Determining Dry Mass Regain in Flax Roving Processing
Determining dry mass regain in flax roving requires 105°C thermal drying coupled with solvent extraction corrections to separate water loss from spinning oils.
Hysteresis Curve Flax
Moisture Relationship
Graphical data showing how a fibre absorbs and releases water differently according to its starting state describes the non-linear path of moisture movement. The hysteresis curve flax provides a visual map for technicians who must predict how the material will react to changes in the mill climate. It shows that at any given relative humidity, a sample that is drying will hold more water than one that is becoming wet.
Directional Effect
Understanding the shape of this loop allows the production manager to set the humidifiers at levels that prevent static electricity without causing the yarn to stretch. Because the hysteresis curve flax is specific to the cellulosic structure of the plant, the gap between the absorption and desorption lines is wider than in cotton. This physical property means that a mill cannot rely on simple humidity charts to guess the moisture regain.
Precise control requires measuring the actual weight of the fibre rather than the saturation of the air. The distance between the two lines represents the energy required to break the hydrogen bonds within the flax bundle.
Mill Environment
Fabric stability in the finishing plant depends on recognizing these boundaries. If the cloth is dried too aggressively, it may never return to its original dimensions even after re-wetting.