Biobased high barrier copolyesters derived from furandicarboxylic acid and citric acid

Biobased feedstocks developed from renewable resources play a crucial role in polymers. Dimethyl octahydro2,5-pentalenediol (MeOPD) with excellent thermal stability and rigidity is a biobased bicyclic diol derived from citric acid. In this work, MeOPD was first reacted with dimethyl carbonate (DMC) to form oligo (dimethyl octahydro-2,5-pentalenediol carbonate) (OMC). Subsequently, a series of poly(butylene-co-dimethyl octahydro2,5-pentalenediol furanoate-co-carbonate) (PBMFC) polyesters with MeOPD units ranging from 5 to 31 mol% were synthesized via melt polycondensation from OMC, dimethyl furan-2,5-dicarboxylate (DMFD) and 1,4-butanediol (BDO). Due to the low reactivity of MeOPD, its actual content in copolymer is much lower than that in the feed, and as the MeOPD content rises, the number-average molecular weight of PBMFCs drops from 25,200 g/ mol of PBMFC5 to 12,800 g/mol of PBMFC31. Despite the presence of MC units weakens thermal stability, PBMFCs still maintain good thermal stability, evidenced by Td,5% ranging from 294-325 degrees C in N2 and from 295339 degrees C in air. The mechanical properties are also satisfactory, exhibiting tensile modulus >= 500 MPa, tensile strength >= 23 MPa, and elongation at break >= 150 %. Compared to PET, PBMFCs demonstrate commendable gas barrier properties, with CO2 and O2 barrier capability being 4.7-11.0 times and 2.0-3.6 times that of PET, respectively. All results indicate that PBMFCs can serve as a renewable potential material for packaging application.