyester based on heterocyclic dimethyl furan-2,5-dicarboxylate and isosorbide in combination with ethylene glycol and 1,4-cyclohexanedimethylene (PEICF) were successfully synthesized by two-step melt polymerization method and characterized. A series of PEICF terpolyester exhibited excellent heat resistive properties, with glass transition temperatures of 81-119 degrees C, and high molecular weights (Mw = 50,800 g mol(-1)). When esterification was carried out at fixed a COOH:OH molar ratio of 1:2, 1,4-cyclohexanedimethanol (CHDM) showed increased reactivity compared to isosorbide (ISB) and ethylene glycol (EG) monomers. As a result, EG was most likely to be placed at the end of the oligomer chains, which accelerated the transesterification process and drastically increased chain growth via chain scission at the carbonyl carbon adjacent to the ethylene unit due to steric hindrance. The zero shear viscosities of the PEICF terpolyester were much higher than that of the copolyester and increased with increasing ISB content. This study proposed a method for improving the low reactivity of dimethyl furan-2,5-dicarboxylate, which shows suppressed furan ring flipping, with sterically hindered ISB by using highly reactive CHDM at atmospheric pressure. These results signify the importance of controlling the synthetic conditions, as they affect the composition of the polymer backbone due to the different reactivities, volatilities, and steric hindrances of the monomers. (C) 2017 Elsevier Ltd. All rights reserved.