Preparation and properties of the polyimide thin films reinforced by acylchloride-functionalized multiple-walled carbon nanotubes

A series of polyimide composites with various mass fractions of multi-walled carbon nanotubes (MWNTs) were prepared by in situ polymerization. To increase the chemical compatibility of carbon nanotubes with the polyimide matrix, MWNTs were treated with an acid mixture and sulfoxide chloride in turn. The modified MWNTs are dispersed homogeneously in the matrix while the structure of the PI and MWNTs are stable in the preparation process. The composite films hold preferable thermal stability the same as the pure PI. The composite films exhibited good thermomechanical properties. The storage modulus increased significantly by increasing MWNT content and decreasing the enhancement of temperature. The films’ glass transition temperature increased with enhancing of MWNTs frictions. The dielectric constants of the composites decrease with increasing frequency and increase sharply with the adding of MWNTs, which is favorable for practical use in anti-static materials and embedded capacitors.