CHARACTERIZATION OF PPO [POLY(PHENYLENE OXIDE)] POWDER AND MEMBRANES FROM IT BY ESR TECHNIQUE

Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) powder and the dense memb ranes prepared from it by using 1,1,2-trichloroethylene (TCE) as a sol vent were characterized by electron spin resonance (ESR) technique. It was observed that PPO and membranes have free radicals. However, in t he membrane the number of spins/g was higher than in the PPO powder re gardless of the temperature used for the preparation of the membrane. PPO and the membranes all have electron donating sites when studied by using tricyanoethylene (TCNE) solution in benzene. Hamiltonian parame ters and g values for all radicals were measured. It was noticed that the permeation rate of CH4 was less than the permeation rate of CO2. O n the other hand CH4 have higher affinity for the formation of radical s in the membrane than CO2 under similar conditions. The electron dona ting sites were maximum in the membrane prepared at room temperature.