THE PENETRATION OF AQUEOUS-SOLUTIONS IN DRY GELATIN LAYERS

A technique is proposed for the investigation of the initial penetration velocity of aqueous solutions in gelatin sheets. With this technique, information can be obtained on the structural nature of gelatin sheets. The penetration rate depends on the preparation of the layers, the hardening and storage conditions, as well as on the polymers incorporated in the gelatin sheet. Polymer fillers increase the penetration when they are in a rubberlike state, and when they are linked to the gelatin matrix by physisorption or by chemisorption. High electrolyte concentration in the penetrant decreases the penetration rate. The activation energy of penetration is too high to explain this process simply by diffusion.