Effects of thermal cycling on the crystallization characteristics of water within crosslinked hydro-active polymeric structures

Fully hydrated crosslinked hydrophilic polymers have been subjected to freeze/thaw thermal cycling and the crystallization of water within these polymers has been monitored using a simple transient thermal method. The initially large depression of the crystallization temperature (relative to the crystallization temperature of bulk water) decreased with the number of thermal cycles. This phenomenon has been attributed to a partial breakdown of the polymer network, due probably to the thermomechanical stresses occurring during ice/water formation in the course of freeze/thawing.