Study Of Liquid Oxygen Compatible Polymer Matrixes And Composites

Liquid oxygen (LOX) tank made of polymer composite is critical in the development of the launch vehicles of next generation, such as expendable launch vehicles (ELV) and reusable launch vehicles (RLV), to minimize the gross liftoff weight (GLOW). Based on the comprehensive review of the history of polymer composite LOX tank and the studies on LOX compatibility of the materials, this work focused on the LOX compatibility of the polymer materials, understanding the mechanism, establishing the evaluation methods and preparing the materials and the composites, which are the basic and most important issues involved in polymer composite LOX tank.Some phenomena and the consequences when polymer materials with poor compatibility used in LOX environment were discussed and explained, from which the mechanism and the evaluation means of LOX compatibility were established. Those are also the integrant guiding principles for selecting and modifying the polymers for better LOX compatibility. In this study, the LOX impact test was utilized as the main evaluation methods, accessorized by some new characterizations proposed.The physical and chemical factors of polymer materials on the LOX compatibility were studied systematically. It was found that the cavities on the sample surface reduce the LOX compatibility significantly and the heave on the surface may be favorable for the LOX compatibility. After LOX impregnating and pre-oxidation, polymer samples exhibited reduced LOX compatibility. The studies showed a good relationship between the anti-oxidation / flame-retardant properties of polymers and their LOX compatibility. Therefore, it can be concluded that the chemical principle of polymers'compatibility with LOX is oxidation, essentially the same as oxidation and combustion in ambient conditions. These conclusions are very important for LOX compatible polymers'preparation and applications.The process and the mechanism of the LOX impact sensitivity test were studied based on the direct observations. When impacted,"hot spots"on the surface of polymers appeared at first. The high temperature on"hot spots"made polymers oxidized and gaseous organic species were released and mixed with oxygen. The sample was then ignited, resulted in either...