Discoloration of celluloses treated with polyethylenimines
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作者:
de la Orden, MU
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机构:Univ Politecn Madrid, ETSI Ind, Dept Ingn Quim Ind & Medio Ambiente, Madrid 28006, Spain
de la Orden, MU
Matías, C
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机构:Univ Politecn Madrid, ETSI Ind, Dept Ingn Quim Ind & Medio Ambiente, Madrid 28006, Spain
Matías, C
Urreaga, JM
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Univ Politecn Madrid, ETSI Ind, Dept Ingn Quim Ind & Medio Ambiente, Madrid 28006, SpainUniv Politecn Madrid, ETSI Ind, Dept Ingn Quim Ind & Medio Ambiente, Madrid 28006, Spain
Urreaga, JM
[1
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机构:
[1] Univ Politecn Madrid, ETSI Ind, Dept Ingn Quim Ind & Medio Ambiente, Madrid 28006, Spain
[2] Univ Complutense Madrid, Dept Quim Organ IEU Opt, Madrid 28037, Spain
Celluloses treated with polyethylenimines (PEIs) suffer severe degradation in air at moderate temperatures, yielding strongly coloured materials. The discoloration was found to depend on the PEI, the pH and the solvent used in the treatment of the cellulose. To study these effects, cotton cellulose samples were treated with two PEIs, using methanol and water (at pH = 6 and pH = 11) as solvents, and the PEI-treated celluloses were subjected to thermal treatment in air. The discoloration was studied using diffuse reflectance UV-Vis spectroscopy, diffuse reflectance FTIR spectroscopy and standard colorimetry. The results were explained considering that the main source of chromophores in the degradation at moderate temperatures is the reaction between PEI amino groups and cellulose carbonyl groups to form coloured imines. (C) 2004 Elsevier Ltd. All rights reserved.