Crystallization and Mechanical Properties of the Polylactide Melt Blown Nonwovens

Polylactide (PLA), a promising biodegradable semi-crystalline polymer, has not been widely used in melt blown nonwoven field due to its poor mechanical property, which is related to the crystallization behavior of the polymer. This article aims to investigate the relationship between the crystallization and the mechanical property of the PLA melt blown nonwovens. PLA melt blown nonwovens were prepared under different airflow conditions. The microstructure, crystallization, and mechanical property were studied using SEM, DSC, XRD, tensile testing, and numerical simulation method. The results show that an increase of interfiber junctions or crystallinity is conducive to the improvement of the mechanical property of the PLA melt blown nonwovens. Optimizing the airflow conditions has a positive effect on the crystallization and mechanical property; however, the PLA melt blown nonwovens are still in an amorphous state with small grain size. Annealing treatment favors the formation of the ordered alpha crystals and less disordered alpha' crystals. Moreover, the lager grain size and crystallinity after annealing at 90 degrees C for 30 min can further increase the mechanical strength (up to 1.5 times) of PLA melt blown nonwovens.