Enhancing thermo-oxidative stability of thermoset polyimide composites using nano neodymium oxide particles

Thermoset polyimide was modified with nano neodymium oxide to improve its thermo-oxidative stability. The modified polyimide prepreg was prepared by a hot-melt process, and its composite laminates were successfully fabricated by hot-press molding. Moreover, the effects of nano neodymium oxide content on the thermo-oxidative stability and the mechanical properties of modified thermoset polyimide composites, as well as its modification mechanisms, were investigated. The results indicated that the modified composites with nano neodymium oxide exhibited dramatically higher thermal oxidation stability and flexural strength. The composites achieved optimal comprehensive performance, particularly when the nano neodymium oxide addition content was relatively low (1 wt%). Furthermore, compared with the unmodified composites under the same isothermal aging conditions at 350 °C for 200 h, the weight loss rates of the modified polyimide composites notably decreased by 25%, and the flexural strength properties significantly improved by 46%. In addition, the causes of the varied mechanical properties of the modified polyimide composites were assessed by microstructural characterization and Fourier transform infrared spectra.