Fabricating Aramid Fibers with Ultrahigh Tensile and Compressive Strength

Abstract

High tensile and compressive strengths are essential for fiber-reinforced plastic utilized in complex loading conditions. However, it is challenging to produce aramid fibers with both high tensile and compressive strengths. In the present work, graphene oxide modified with p-phenylenediamine (GO-PPDA) was introduced to simultaneously increase the tensile strength (up to 6.75 GPa) and compressive strength (up to 676.8 MPa) of the heterocyclic aramid fibers. GO-PPDA covalently links polymer molecular chains via amine groups, inducing a regular alignment that enhances crystallinity and orientation. Multi-scale characterization indicates that the two-dimensional graphene oxide (GO) enhances interfacial interactions among molecular chains, nanofibers, and fibril bundles, resulting in reduced sheath-core structural disparity and increased fiber densification. Atomistic simulations demonstrate that the enhancements in orientation, densification, and interfacial interactions of the building blocks contribute to the simultaneous improvement in both the tensile and compressive strengths of composite fibers. Finally, we demonstrate that the exceptional mechanical properties of these fibers can be effectively transferred to their composite materials, which is crucial for practical applications.

Graphical Abstract

The novel heterocyclic aramid fibers containing GO were prepared via in-situ polymerization and wet spinning. GO-PPDA-2/AF exhibits an ultra-high tensile strength of 6.75 GPa and compressive strength of 676.8 MPa, with high-performance tows produced in batches. These exceptional mechanical properties can be effectively transferred to composite materials.