Bench-Scale Synthesis and Characterization of Biodegradable Aliphatic–Aromatic Random Copolymers with 1,4-Cyclohexanedimethanol Units Toward Sustainable Packaging Applications

The development of biodegradable packaging films can resolve environmental issues caused by plastic waste, but it still remains a great challenge to develop economically feasible polymers that simultaneously balance robust mechanical properties, biodegradability, and transparency. In this work, we describe the bench-scale synthesis (∼1.5 kg) and blown film characterization of new biodegradable aliphatic–aromatic copolymers, poly­(1,4-butylene-1,4-cyclohexanedimethylene carbonate–terephthalate)­s (PBCCTs) with different molar ratios of two diol monomers, 1,4-cyclohexanedimethanol (CHDM) and 1,4-butandiol (BD), from 0:1 to 5:5 (CHDM/BD) to optimize the mechanical, optical, and thermal properties and biodegradability. The incorporation of CHDM units significantly impacted the thermal properties of the blown films from these copolymers; PBCCT films with 50 mol % CHDM content had a more amorphous and glassy character compared with the films with 0 mol % CHDM. And, PBCCT films with 30–50% CHDM content exhibited superior mechanical properties (tear strength = 11.5 kgf/mm and tensile strength = 369 kgf/cm²) and comparable transparency (haze = 16%) to those of nondegradable polyethylenes (PEs), the most commonly employed materials for packaging film applications. Taken together, the bench-scale synthesis of biodegradable polymers with suitable thermomechanical, optical, and permeability properties presented here showcases the potential of these materials as sustainable packaging materials.