Preparation And Properties Of Low Dielectric Polyimide Nanocomposites

In the context of the rapid promotion of the concept of the Internet of things and the rapid promotion of Internet technology to more and more electronic devices,new high-bandwidth network technologies have been introduced one after another.As an important substrate for electronic packaging and energy storage,dielectric polymer composites have been systematically studied and widely used.According to requirements,electronic packaging materials need to have a low dielectric constant and a low dissipation factor,but the dielectric constant of almost all original PIs is greater than 3,which cannot meet the growing needs of microelectronics and 5G technology.Therefore,there is an urgent need to further reduce the dielectric constant of the PI film.(1)Three different types of pure polyimide films were prepared by a two-step method.The test results show that the properties of the three films are significantly different due to the difference in structure.The thermal stability,optical and mechanical properties of BPDA-TFMB PI polyimide film are the best compared to PMDA-TFMB PI polyimide and BTDA-TFMB PI polyimide.However,the dielectric properties of BPDA-TFMB PI polyimide film are relatively poor compared to PMDATFMB PI polyimide and BTDA-TFMB PI polyimide.Although the dielectric constant and dielectric loss of BPDA-TFMB PI polyimide film are better than those of BTDA-TFMB PI polyimide,However,it is inferior to PMDA-TFMB PI polyimide,which also provides a larger space for subsequent lowdielectric modification.Therefore,the BPDA-TFMB PI polyimide film was selected as the substrate for the subsequent preparation of low-dielectric polyimide and its composite film materials.(2)The Fe-MIL-88/Polyimide composite film with low dielectric constant was prepared by a combination of hydrothermal method and solution blending method.Firstly,Fe-MIL-88 nanoparticles with abundant pores are synthesized by hydrothermal method.Then use the solution blending method to dope the synthesized Fe-MIL-88 nanoparticles into the BPDA-TFMB type polyamic acid solution,The Fe-MIL-88 nanoparticle/polyimide composite film with different content was prepared by thermal imidization method,and Fe-MIL-88 nanoparticle/polyimide was analyzed by various characterization methods such as FT-IR,XRD,SEM,etc.Thermal analysis equipment,tensile tester and impedance analysis equipment are used to analyze the thermal stability,mechanical properties and dielectric properties of the composite film.By adding different content of Fe-MIL-88 nanoparticles,the dielectric constant of the composite film is reduced to the lowest 2.91.Effectively improve the dielectric properties of the polyimide film.(3)The hollow silica/polyimide composite film with low dielectric constant was prepared by a combination of hydrothermal method and sol-gel method.First,formaldehyde and resorcinol are used to prepare phenolic resin balls as a sacrificial template,and a layer of silica is wrapped on the phenolic resin balls by sol-gel.Under calcination conditions,the phenolic resin template is removed to obtain hollow silica.The obtained hollow silica spheres are uniform in size and no agglomeration occurs.Then the synthesized hollow silica spheres are doped into the pure polyimide film by the solution blending method.By changing the content of silica spheres,we studied the effect of the content of hollow silica spheres on the properties of the film.And through various characterization methods such as FT-IR,XRD,SEM,etc.,the microstructure,degree of polymerization and degree of order of the six poly hollow silica spheres/polyimide composite films were analyzed.Thermal analysis instruments,tensile testers and impedance analysis instruments are used to analyze the thermal stability,mechanical properties and dielectric properties of the composite film.By adding different amounts of silica nanoparticles,the dielectric constant of the composite film is reduced to2.65 as low as possible.Effectively improve the dielectric properties of the polyimide film.