ISSN:
0021-8995
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Unmodified cotton fabric, cyanoethylated cottons having 0.12, 0.55, 0.77, and 1.24% N as well as cotton treated with NaOH under conditions similar to those of cyanoethylation but in absence of acrylonitrile were exposed to gamma radiation doses (3.199-31.199 Mrads). The six substrates before and after irradiation were assessed for copper number, carboxyl content, degree of polymerization, tensile strength, and elongation at break to determine the extent of degradation of these substrates. The effect of radiation dose on the nitrogen content of cyanoethylated cottons was also examined. It was found that degradation is higher the higher the radiation dose irrespective of the substrate used. Nevertheless, the extent of degradation is determined by nature of the substrate. Introduction of cyanoethyl groups in the molecular structure of cotton cellulose impart certain resistance to radiation degradation of cotton provided that these groups are present in appreciable amounts (0.55% N and above). The cyanoethyl groups seems to impede oxidation of the cellulose hydroxyls and/or glucosidic bonds against radiolysis. On the other hand, when present in smaller amounts, the cyanoethyl groups are not able to outweigh the increased accessibility of cotton cellulose brought about by the alkaline environment of the cyanoethylation reaction. Hence, substrates containing lower cyanoethyl contents are more susceptible to degradation than the modified cotton, and in this respect they are similar to alkali-treated cotton.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/app.1985.070301009
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