Photodegradation of sugarcane bagasse fibers: influence of acetylation or grafting UV-absorber and/or hindered nitroxide radical on their photostability
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.
| Main Authors: | , , , , , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Sociedade Brasileira de Química
2006
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532006000400019 |
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