Studies on degradation of poly(ethylene oxide) by multistep pyrolysis/gas chromatography with a programmable temperature vaporization injector

The multistep pyrolysis/gas chromatography technique using a programmable temperature vaporization injector was used to study thermal and photochemical properties of polymers. Pure poly(ethylene oxide) (PEOX) and PEOX + 3% CoCl2 specimens, 20-mm films, were UV-irradiated (2.45 mW/cm2) for 2 and 4 h in air at room temperature and pyrolyzed/gas chromatographed at 200°C, 420°C and 500°C (Fig. 1, 2). The products evolved at 200°C included residual solvent, monomer, catalyst, polymerization additives, and processing aids. At 420°C, degradation attained maximum and the compound concentrations were maximum in PEOX UV-irradiated for 2 h. In the 4-irradiated PEOX, the 420°C chromatographic peaks were less intense. At 500°C, the intensity of the peaks rose as the irradiation time was prolonged. CoCl2 (3%) gave rise to new degradation products. At 420°C and 500°C, irradiation had negligible effect on degradation of PEOX + 3% CoCl2. Scheme 1 illustrates the major interactions accompanying thermal and photochemical degradation of PEOX in the presence of CoCl2.