Facile Interface Design Strategy for Improving the Uvioresistant and Self-Healing Properties of Poly(p‑phenylene benzobisoxazole) Fibers

Graphene-based coaxial hybrid fibers (CHFs) with a typical core–sheath structure have attracted extensive attention in recent years because of their potentially excellent mechanical performance. However, direct introduction of the micrometer-thick graphene stack structure on the extremely inert fiber surface with little negative effect has barely been reported so far and is still a great challenge. In the present work, a facile and cost-efficient dimensionally confined hydrothermal reduction, static adsorption, and thermal-assisted shrinkage sequential treatment strategy was developed to fabricate one-dimensional CHFs. The large-scale reduced graphene oxide–metal organic framework (RGO–UIO-66) hybrid layer and poly­(p-phenylene benzobisoxazole) (PBO) fiber serve as the sheath part and core part, respectively, and the final product is denoted as PGU–CHFs. The experimental results confirmed that the prepared monofilament composite with thermoplastic polyurethane (PGU–CHF–TPU) exhibited an excellent and stable intrinsically self-healing efficiency (about 85%) over 5 cycles and an extraordinary uvioresistant performance (increased by 128%) compared to those of pristine PBO fibers after 288 h UV aging irradiation. Moreover, the anti-ultraviolet (UV) properties of PGU–CHFs at 96 h are basically at the optimum level among most of the reported literatures at present after comparison. The highly near-infrared photothermal conversion ability and stability of micrometer-thick RGO stack structure and the synergism of RGO–UIO-66 hybrid sheath layer including UV adsorption, shielding attenuation, and reflection are responsible for the satisfactorily interfacial self-healing efficiency and UV-resistance properties of PGU–CHFs, respectively. Considering the diversities and versatilities of RGO and MOFs, the proposed fabrication strategy will promisingly endow PBO fibers with great application potential in the other fields such as fiber-based sensors and smart fibers.