High thermal resistance amorphous copolyesters synthesized from bio‐based 2,5‐furandicarboxylic acid

The polyesters with high Tg (≥100°C) and good clarity are desired in fabricating heat‐resistance containers such as baby bottles, cups, medical apparatus, and kitchen appliances. In this work, a series of poly(butylene bis[4‐(2‐hydroxyethoxy) phenyl] sulfone 1,4‐cyclohexanedimethylene 2,5‐furandicarboxylate) (PBSCFs) that show superior thermal and mechanical properties against current bio‐based polyesters were synthesized via a melt polycondensation method. The accurate chemical structures of PBSCFs were confirmed by 1H‐NMR and 13C‐NMR. The SEC results show that PBSCFs have number averaged molar mass (Mn) in the range of 9700–28,500 g/mol. The Tg of PBSCFs increase from 94°C for PBSF to 108°C for PBSCF‐50 as the increasing of CHDM unit. Meanwhile, the ductility of PBSCFs also improved with the elongation at break of PBSCF‐40 increased to 223%. In addition, the PBSCF‐40 sample reported in this paper shows thermal decomposition temperature of 427°C, transmittance of 84.6%, haze of only 0.17%, tensile strength of 74.1 MPa, and tensile modulus of 2287 MPa.