Fabrication of polyimide/graphene nanosheet composite fibers microwave-assisted imidization strategy.

Here, a rapid and efficient strategy was introduced to prepare polyimide/graphene nanosheet (PI/GN) composite fibers by microwave-assisted imidization. The mechanical properties of the PI/GNs (1 wt%) fibers treated by microwave-assisted imidization were apparently improved with the tensile strength of 1.12 GPa at 350 °C, which was approximately 1.

Consecutive large-scale fabrication of surface-silvered polyimide fibers via an integrated direct ion-exchange self-metallization strategy.

Herein, we report our success on the large-scale online preparation of surface-silver-metallized polyimide (PI) fibers by utilizing silver ammonia complex cation ([Ag(NH3)2](+)) as the silver (Ag) precursor and pyromellitic dianhydride/4,4'-oxidianiline (PMDA/4,4'-ODA)-based polyimide as the matrix via a direct ion-exchange self-metallization process integrated within a consecutive fiber-spinning procedure. The method works by using the online freshly prepared PMDA/4,4'-ODA-based poly(amic acid) (PAA) fibers as the starting material to perform an ion-exchange reaction in aqueous silver(I) solution to load silver(I) into the PAA precursor fibers, followed by a programmed stepwise thermal treatment process to convert PAA to its final imide form with the concomitant silver(I) reduction and the subsequent aggregation, producing the surface-silvered polyimide hybrid fibers. The influence of thermal cycles on the formation of silver nanostructures, and the variation of surface morphologies and fiber properties during the heating process were investigated.

Incorporation of silver nanoparticles into the bulk of the electrospun ultrafine polyimide nanofibers via a direct ion exchange self-metallization process.

This paper reports our works on the preparation of the silver-nanoparticle-incorporated ultrafine polyimide (PI) ultrafine fibers via a direct ion exchange self-metallization technique using silver ammonia complex cation ([Ag(NH(3))(2)](+)) as the silver precursor and pyromellitic dianhydride (PMDA)/4,4'-oxidianiline (4,4'-ODA) polyimide as the matrix. The polyimide precursor, poly(amic acid) (PAA), was synthesized and then electrospun into ultrafine fibers. By thermally treating the silver(I)-doped PAA ultrafine fibers, where the silver(I) ions were loaded through the ion exchange reactions of the carboxylic acid groups of the PAA macromolecules with the [Ag(NH(3))(2)](+) cations in an aqueous solution, ultrafine polyimide fibers embedded with silver nanoparticles with diameters less than 20 nm were successfully fabricated.