High Molecular Weight Polyesters Derived from Biobased 1,5-Pentanediol and a Variety of Aliphatic Diacids: Synthesis, Characterization, and Thermo-Mechanical Properties

High molecular weight aliphatic polyesters were synthesized from biobased 1,5-pentanediol and aliphatic diacids with 4, 5, 6, 9, 10, or 12 carbon atoms via melt polycondensation. The poly(1,5-pentylene dicarboxylate)s were characterized with intrinsic viscosity, gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), and tensile testing. The effects of dicarboxylate chain length on crystalline structure and thermo-mechanical properties were investigated. All the polyesters had weight-average molecular weight over 100,000 g/mol or intrinsic viscosity over 1.05 dL/g except poly(1,5-pentylene adipate) (PPeA), which was less thermally stable than others. As semicrystalline polymers, they have a polyethylene-like crystal structure and crystallize rapidly except poly(1,5-pentylene succinate) (PPeS). As a whole, the crystallizability and melting temperature (Tm) increase with dicarboxylate chain length, and the “even–odd” effect exists to a certain extent. Among them, poly(1,5-pentylene azelate) (PPeAz), poly(1,5-pentylene sebacate) (PPeSe), and poly(1,5-pentylene dodecanedioate) (PPeDo) have Tm of 50–62 °C, good thermal stability, and exhibit comparable or even superior tensile properties in comparison with polyethylene and the well-known biodegradable copolyester, poly(butylene adipate-co-terephthalate) (PBAT). These biobased and potentially biodegradable polyesters appear to be promising materials for practical applications.