Influence of g-Ray Irradiation on the Thermal Stability and Conductivity of Polyfuran

Abstract

The g-radiation effects on the conductivity and thermal properties of polyfuran were investigated. The polymerization reaction of furan was carried out at 40 ºC in the presence of FeCl₃. Then the polymer obtained was irradiated by g-radiation at absorbed doses of 1, 5 and 10 kGy. The unirradiated and irradiated polyfuran samples were investigated comparatively for conductivity, structural and thermal properties by means of four point probe measuring system, Fourier transform infrared and thermogravimetry, respectively. The conductivities of the polymer irradiated with g-radiation seem to be smaller than that of unirradiated polyfuran. The conductivity values of the irradiated polyfuran films decreased with the rising absorbed doses of g-radiation. The TG curves showed that both unirradiated and irradiated polyfuran decomposed thermally in three stages and remained ca. 55 (unirradiated), 49 (1 kGy), 46 (5 kGy) and 40 (10 kGy) percent undecomposed at 600 ºC. The apparent activation energies were calculated by the following differential (Kissinger) and integral (Flynn-Wall-Ozawa (FWO)) methods. The activation energies of the main decomposition stage for unirradiated and 10 kGy irradiated polyfuran were found by the Kissinger method to be 351.1 and 268.9 kJ/mol, while by Flynn-Wall-Ozawa they were 360.9 and 271.0 kJ/mol, respectively.