RADICAL DECAY AND COLOR FORMATION AT VARIOUS TEMPERATURES IN UNPLASTICIZED POLY(VINYL CHLORIDE) IRRADIATED IN VACUO AT 25C
Moldings were irradiated at ambient temperatures in vacuo with 2 Mev electrons to doses of 5.9 to 7.3 Mrad. The decay of radicals was followed by EPR spectroscopy at 80, 55, and 30 deg C while simultaneous extinction measurements were made at 300 to 700 M mu with a recording spectrophotometer. The radical decay data indicated the presence of three species at each temperature, decaying exponentially with time, with half lives of 20 min, 210 rain and 135 hr at 80 deg C, of 40 min, 400 min, and 141 hr at 55 deg C, and of 54 min, 720 min, and 3200 hr at 30 deg C. G values of 2S deg C by back-extrapolation of decay curves from the three temperatures to the end of the irradiation period. The activation energy of radical decay was found to be 4.4, 5.0, and 13.7 kcal/mole for the short-lived, intermediatelived, and long-lived radicals, respectively. The optical data has a broad absorption maximum of 500 to 550 m mu and a series of seven absorption peaks with maxima at 365, and 329--330 m mu . The concentration of the material producing the broad bands was found to be inversely proportional to the long-lived radical concentration. The finestructure peaks are consistent with literature data for a polyene chain of 16 to 17 conjugated double bonds. (auth)
- Research Organization:
- Dow Chemical Co., Midland, Mich.
- NSA Number:
- NSA-17-030587
- OSTI ID:
- 4684625
- Journal Information:
- J. Appl. Polymer Sci., Vol. Vol: 7; Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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