Poly(ethylene 2,5-furandicarboxylate-mb-poly(tetramethylene glycol)) multiblock copolymers: From high tough thermoplastics to elastomers

Poly(ethylene 2,5-furandicarboxylate) (PEF) is a biobased polyester with superior thermo-mechanical and gas barrier properties than poly(ethylene terephthalate) (PET), the most widely used petroleum-based polyester. However, PEF is more brittle than PET. To toughen PEF, a series of P(EF-mb-PTMG) (PETF) multiblock copolymers with high intrinsic viscosity were successfully synthesized via melt polycondensation in the presence of poly(tetramethylene glycol) (PTMG) oligomer diols, and characterized with FTIR, H-1 NMR, DSC, WAXD, TGA and SEM, and assessed with tensile and impact testing. The presence of PTMG contributes to promote intrinsic viscosity growth and depress etherification and discoloration side reactions. The PTMG flexible segments show chain length dependent partial miscibility with PEF hard segments, and its presence also plasticizes and promotes cold crystallization of PEF segments. With tuning the PTMG content, high performance PEF-based materials can be tailor-made from high tough thermoplastics with excellent ductility and impact toughness to thermoplastic elastomers with high strength. Particularly, (PETF)-F-1K-20 shows excellent ductility (elongation at break 252%) while retaining high modulus (3.0 GPa) and yielding strength (74 MPa), and (PETF)-F-1K-35 is the first PEF-based material with impact strength over 50 kJ/m(2) to date.