Processing, structure, and properties of PLA/PHA blended melt-blown nonwoven webs for filter media applications

Melt-blown nonwovens used in respiratory protection are predominately made from non-biodegradable polypropylene (PP), raising sustainability concerns. This study developed bio-based, biodegradable melt-blown nonwovens using polylactic acid (PLA) and polyhydroxyalkanoate (PHA) blends for efficient PM0.3 filtration. The effects of key processing parameters (air pressure, melt temperature, and blend ratio) on fiber morphology, thermal behavior, filtration, and mechanical properties were evaluated. The fiber diameters of developed webs ranged from 3 to 7 µm, and the incorporation of PHA significantly increased fiber diameters. The glass transition temperature decreased from 62.9 °C (pure PLA) to 58.3 °C (90/10-PLA/PHA), while melting temperature showed a slight reduction, indicating minor changes in crystallinity. The developed webs achieved > 96% PM0.3 removal efficiency and < 51 Pa pressure drop after corona charging (− 50 kV). Furthermore, PLA/PHA blended webs also showed improved mechanical performance, with ~ 14.1% higher maximum force and ~ 27.6% greater strain at maximum load. These results demonstrate that PLA/PHA melt-blown nonwovens are promising biodegradable alternatives to PP-based filter media.