Study On BTDA-ODA Polyimide Nanofiber Prepared By Electrospinning

Electrospinning, a unique characteristic of easy operation, is one of best methods to make nanofibers. Electrospun membranes are able to form a large surface-to-volume ratio, highly porous mesh, highly length-diameter ratio and uniform fiber improves performance for many potential applications. For example, fabrics are suited to sorbing material and filtering material, because of their super adsorption, excellence filter capacity and good heat preservation, fabrics also be developed to fibers which have many functions such as antisepsis, radiation resistance, flame retardance and shielding. Aromatic polyimides, as a high performance functional fibers material, have marked excellent physical and chemical properties like thermal stability, dielectric property, radio resistant property, fire resistance, high strength, high modulus and nonpoisonous. The polyimide(PI) nanofiber was prepared by electrospinning the PAA solution, followed by thermal imidization and carbonisation. Imidized webs generated crosslinking and aromatic heterocyclic structures and carbonized with yields from 50% to 70%. The PI nanofiber has enormous potential value and will be a very promising precursor of carbon nanofiber.In this paper, different solid contents of BTDA-ODA Polyamic acid (PAA) solution were prepared with different solvent as DMF, DMAc and NMP. The non-woven membranes of polyimide for insulation are prepared by electrospinning the polyamic acid solution, followed by thermal imidization, carbonisation. Imidized webs were carbonized in the temperature range from 600℃to 1000℃under a nitrogen atmosphere. The images of fibers were characterized by scanning electron microscopy and transmission electron microscopy, heat-resistant quality of fibers was characterized by Thermogravimetric Analysis (TG) and phase structures were characterized by wide angle X-ray Diffraction (WAXD). The results showed that average diameter of PI nanofibers with DMF system (voltage was 15kV, receptor distance was 20cm and solid contents of solution was 25%)was the thinest from 150 to 250nm, diameter of PI nanofibers after heat treatment was from 300 to 500nm, bending, twisting and adhesion phenomenon were most serious within the fibers after imidization. however, PI non-woven membrane which prepared by PAA electrospun solution synthesized with NMP indicated a relatively high thermal stability, electrospining went again stcrystal structure of PI nanofiber, and it was little changed after heat treatment.