Tailoring Aliphatic–Aromatic PBAT Copolyesters for Melt‐Blown Biodegradable Nonwovens

ABSTRACT The escalating environmental burden caused by nondegradable polymers in disposable nonwoven products has driven the exploration of sustainable, biodegradable alternatives. This study synthesizes a series of aliphatic–aromatic copolyesters (PBA/PBT/PBAT) by varying the molar ratio of terephthalic acid (PTA) to adipic acid (AA) (1:9/3:7/5:5/7:3/9:1), systematically investigating the effect of composition on chemical structure, molecular weight, thermal behavior, and rheological properties. By controlling polycondensation end‐points, virgin PBAT copolyesters with high‐melt flowability (MFR > 40 g/10 min) and appropriate melting temperatures (123.1°C–205.1°C) were directly obtained without post‐polymerization chain scission. Copolyesters with PTA/AA ratios of 5:5, 7:3, and 9:1 were processed on a pilot melt‐blowing line. The resulting nonwovens were characterized for fiber morphology, pore structure, tensile properties, wettability, air permeability, and baseline filtration performance. The results indicate that increasing the PTA content enhances chain rigidity and thermal stability while shifting the melt from viscous‐ to elastic‐dominated behavior. PBAT 7:3 achieved the optimal viscoelastic balance, yielding uniform fibers (22.31 μm) and cohesive web architecture, delivering favorable tensile strength (MD: 8.35 N), air permeability (3786 mm/s), and PM0.3 filtration efficiency (28.78% at 10 L/min). This work provides a practical synthesis‐tuning strategy for developing biodegradable melt‐blown nonwovens tailored for prefiltration, wipe, and sorbent applications.