Hydrogels of collagen hydrolysate cross-linked with dialdehyde starch

Processing hydrogels of collagen hydrolysate (H) cross-linked with dialdehyde starch (DAS) by dipping or casting into biodegradable materials for various applications, is complicated by their marked tendency to aging. One-hour action by temperatures at 60-90 A degrees C reduces sorbed water content in hydrogels by approx. 12%; dependence of the extent of this reduction on temperature (within the mentioned range) was not detected. Effect of thermal action on duration of their disintegration in an aqueous medium and on its pH (within limits 4.8-7.4) was not found either, neither on their gel-sol transition temperature. This supports the view that aging is caused by time-dependent increasing network density of inter-chain hydrogen cross-links. The given temperature interval is satisfactory for processing hydrogels through technologies currently used in processing synthetic plastics (compression molding, injection molding).