Study On The Comppatity Of The Modified EP/CE Resin With The Liquid Oxigen And The Mechanical Properties

Future launch vehicles, such as reusable launch vehicles and expendable launchvehicles, need to minimize the gross lift-off weight for lower costs to orbit andincrease payload capabilities. One of the most crucial issues being considered isdurable,lightweight, cryogenic polymer composite propellant tanks.Liquid oxygen(LOX) has been one of the most important propel-lants nowadays, the preparation ofLOX polymer composite tank critical to the success of future launch vehicleprograms.Typically, most polymers and their composites are easily ignited in thepresence of oxygen, and are considered not suitable in the oxygen application.Therefore, the development of LOX compatible polymer matrix resins have to dealwith the compatibility of polymer matrix with LOX firstly.Epoxy resins, with many advantages, have been widely used in many cryogenicfields. Cyanate ester, another high performance matrix resin, can beself-polymerized to form a unique structure-triazine ring,which was reported to becompatible with LOX. For both cryogenic properties and LOX compatibility’s sake,epoxy resin and cyanate ester were co-cured in the study. LOX compatibility andtheir anti-oxidation properties of the co-cured compounds modified by antioxidantand benzoxazine specially were studied, LOX impact test was used to evaluatepolymer’s compatibility with LOX and thermogravimetic analysis was used toanalyze polymers’ oxidation. The resin systems which meet the requirements of theapplication in the cryogenic LOX tank will be achieved from the results of abovetests.The epoxy resin and cyanate ester resin was select as main matrix, andmodified by antioxidants and benzoxazine resin respectively. By studying theinfluence of different preparation processes on the performance of the curedresins,finally established the final preparation process. The condition of the heatchanging of the process of curing resins were analysed by the means of differentialscanning calorimetry, combined the glass transition temperature of the resin matrixresulting from the dynamic mechanical analysis, finally established the curingprocedure of the two modified resin systems.The cure behavior of benzoxazine withcyanate ester resin and epoxy resin was monitored by model reaction using nuclearmagnetic resonance(NMR) and infrared spectrum(IR).The thermostability and the antioxidation properties of the modified resins wasmeasured by the thermogravimetric analysis and the gain weight analysis underoxygen atmosphere.The obvious effects on improving the antioxidation properties has also been confirmed by the two means above.The results of the liquid oxygenimpact sensitivity tests were that the IRS of the resin systems E51/CE、E51/CE/k1010,E51/CE/BOZ(mole ratio of2:1:1and: two system) were respectively15.5%,5%,4%,2%.The contact angle of the modified resins was measured by Dynamic contactAngle analysis.And the tensile mechanical properties under the regular temprature and theliquid oxygen temperature was also measured.