The Ad‐Micellar Preparation of Para‐Aramid Nanofiber/Polyacrylate Nanocomposite

The 1D nanofibers of high‐performance para‐aramid provide a new kind of promising reinforcement fillers for polymer‐based nanocomposites, but great challenges are presented in their homogeneous dispersing and reliable interface building within the viscous polymer matrix. In this work, polymerizable surfactant‐based ad‐micellar polymerization is proposed to immobilize the radical grafting polymerization of polyacrylate at the surfaces of para‐aramid nanofibers (PANF) prepared by polymerization‐induced self‐assembly and pre‐decorated by methacryloxy (MA) groups. Via this method, a PANF/polyacrylate (PA) nanocomposite latex was in situ prepared, which was homogeneously dispersed in water, similar to traditional polymer latexes. In comparison to the direct blending, the compatibility of the nanofibers with polyacrylate was much improved due to the grafting of polyacrylate on nanofiber surfaces. Following assisted by the vacuum‐assisted filtration (VAF) to optimize the in‐plane orientation, nanocomposite films containing a high nanofiber content (66.1%) showed excellent tensile strength (35.8 MPa) and modulus (2.71 GPa). Especially, the modulus increased by orders of magnitude compared to that of the weak, unfilled PA latex film. Furthermore, the method demonstrates advantages including a low‐viscosity latex form, high tolerance to monomer types and nanofiber contents, and environmental friendliness, providing a promising preparation strategy for nanocomposites based on para‐aramid nanofibers and emulsion polymers.