ISSN:
0449-2951
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
Thin films of poly(methyl acrylate) at room temperature have been photodegraded in air and in vacuum by radiation from a low-pressure mercury source. Changes in intrinsic viscosities, ultraviolet absorption, and volatile products were followed as a function of the energy absorbed. Crosslinking occurs in both air and vacuum, but at a slower rate in air. The apparent quantum yield for random scission in air was 0.013 scissions per quantum absorbed. In air, carbonyl groups are formed along the backbone chain. Most of the volatile products studied appear to orginate from the ester groups in the polymer; formaldehyde, methanol, and methyl formate evolved at a constant rate for doses up to at least 2 × 1020 quanta/g.; quantum yields for each were determined. Carbon dioxide forms in amounts increasing exponentially with dose. Small amounts of carbon monoxide, methane, and hydrogen were detected qualitatively, but monomer was not observed. A mechanism compatible with these findings is suggested.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1964.100020506
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