Synthesis and characterization of ethylenediamine-modified F-44 phenolic epoxy fiber

F-44 phenolic epoxy fibers were produced through high-temperature dry spinning utilizing F-44 phenolic epoxy resin as the base material, combined with n-butanol and ethylenediamine (EDA) as the curing agent. The fibers were subsequently analyzed for their structural, thermal stability, microstructural, and mechanical properties using techniques such as Fourier transform infrared spectroscopy, micro-infrared imaging, thermogravimetric analysis, nuclear magnetic resonance, scanning electron microscopy, and fiber strength testing. The limitations of phenolic resins, including high brittleness, poor toughness, and low elongation at break, restrict their potential applications, necessitating modifications to broaden their utility. Research findings indicate that modifying EDA induces a ring-opening reaction of epoxy groups, thereby enhancing the resin’s structure and improving the thermal stability and mechanical properties of fibers. The thermal stability and mechanical strength of the fibers were optimized at an EDA concentration of 2.0 wt% and curing time of 30 min, resulting in a tensile strength of 105 MPa and an elongation at break of 27.6 %.