Interaction Parameter
Accelerated deformation occurs in hydro-expansive materials when they are subjected to changing moisture levels while under a mechanical load. The mechano-sorptive coefficient quantifies the extra strain that cannot be explained by simple creep or pure swelling alone. This value captures the interaction between external force and the movement of water molecules within the wood or paper structure.
It represents a fundamental property of cellulose networks.
Structural Impact
Permanent set in the material increases every time the humidity cycles from dry to wet. In corrugated containers, the mechano-sorptive coefficient explains why boxes collapse faster in non conditioned warehouses than in environments with a steady moisture level. The internal stresses redistribute as water enters and leaves the amorphous regions of the fibre.
This microscopic shifting leads to a macroscopic loss of height. A higher coefficient indicates a substrate that is more vulnerable to failure during transport through different climate zones.
Measurement Method
Laboratory testing involves applying a constant weight to a sample while varying the surrounding air humidity. Researchers calculate the mechano-sorptive coefficient by subtracting the expected elastic and thermal movements from the total observed change in length. This metric helps engineers design more resilient packaging for sea freight.
