Electrospun Poly(butylene 2,5-furanoate) and Poly(pentamethylene 2,5-furanoate) Mats: Structure–Property Relationships and Thermo-Mechanical and Biological Characterization

This study explores, for the first time, the application of electrospun biobased poly(butylene 2,5-furanoate) (PBF) and poly(pentamethylene 2,5-furanoate) (PPeF) mats in biomedical and drug delivery fields, through a careful investigation of their structure–property relationship. PBF mats, with a glass transition temperature (T_g) of 25–30 °C and an as-spun crystallinity of 18.8%, maintained their fibrous structure (fiber diameter ~1.3 µm) and mechanical properties (stiffness ~100 MPa, strength ~4.5 MPa, strain at break ~200%) under treatment in physiological conditions (37 °C, pH 7.5). In contrast, PPeF mats, being amorphous with a T_g of 14 °C, underwent significant densification, with geometrical density increasing from 0.68 g/cm³ to 1.07 g/cm³, which depressed the specific (i.e., normalized by density) mechanical properties. DSC analysis revealed that the treatment promoted crystallization in PBF (reaching 45.9% crystallinity), while PPeF showed limited, but interestingly not negligible, structural reorganization. Both materials promoted good cell adhesion and were biocompatible, with lactate dehydrogenase release not exceeding 20% after 48 h. The potential of PBF mats for drug delivery was evaluated using dexamethasone. The mats exhibited a controlled drug release profile, with ~10% drug release in 4 h and ~50% in 20 h. This study demonstrates the versatility of these biopolyesters in biomedical applications and highlights the impact of polymer structure on material performance.