Nonisothermal Crystallization Kinetics as a Probe for Molecular Interactions in Biobased Semiaromatic Polyester. The Effect of Furan, Thiophene, and Benzene Ring

The development of sustainable polymers with tailored functional properties is a key challenge in the transition toward environmentally friendly materials. Among biobased polyesters, furan- and thiophene-containing polymers have gained attention due to their promising mechanical and barrier properties, which have been linked to noncovalent interchain interactions such as pseudohydrogen bonding, pi-pi stacking, and dipole-dipole interactions. Kinetic studies can be used as a probe for evaluating the effect of such interactions on crystallization. In this study, the crystallization behavior, both from the glass and the melt, of two polyesters, poly(butylene 2,5-furandicarboxylate) and poly(butylene 2,5-thiophenedicarboxylate), obtained by reacting the above-mentioned diacid with butanediol, was investigated through nonisothermal DSC experiments. A third polyester, poly(butylene isophthalate), was also studied for the sake of comparison. Data were analyzed through an approach based on Hoffman-Lauritzen theory adapted to nonisothermal experiments using the isoconversional principle. The crystallization process was then modeled to validate the results while obtaining additional parameters and information regarding the crystallization mechanism. Findings highlighted a correlation between kinetics-related quantities and molecular features that relate to interchain interactions, confirming the validity of using crystallization kinetics as a probe for molecular interactions.