Comments on the measurement of cell wall water

Two important measures of fiber swelling are fiber saturation point and water retention value. The former is an actual measure of water in a cell wall. The water retention value is often used for measuring fiber swelling because it is simple and fast. This study examines how well the water retention value measures fiber swelling. The work experimentally determined the water retained between the fibers and the water pressed from the cell wall in a water retention value test. Water always remained between the fibers. For some pulps, water is pressed from the cell wall. The water retention value can therefore be higher or lower than the fiber saturation point. Application : water retention value may be an incorrect measure of fiber swelling because water is always retained between the fibers and may be pressed from the cell wall.