Superior barrier performance, mechanical properties and compostability in relation to supramolecular structure of renewable based poly(trimethylene furanoate) modified with suberic acid

Here, 100% bio-based aliphatic/aromatic copolyesters of 2,5-furandicarboxylic acid (FDCA) were synthesized via two-stage melt polycondensation combining different ratios of FDCA and suberic acid with 1,3-propanediol. The prepared copolymers were characterized from the molecular point of view and processed into free-standing thin films. Afterward, the films were subjected to structural and thermal characterization. The mechanical response and barrier properties to O2 and CO2 were evaluated. PALS measurements were also performed to estimate free volume fraction in the samples. Then composting experiments at lab scale were carried out. The results indicated that the tuning of aliphatic co-unit content is an effective tool to modulate the chain mobility and, in turn, the kind and fraction of ordered phases developed in the samples. In addition to the usual amor- phous and 3D crystalline phase, a further phase, characterized by a lower degree of order than the crystalline one, is present, whose amount is strictly related to copolymer composition. The relative fraction of all these phases is responsible for the different mechanical and barrier performances and biodegradation kinetics. Last but not least, a comparison between the copolymers under study and poly(trimethylene furanoate/sebacate) copo- lyesters previously investigated by the Authors was carried out.