Sustainable Polymers from Renewable Resources: Polymer Blends of Furan-Based Polyesters

A series of blends of furan-based green polyesters, for eco-friendly packaging materials, are synthesized. Poly(ethylene 2,5-furandicarboxylate) (PEF), poly(propylene 2,5-furandicarboxylate) (PPF), and poly(butylene 2,5-furandicarboxylate) (PBF) are synthesized by applying melt polycondensation. Blends of the above polyesters with 50/50 w/w composition as well as blends of furanoate/terephthalate (PPF/PPT) are also prepared. The glass temperature along with the crystallization and melting behaviors of melt quenched blends are studied aiming at understanding their dynamic state and miscibility. Based on their T-g and crystallization behavior, PEF/PPF shows dynamic homogeneity and miscibility whereas PPF/PBF and PEF/PBF exhibit partial miscibility and immiscibility, respectively. In an effort to dynamically homogenize the compounds, reactive blending is applied and the behavior of the resulting blends is monitored following quenching. A profound improvement in blend homogenization is observed with increasing melt mixing time for the PPF/PPT sample, evidenced by the single glass temperature and by the narrowing in liquid-to-glass regime. The obtained single glass temperature together with the suppressed tendency for crystallization with increasing mixing time are taken as evidences of dynamic and thermodynamic homogeneity.