Facile Preparation of Hyperbranched Polysiloxane-Grafted Aramid Fibers with Simultaneously Improved UV Resistance, Surface Activity, and Thermal and Mechanical Properties

Simultaneously overcoming the poor UV resistance and surface inertness of aramid fibers while maintaining their excellent mechanical and thermal properties is a challenge. New grafted Kevlar fibers (HSi-g-KFs) were facilely prepared by in situ synthesizing hyperbranched polysiloxane with double bonds and epoxy groups on Kevlar fibers (KFs). As the molar ratio of water to silane was adjusted from 1.1 to 1.4, the surface morphology of HSi-g-KFs successively changed from unconnected dots to condensed dots and to a compact coating of hyperbranched polysiloxane. Compared with KFs, all HSi-g-KFs were found to have remarkably improved surface wettability and UV resistance. After 168 h of UV irradiation, the retentions of the modulus and break extension of the HSi-g-ICFs were as high as 95-97%. In addition, the HSi-g-KFs were found to have much higher thermal stabilities than KFs. These attractive results demonstrate that the method proposed herein is a new and facile approach for preparing high-performance aramid fibers for cutting-edge industries.