Isotherm Boundary
Textile moisture behavior during exposure to rising humidity exhibits a characteristic pathway of water vapor uptake from a completely dry state. This path, known as the adsorption branch, maps the gradual bonding of water molecules to the hydrophilic hydroxyl groups in the cellulose structure of flax. It defines the lower limit of moisture content at any given relative humidity on the sorption hysteresis loop.
Moisture Recovery
Weaving and spinning mills in southern China monitor the progression along this curve to prevent yarn breakage during high-speed mechanical processing. Moving upward along the adsorption branch occurs as dry flax fiber absorbs moisture from the humid air of the spinning room, which increases fiber flexibility. The mechanical strength of flax yarn correlates directly with this structural hydration, making monitored humidification a standard method for quality control.
It progresses until the fiber reaches equilibrium with the ambient relative humidity, though this level remains lower than that achieved when drying down from a wet state.
Equilibrium Adjustment
Industrial processors of linen fabric use moisture isotherms to calibrate their finishing and drying machinery. Because the adsorption branch represents the dry-to-wet transition, it provides the reference curve when reconditioning bone-dry yarn before weaving. This specific transition path helps mills predict the rate of yarn expansion and manage fabric dimensions.
