No abstract

In contrast to the commonly used nondegradable melt-blown nonwovens, polylactic acid (PLA) melt-blown nonwovens are renewable and biodegradable, making them very environmentally friendly at their end of life. However, the strength and toughness of PLA melt-blown nonwovens are generally insufficient for practical applications. Herein, we report a straightforward and universal strategy for fabricating PLA melt-blown nonwovens with superior mechanical properties. In this process, hierarchical controlling of the high-temperature and high-speed airflow considerably increases the polymeric chain orientation and crystallization of PLA. High-molecular-weight (Mw) PLA polymeric chains can be entangled to reduce the negative effect of excessive polymeric chain orientation on elongation, resulting in a gain in strength and toughness at the same time. The resulting PLA melt-blown nonwovens exhibit enhanced strength (1.8 MPa, up by 157%), higher elongation (35.6%, up by 256%), and excellent toughness (0.59 MJ/m3, up by 788%). Additionally, a plausible tensile failure mechanism for melt-blown nonwovens is proposed based on the tensile fracture process. Strikingly, the PLA melt-blown nonwovens exhibit high particulate matter (PM0.3), removal efficiency (92.6%), and low pressure drop (12.3 Pa). The successful preparation of PLA melt-blown nonwovens with superior mechanical properties will satiate the growing demand for sustainability, personal protection, and environmental protection.