EFFECTS OF THERMAL CYCLING ON THE CRYSTALLIZATION CHARACTERISTICS OF WATER WITHIN CROSS-LINKED HYDRO-ACTIVE POLYMERIC STRUCTURES

Fully hydrated crosslinked hydrophilic polymers have been subjected to freeze/thaw thermal cycling and the crystallization of water within t hese polymers has been monitored using a simple transient thermal meth od. 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 th ermomechanical stresses occurring during ice/water formation in the co urse of freeze/thawing.