Atomic Oxygen Erosion Effect Analysis And Protective Research On Polymer Materials

Atomic oxygen （AO） is the predominant and the most active component of low earthorbit （LEO） atmosphere. Polymer materials may fail to function due to the AO erosion,thus endangering aerospace machine life. From the perspective of material analysis, wesystematic studied the atomic oxygen erosion effect of polymethyl methacrylate （PMMA）and silicon rubber. To retard the AO erosion effectively, we tried to prepare SiO^xfilms onthe surface of polymethyl methacrylate （PMMA） and silicon rubber by solvothermalmethod and plasma polymerization, respectively. The preparation conditions anddefending effect of films were studied. Main results were as follows:（1） The atomic oxygen erosion effect of PMMA was analyzed. The mass loss, surfacemorphology and structure, transmittance of PMMA before and after AO exposurewere investigated. The results indicated that PMMA was eroded seriously after AOexposure to a fluency of3.3×10²⁰atoms/cm². The surface morphology andstructure of pristine PMMA obviously changed and optical transmittance markedlydecreased.（2） The atomic oxygen erosion effect of silicon rubber was analyzed. The surfacemorphology and structure, transmittance of three different silicon rubbers wereinvestigated. The total mass loss of silicon rubbers in vacuum was measured. Theresults indicated that the interaction between AO and silicon rubbers led to thedecrease of optical transmittance. Irregular cracks appeared on the surface andsurface materials peeled off.（3） Using solvothermal method to modify the surface of polymethyl methacrylate（PMMA）, the silica films were prepared on it via sol solution and solvothermaltreatment. The interfacial effect between film and PMMA substrate in thesolvothermal process was studied. The samples were irradiated by atomic oxygen（AO） in a ground-based simulation system, and the surface morphology andstructure of films were investigated. The results indicated that solvothermal process is an effective method to improve the adhesion between the silica film andsubstrate. After AO exposure, the inorganic silica components increased due to theoxidation of organic silicon substances.The silica films become more compact,without peeling off, and has good optical transparency.（4） Gradient thin films were deposited on the surface of silicone rubber by plasmapolymerization. The surface morphology and structure of films before and afterAO irradiation were studied. The results indicated that gradient deposition couldimprove the adhesion between film and substrate. The plasma polymerized coatingwas uniform and smooth. The transmittance and AO resistance of substrate wereimproved.