The development of paper strength properties during chlorine dioxide ECF and alkaline peroxide TCF bleaching of kraft and soda-AQ pulps and the relation to the chemical composition of the fiber surface and inner layers was investigated. Surface and inner fiber wall layer materials were collected by mechanical peeling and analyzed by enzymatic hydrolysis and capillary electrophoretic analysis for carbohydrates and pyrolysis combined with gas chromatography and mass spectrometry for lignin. The surface layers of the fibers revealed greater chemical changes by bleaching operations than did the inner layers. Handsheets were produced and tested for strength. Correlation was found between the tensile index and hemicellulose content of the fiber surface layer.
QC 20141205