Functionalized Graphene/Polyimide Nanocomposites under Different Thermal Imidization Temperatures

Abstract

4-Amino-N-hexadecylbenzamide-graphene sheets (AHB-GSs), used in the preparation of the polyimide (PI) nanocomposite films, were synthesized by mixing a dispersion of graphite oxide with a solution of the ammonium salt of AHB. The atomic force microscope image of functionalized-GS on mica and a profile plot revealed the average thickness of AHB-GS to be ~3.21 nm. PI films were synthesized by reacting 4,4'-biphthalic anhydride and bis(4-aminophenyl) sulfide. PI nanocomposite films containing various contents of AHB-GS over the range of 0-10 wt% were synthesized using the solution intercalation method. The PI nanocomposite films under different thermal imidization temperatures, 250 and 350 o C, were examined. The graphenes, for the most part, were well dispersed in the polymer matrix despite some agglomeration. However, micrometer-scale particles were not detected. The average thickness of the particles was <10 nm, as revealed from the transmission electron microscope images. Only a small amount of AHB-GS was required to improve the gas barrier, and electrical conductivity. In contrast, the glass transition and initial decomposition temperatures of the PI hybrid films continued to decrease with increasing content of AHB-GS up to 10 wt%. In general, the properties of the PI hybrid films heat treated at 350 o C were better than those of films heat treated at 250 o C.

Flexible free-standing composite films having 3D continuous structures of hollow graphene ellipsoids

“…In the present experiment, PVA was used as a matrix owing to its good processability to form free-standing film, originating from its outstanding dispersibility in aqueous solution, flexibility, adhesion and oxygen barrier property. [31][32][33][34][35][36][37][38][39][40][41][42][43] As a result, PVA dispersed in solution was well infiltrated into the 3D hollow graphene structure via a dip-coating process, and free-standing graphene/PVA films of ca. 4.3 µm thickness were fabricated after drying at 70 °C.…”

Preparation and Characterization of Polyimide/Alumina Composite Films as Improved Solid Dielectrics

“…[1][2][3] Large demand for the solid thin-film dielectrics with high dielectric constants especially for use in the fabrication of high end capacitors has been stated in the literatures. [4][5][6] Among various organic polymers, the polyimide (PI) has been paid a lot of attention due to excellent dielectric properties, attractive mechanical properties, and outstanding thermal stability, which have been extensively applied in terms of the dielectric and microelectronic industry. 1 However, it is proved that neat PI cannot still meet the ever-growing demand of electrical insulation systems.…”