Nano aluminum nitride fillers for enhanced mechanical and thermal properties of GFRP in cryogenic temperature settings

Glass fiber-reinforced polymer (GFRP) composites, with epoxy resin or a blend of cyanate and epoxy resins as the matrix, have been used as insulating materials of high-field, large-scale superconducting magnets for accelerators and magnetic confinement fusion. However, the GFRP does not fully meet the requirements for the next generation of magnetic confinement fusion with respect to the mechanical and thermal performance at cryogenic temperature and huge electromagnetic stress. This paper introduces a method for enhancing both the mechanical and thermal properties of the GFRP composites using aluminum nitride (AlN) nanoparticles. The fabrication of the AlN-GFRP composite involved a method that combines “dip absorption” with vacuum-assisted resin transfer molding (VARTM). The dip absorption method was utilized to deposit AlN nanopowders onto glass fibers, resulting in the preparation of AlN-glass fiber layers. Subsequently, the AlN-woven glass fibers were incorporated to reinforce the cyanate ester/epoxy based composites using the VARTM technology. The mechanical and thermal properties of the AlN-GFRP composites were assessed across varying temperatures. The results indicate that the short-beam shear strength (SBS strength) of the AlN-GFRP composites improves at cryogenic temperatures compared to that of the GFRP composites without AlN. Additionally, enhanced thermal conductivities are observed across different temperature ranges for the AlN-GFRP composites. The coefficient of thermal expansion between 77 K and 300 K of the composites significantly decreases with the addition of the AlN nanopowders.