(302a) Synthesis and Characterization of Biobased Copolyesters Based on Pentanediol. Poly(pentylene adipate-co-terephthalate)

Sixty percent of household waste comes from single-use packaging. Most flexible food packaging is made of linear-low-density polyethylene (LLDPE) or low-density polyethylene (LDPE) which cannot easily be recycled, nor will it degrade in a reasonable timescale. Therefore, the development of biodegradable polymers that have similar thermal, mechanical, rheological, and barrier properties as LLDPE and LDPE for flexible film applications is highly desirable. A high molecular weight poly (pentylene adipate-co-terephthalate) with a 40/60 adipic acid/terephthalic acid mole ratio was synthesized using direct esterification and polycondensation. Thermal, mechanical, and rheological properties of the copolyesters were thoroughly investigated using different techniques, including differential scanning calorimetry, thermogravimetric analysis, wide-angle x-ray scattering, dynamic mechanical analysis, and rheometry. With sufficient molecular weight, the properties of the PPeAT copolyesters were comparable to the properties of film-grade linear low-density polyethylene making the copolyester a suitable alternative for flexible packing applications. However, the slow crystallization rate created a major challenge. A nucleating agent was added to increase the crystallization rate, decreasing the half-time crystallization from 28 minutes to 0.6 minutes.