No abstract

An experimental study comparing radiation-induced degradation of poly (methacrylates) from ultraviolet, gamma-ray ( 60Co), and electron-beam irradiation is presented. Analytical techniques used include mass spectroscopy, low-temperature electron paramagnetic resonance, and infrared spectrometry. The poly(methacrylate) polymers investigated are poly(methyl methacrylate) (PMMA), poly(t-butyl methacrylate) (PBMA), poly(methacrylic acid) (PMA), and poly(methacrylic anhydride) (PMA AN). All are shown to exhibit scission of the main chains and removal of the side groups when irradiated.

The photochemistry of furfural (furan-2-carboxaldehyde) has been studied in the vapor phase by direct irradiation at a number of wavelengths from 3130 to 2225 Å as well as by sensitization by Hg(3P1) atoms. The products that were obtained were furan, methylacetylene, allene, cyclopropene, and carbon monoxide. The quantum yield for decomposition was ∼5 × 10−3 at 2225 and 2654 Å and was equally small in the first absorption region at 3130 Å. Two primary processes are proposed, one of which may lead to furan and CO by a hydrogen migration, and the other to C3H4 + 2CO. The possibility exists that the latter process proceeds through an excited molecule of furan as an intermediate. Evidence is presented which suggests that much of the observed photochemistry involves a low energy triplet of furfural.

No abstract