Abstract
A series of organopolysilazane (OPSZ) composite coatings were synthesized via a grafting reaction between OPSZ and epoxy resin, which were applied to protect the surfaces of combustible cartridge cases. The chemical compositions were characterized by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results of heat-resistance tests indicated that the optimum OPSZ composite coating could prevent combustible cartridge cases from burning for 175.56 s at 250°C. The glass transition temperatures (Tg) of the OPSZ composite coatings were dependent on the polymer structure and were in the range of 254.7–454.0°C. All of the coatings showed good thermal stability, with temperatures at which 50% weight loss occurred being greater than 600°C. The results indicated that the OPSZ composite coatings could effectively improve the heat resistance of combustible cartridge cases. Based on scanning electron microscopy images after salt water exposure tests and the water contact angle, the OPSZ composite coating could effectively improve the environmental adaptability of combustible cartridge cases. This study demonstrated that the ceramic precursor OPSZ, as a protective material, provides a novel way to fabricate various coatings to protect combustible cartridge cases from high temperatures, environmental humidity, and corrosive air.