Furthermore, the kraft process gives a much more comprehensive delignification whereas
sodium hydroxide alone, even after very long cooking times, leaves a substantial amount of residual
lignin in the fibres. The dissolution of carbohydrates, on the other hand, is not influenced
93
by the presence of hydrosulphide ions and substantial amounts of polysaccharide components
are dissolved from the fibres in both soda and kraft pulping (Figure 5.2).