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Journal of the Brazilian Chemical Society

versão impressa ISSN 0103-5053versão On-line ISSN 1678-4790


RUGGIERO, Reinaldo et al. Photodegradation of sugarcane bagasse fibers: influence of acetylation or grafting UV-absorber and/or hindered nitroxide radical on their photostability. J. Braz. Chem. Soc. [online]. 2006, vol.17, n.4, pp.763-770. ISSN 1678-4790.

Unbleached (SCB) and peroxide bleached (PB-SCB) sugarcane bagasse fibers were grafted with hydroxyphenylbenzotriazole UV absorber (1) and/or hindered nitroxide radical of piperidinyloxy type (3). PB-SCB fibers were also acetylated with acetic anhydride. The photosensitivity of the various fibers to UV light was comparatively evaluated using Lab color coordinates and by monitoring their UV-Visible diffuse reflectance spectra. SCB fibers were found to be photostable whereas PB-SCB fibers presented some sensitivity to UV light. The stability of SCB fibers was attributed to the presence of photostable para-hydroxyphenylpropane units in SCB lignin. The grafted and non-grafted SCB fibers showed similar behaviors against UV-Visible light whereas grafted PB-SCB were photostabilized by the presence of 2 or 4 or both. Acetylation of PB-SCB fibers induced photostabilization in addition to some photobleaching effect. The photobleaching was also revealed by fluorescence emission studies. As a consequence of these observations, SCB fibers might be considered to have a high potential for lignocellulosic materials to be used outdoors.

Palavras-chave : bagasse fibers; photodegradation; photoprotection.

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