Technological watch

This work contributes to develop bioplastics with high gas barrier properties. Here we reported a new bio-based semi-aromatic polyester poly(decylene 2,6-pyridinedicarboxylate) (PDePD26) for food packaging applications, synthesized from 2,6-pyridinedicarbonyl dichloride (PDD26) and 1,10-decanediol (DD) by a traditional polycondensation reaction. Two analogs, poly(decylene 2,5-pyridinedicarboxylate) (PDePD25) and poly(decylene isophthalate) (PDeIP) were also synthesized. The obtained polyesters were confirmed semicrystalline with Mw? higher than 50 000 g mol?1. The structure polarity and geometric symmetry of the aromatic moieties revealed to be efficient tools to tailor the ability of crystallization, and then affect thermal, mechanical and transport performances. The polyesters containing pyridine rings (PDePD26 and PDePD25) showed lower thermal degradation temperatures (341 and 304 °C) than the one containing phenyl rings (PDeIP, 371 °C), but Tg, Tm and crystallinities were higher. PDePD26 displayed the preferred mechanical strength (?b = 12.5 ± 4.8 MPa) and elongation (?b = 25.0 ± 6.0%) at break. The highest gas barrier properties of PDePD26 were much better than PLA and comparable to amorphous PET.