Robust aramid nanopaper based on the uniform wrap of sodium alginate on the surface of nanofibers

Compared to the individual fiber, the core problem limiting the mechanical strength of the aramid nanopaper is the weak interfacial bonding strength, and the hydrogen bond-induced aggregation is an important factor influencing the well compositing of aramid nanofibers (ANFs) with other enhancers. In this work, we introduced sodium alginate (SA) as a mechanical additive during the formation process of ANFs to realize the uniform wrapping of the SA on the surface of ANFs. The resultant ANFs/SA paper shows an ultimate strength of 308.23 MPa, a toughness of 42.33 MJ⋅m−3, and an elongation of 21.99%, which are 1.63, 5.16, and 3.12 times of the pure ANFs film. The excellent mechanical performances are attributed to the good dispersion of SA in the ANFs matrix, which can result in the fine physical cross-link and enhanced hydrogen bonding at interfaces. Meanwhile, the ANFs/SA composite also shows favorable electrical insulation behaviors.Graphical abstract