ISSN:
0098-1273
Schlagwort(e):
Physics
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
Our earlier results on ασ and heavy-ion-radiation damage in cellulose triacetate (CTA) are compared with those of previous authors on UV-and γ-radiation damage in the same material. Thus the common effects of these different methods of irradiation can be distinguished from those characteristic of the radiation employed. With heavy-ion radiation the production of stable radicals is accompanied by C - O cleavage. In the case of 3684Kr (1 MeV/amu) ions, the number of free radicals produced is investigated, without distinguishing the species, by using the scavenger technique in the solid phase, combined with UV spectroscopy. On the other hand, C - O cleavage is observed by IR spectroscopy, with its inherent selectivity. A statistical study shows that the experimental curves representative of the evolution of the optical transmittance ratio before and after irradiation L(N) versus the ion fluence N are of exponential type: $$ L(N) = \alpha e^{\beta N} $$ where β is a parameter related to the volume damaged by a single ion and, therefore, to the latent track size. The latter is approximated by a cylinder whose height is equal to the range of the ion. For 3684Kr8+ (1.1 MeV/amu) the track length is 21 μ. For each type, damages are localized within a radius of 250 Å for free-radical yields, 148 Å for cellulosic chain cleavages, 108 Å for deacetylation, and 100 Å for opening of pyrannosic rings. The track length is 14 μ for 1735Cl6+ (1 MeV/amu), while the radius of the cylinder in which free radicals are produced is only 80 Å.
Zusätzliches Material:
18 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1982.180200715
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