Structure Stability, Flame Retardancy, and Antimicrobial Properties of Polyurethane Composite Nanofibers Containing Tannic Acid and Boron-Doped Carbon Nanotubes

Abstract

A polyurethane (PU) composite nanofiber with superior flame retardancy and antimicrobial property is developed through the simultaneous incorporation of boron-doped carbon nanotubes (CNTs) and tannic acid (TA), resulting in excellent thermal, mechanical, and eco-friendly flame-retardant properties. The tensile strength and peak heat-release rate of the composite nanofiber increase with increasing filler content, with the optimal performance (7.38 +/- 1.04 MPa and 254 W g(-1)) being achieved at 3 wt% filler. Using a series of analytical techniques, it is demonstrated that the nanostructure of the neat PU completely collapses upon heating, transforming into a film-like structure; in contrast, a higher loading of nanofiller leads to a higher heat-shielding capability, thereby facilitating preservation of the composite nanofiber structure. Finally, the antibacterial activity is shown to increase as a result of the synergic effect of the boron-doped CNTs and TA.