Preparation And Properties Of Functional Polyimide Composite Films

With the rapid development of science and technology,the use of various wireless communication devices and high-frequency and high-power electronic components has become more and more extensive.While providing high efficiency and convenience for human society,the electromagnetic radiation generated by them has become increasingly evident,which has brought about a series of problems affecting human production and life,and has become a new source of pollution threatening human health.Therefore,effective electromagnetic shielding materials are developed to reduce the damage of various electromagnetic waves to the environment and human beings.Polyimide(PI)is widely used in many high-tech fields and daily life because of its excellent performance,such as microelectronics,aerospace devices,highly integrated electronic circuits and so on.As a common packaging material of integrated electronic circuits,it also has certain requirements in electromagnetic shielding.Therefore,it is particularly important to study the modification of polyimide to improve its electromagnetic shielding ability.Tourmaline is a natural borosilicate with complex structure.Tourmaline belongs to tripartite system.It mainly consists of silicon-oxygen tetrahedral ring crystal.Because of its special crystal structure,tourmaline has permanent charged characteristics and can form electric field permanently.Because of its own electric field and polyimide composite,it has a certain static shielding function,because the introduction of inorganic materials to a certain extent enhance its thermodynamic properties.Based on this,this paper,polyimide/tourmaline composites were prepared,and the second composite film was prepared by silver modification of tourmaline.The structure and composition of the composite films were characterized by means of scanning electron microscopy,infrared spectroscopy and X-ray diffraction.The properties of the films were analyzed by thermogravimetric analyzer,mechanical testing machine and network analyzer,further understanding the Principle of Functional Change of Thin Films.Firstly,tourmaline was modified by conventional silane coupling agent(APTES),the surface of tourmaline was modified with-NH₂,then 6FDA-ODA-BPADA copolyimide with anhydride-terminated was synthesized.Through chemical bond reaction,tourmaline was modified on the molecular chain of polyimide,and then the composite film was prepared by tape casting.XRD and SEM images show that tourmaline has been successfully introduced into the film,and the content distribution of tourmaline in different proportions is different,but when the proportion increases to a certain extent,some micro-agglomeration occurs.TGA curves show that the thermal decomposition temperature of composite films increases at the beginning and then decreases,and they are still better than those of uncompleted tourmaline films.When the tourmaline content is 5 wt%,the thermal performance peaks,5%thermal weightlessness temperature reaches 513?,which is nearly 15?higher than that of pure film;the electromagnetic shielding energy efficiency of this addition also reaches the optimal value in a series of gradients;the mechanical curve shows that the tensile strength of composite film is obviously optimized,the Young's modulus is increased,and the elongation at break is reducedIn order to further enhance the shielding energy efficiency of thin films,Then tourmaline was modified with silver nanoparticles.The surface of tourmaline was successfully modified by silver nanoparticles through XRD and SEM spectra,The distribution of Ag particles and the amount of modification can also be observed.The composite films were prepared by the same method.The TGA and mechanical curves showed that the introduction of silver nanoparticles affect the thermodynamic properties of the films.The electromagnetic shielding show that the introduction of silver nanoparticles improves the electromagnetic shielding effectiveness to some extent compared with the former film,explained that the addition of Ag particles promotes the improvement of energy efficiency...