Structural and Performance Effects of Self-Assembled Composite Antibacterial Additives on PP Melt-Blown Nonwovens Based on Melt Reaction Extrusion

In this study, a hybrid microsphere structure with a polyhexamethyleneguanidine hydrochloride (PHMG) core and a nano-zinc oxide (Nano-ZnO) antibacterial additive shell was designed through the reaction extrusion in polypropylene (PP). The realization of this structure enabled the successful resolution of the agglomeration problem of Nano-ZnO and achieved a synergistic antibacterial effect between Nano-ZnO and PHMG. Special attention was paid to the interaction between Nano-ZnO and PHMG through the organic–inorganic hybridization. In addition, the nonwoven materials with different Nano-ZnO and PHMG contents were prepared via a melt-blown technique in PP, and their antibacterial properties were evaluated as well. Based on the findings, the synergistic antimicrobial mechanism of Nano-ZnO/PHMG structures was established. The results showed that the addition of 2% Nano-ZnO and 1% PHMG in PP (PP/2%ZnO/1%PHMG) allowed for the production of a melt-blown nonwoven material with an antibacterial efficiency of 99.99% against Staphylococcus aureus and Escherichia coli . Besides that, the material exhibited the outstanding performance and durability (the breaking strength of 2.43 N, the air permeability of 537 mm/s, the filtration efficiency of 97.25%, and the filtration resistance of 28.38 Pa).