Preparation of carbon fiber web from electrostatic spinning of PMDA-ODA poly(amic acid) solution

摘要

Pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline (ODA) were copolymerized in a tetrahydrofuran (THF)/methanol (MeOH) mixed solvent to form a 12 wt. percent poly(amic acid) (PAA) solution. It was electrostatically spun at 13-15 kV to form a PAA web of fine fibers with diameters less than 2-3 mu m. The PAA web was heated to 150-250 deg C to induce cyclization, transforming the PAA web into polyimide (PI) web. Then, the PI web was heat-treated at 700, 800, 900, 1000 and 2200 deg C. The carbonization yield decreased monotonically from 64 percent at 700 deg C to 53 percent at 1000 deg C. The electrical conductivity of carbonized PI webs also increased with increasing heat treatment temperature, exhibiting 2.5 and 5.3 S/cm at 1000 and 2200 deg C, respectively. The tensile strength and modulus of the carbonized web were 5.0 and 73.9 MPa, respectively.