Preparation And Electron Radiation Resistance Property Of Functional Polyimide Film

Spacecraft is one of the most important carriers in the outer spaceexploration.In recent years,with the rapid development of spaceexploration technology,flexible polymer materials are widely used in new spacecraftsto deal with the threat of the complex space environment.Asa kind offlexible polymer materials,polyimide(PI)film is widely used in spacecrafts due toitsexcellent mechanical properties,goodthermal performance,electrical properties,chemical stability and radiation-resistant performance.However,the performancesof traditional PI film are significantlydecreasedunder complex radiation environment.Therefore,as a breakthrough point of the solution to the above problem,the radition hardness of PI materials has received growing scientific attentions.In this work,a new method known as atomic layer deposition(ALD),was developed to prepare inorganic oxides incroported flexible polymer materials.As a novel thin-film preparation technology,ALD has attracted scientific attentions due to its outstanding advantages,such asthe controllable coating thickness and uniform coatingdensity,which endow ALD technologywith wideapplications in microelectronics,aerospace,catalysts,optics and other fields.Based on ALD technology,a series of PI composite filmswere prepared by coating Al₂O₃or TiO₂ on the upper and bottomsurfaces of pure PI films,respectively.The inorganic oxide enchance the electron radition hardness of the PI films because of its protective effect.The research contents are as follows:1.The preparation and properties of pure PI films.Pyromellitic anhydrideand3,3',4,4'-biphenyl tetracarboxylic diandhydridewere polymerized with differentdianhydride monomers to prepare eight kinds of pure PI films.Then,two kinds of pure PI films with excellent mechanical properties wereselected to carry out electron radiation tests.The structuresand properties of two above pure PI films were characterized by FTIR,SEM,XPS,TGA and tensile tests.2.The preparation and properties of PI/Al₂O₃ composite films..Based on ALD technology,PI/Al₂O₃ composite filmswere prepared by coating Al₂O₃ on the upper and bottomsurfaces of the two above pure PI films,respectively.The structures and properties of PI/Al₂O₃ composite films were characterized.3.The preparation and properties of PI/TiO₂ composite films.Based on ALD technology,PI/TiO₂ composite filmswere prepared bycoating TiO₂ on the upper and bottomsurfaces of the two abovepure PI films,respectively.Thestructures and properties were characterized and compared with PI/Al₂O₃ composite films.The experimental results indicatethat after electron radition,the mechanical properties and thermal performance of the pure PI films were obviously decreased.Compared with the pure PI films,the properties of the PI composite films wereclearly improved.The tensile strength of PI/Al₂O₃composite filmswasslighly decreased,while the thermal performance of PI/TiO₂composite films rarely changed.