Preparation and Properties of Molybdenum‐modified High‐ortho Thermosetting Phenolic Fiber

Abstract

The study aims to produce thermosetting resin from synthesized molybdenum‐modified high‐ortho thermoplastic phenolic resin through an addition reaction. Then, molybdenum‐modified high‐ortho thermosetting phenolic resin is blended with polyvinyl butyral and undergoes wet spinning to prepare as‐spun fibers and obtain high‐ortho molybdenum phenolic fibers via solution curing, microwave curing, or heat curing. Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, scanning electron microscopy, and fiber strength testing were used to investigate the structure and properties of molybdenum‐modified high‐ortho phenolic fibers. Results showed that adding molybdic acid introduced Mo−O bonds into the molecular chain of high‐ortho phenolic resin, thereby improving the degree of cross‐linking and thermal stability. The residual carbon content of the fibers after heat treatment exceeded 60%, and the elongation at break and the breaking strength of the microwave‐cured fibers reached 4.2% and 155 MPa, respectively, and the mechanical properties were relatively good. The study of high‐ortho phenolic fibers aims to improve their properties and expand their applications through resin modifications. It provides a possible fiber preparation strategy for improving heat‐resistant phenolic fibers, thereby guiding the research of modified high‐ortho phenolic fibers.