Thermal Degradation Behavior of Polyaniline in Polyaniline/Tunsten Carbide Composite

摘要

Polyaniline/tungsten carbide (PANI/WC) composite was synthesized by chemical oxidative polymerization of aniline using ammonium persulfate as the oxidant and thermal treated in air at 150°C,250°C,350°C and 450°C to 2 hours.The changes of structure,crystalline and conductivity were investigated by Fourier Transformed Infrared (FT-IR),Fourier Transformed Raman (FT-Raman),X-Ray Diffraction (XRD) and four-probe technique.The results showed that PANI/WC composite showed much-improved thermal stability compared to pure PANI.But the conductivity of PANI/WC is reduced to some extent (1.73 S/cm,the conductivity is reduced by about 82％) after thermal treated at 250°C,and dropped by 6 orders of magnitude (3.25× 10-6S/cm) at 350°C.This may be explained by that only a fraction of dopant losses during thermal treatment at 250°C,but after thermal treatment at 350°C,along with cross-linking,chain scission and oxygen,resulting in destruction of crystal structure,decrease of the emeraldine sequence.