Regain Hysteresis

Molecular Constraint

Internal bond energy in cellulose or protein chains forces water molecules into different configurations depending on the prior state of the polymer. A dry fibre absorbs moisture into amorphous regions through accessible hydroxyl groups. Drying cycles remove these molecules at a different rate because internal shifts limit egress.

High crystalline content restricts the total movement of water.

Measurement Protocol

Technicians determine the moisture regain hysteresis by weighing a sample in an oven dry state before exposing it to a series of increasing humidity steps. Subsequent data collection occurs as the climate chamber cycles back through decreasing humidity levels. Equilibrium points at each interval yield distinct values for the two paths.

Plotting these results creates a characteristically shaped loop that represents the sorption profile of the textile material.

Commercial Variance

Quality control laboratories track this phenomenon to ensure consistency in weight based transactions and dimensional stability predictions for bulk deliveries. Differences between sorption and desorption states affect the calculation of conditioned mass under standard atmosphere conditions. Shipping weight disputes occasionally arise from incorrect application of these dual values to moisture correction factors.

Buyers prefer material with low hysteresis to maintain consistent physical properties during processing changes.