Synthesis and characterization of biobased copolyesters based on pentanediol: (1) Poly(pentylene dodecanoate‐co‐furandicarboxylate)

Abstract

A series of biobased aliphatic‐aromatic copolyesters, poly(pentylene dodecanoate‐co‐furandicarboxylates) (PPeDFs) were synthesized via an esterification and polycondensation melt process. The copolyesters were characterized using gel permeation chromatography, Fourier transform infrared spectroscopy, 1H NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis, wide angle x‐ray scattering, and tensile testing. The thermal transition behavior was strongly dependent on composition, with the melting and glass transition temperatures reaching a minimum at approximately equimolar ratio of D to F. All copolyesters were stable below 300°C with their R600 (the weight of material remaining at 600°C) values increasing with F fraction. PPeD to PPeDF30 (e.g., mole ratio D/F = 7:3) show sharp PPeD crystalline reflections only while broad PPeF reflections are shown in PPeF and PPeDF90. PPeDF40 to PPeDF80 showed both crystal structures. The fractional crystallinity for the PPeD was much higher than PPeF and the fractional crystallinity of the copolymers showed a minimum at D/F ratios closer to the latter. The stress at break and modulus both exhibited maxima at D/F ratios that were either high or low, but somewhat surprisingly a strong maximum in percent elongation at break of over 600% occurs at PPeDF40. For this composition, a typical plastic behavior curve was found including a yield point, high elongation at break, and strain hardening.Highlights Poly(pentylene dodecanoate‐co‐furandicarboxylates) (PPeDFs) are synthesized Mechanical properties, a function of D:F ratio. High elongation at 40 mol% F. Two melting temperatures/crystal structures, one PPeD, the other PPeF Glass transition temperature minimum at intermediate D:F ratios