Preparation and application of superhydrophobic polypropylene melt-blown nonwovens by organic solvent etch

Since the global outbreak of COVID-19, medical masks have become one of the most concerned pieces of epidemiological protection equipment. Polypropylene melt-blown nonwovens are the core filtration materials of medical masks, but the filtration performance deteriorates drastically with prolonged use and water vapor adherence. Here, a series of organic solvents were used to etch the melt-blown nonwovens to construct a graded rough structure and thus obtain durable superhydrophobic melt-blown nonwovens. The melt-blown nonwovens etched with a mixture of cyclohexane and n-hexane (volume ratio: 3:2) at 65 °C for 30 min exhibited excellent superhydrophobicity (water contact angle ∼153.5°, sliding angle ∼5.9°), high durability and great chemical resistance. The mechanical strength of the superhydrophobic melt-blown nonwoven has changed very little compared to the original melt- blown nonwoven, and it has a good filtration efficiency (89.2 %) and low wind resistance (24.3 Pa). In addition, the superhydrophobic melt-blown nonwoven can achieve more than 8.5 times its previous mass of organic solvent adsorption, with oil and water separation efficiency reaching over 91 %. Therefore, the PP melt-blowns prepared by the organic solvent etching method have greatly improved mask filtration performance and they also have great application prospect in oil-water separation.