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Abstract
Industrialization and urban growth have increased particulate matter (PM) levels in the air, which threatens human health and ecosystems. To encounter the problem with air pollution, the use of lightweight and 3D melt-blown nonwovens has got immense research attention. Its ultra-fine fibers can form dense, intricate webs that efficiently trap the smallest airborne particles. Furthermore, this structure can maintain breathability because of its high porosity. Polypropylene (PP) is the most utilized for melt blowing systems due to its low cost, ease of processing, hydrophobic nature, chemical inertness, and favorable filtration properties. However, sustainability concerns are driving interest in eco-friendly, bio-based alternatives which offer both durable performance and biodegradability at their end-of-life. The present study aimed to develop bio-based, biodegradable blended melt-blown nonwovens (lab scale) from polylactic acid (PLA), polyhydroxyalkanoate (PHA), and polybutylene succinate (PBS) with acceptable PM0.3 filtration. The processability and effects of processing parameters, such as air pressure, melt temperature, and blend ratio on structures and performances (fiber diameter, physical, thermal, barrier and mechanical performance) of the developed melt-blown webs were investigated. Negative corona charging was used to impart a persistent electrostatic charge to the fibers, transforming them into electrets. The charge significantly enhanced the filtration performance of the developed webs by capturing PM0.3 aerosol particles through electrostatic attraction in addition to mechanical filtration. Furthermore, the presence of charge additives (1 wt.% BaTiO3) in the webs during corona charging enhanced the materials ability to store electrostatic charge. The study demonstrated that reducing distance improved filtration efficiency of corona charged webs. And optimal filtration efficiency for PLA webs was achieved at an applied voltage of -30 kV or higher. Increasing the electrodes-samples distance consistently reduced efficiency, especially at -10 kV. Knowledge gathered from the lab scale processing was used for pilot-plant production of PLA and PLA/PHA blended webs with >95% filtration efficiency and investigate their structure-properties relationship. Findings of this study will create a new dimension for developing next generation filter media for PM0.3 while maintaining low pressure drop and durability in real-world conditions.