Hydrogels are one of the promising classes of polymer systems that cover numerous biomedical and pharmaceutical applications. Hydrogels have become very popular due to their unique properties, such as high water content, softness, elasticity and biocompatibility. Natural and synthetic hydrophilic polymers can be physically or chemically cross-linked to produce hydrogels. Their resemblance to living tissue opens up many opportunities for use in biomedical areas. Hydrogels are widely used for various biomedical applications − tissue engineering, molecular imprinting, immuno-isolation, as dressing materials, for drug delivery, and the like.
The aim of the presented research work is to obtain hydrogel composites, filled with gelatin, for cosmetic use, and to study the kinetics of swelling of the obtained hydrogel composites.
Spatially cross-linked polymeric hydrogels filled with gelatin were obtained by graft polymerisation of hydrophilic functional monomers in the aqueous medium. For this purpose, the process was carried out in an aqueous solution at different ratios of monomers (acrylamide (AcAm), acrylic acid (AcA)) in the presence of gelatin (initiator K2S2O8, temperature − 60oC, for 2 hours) and gelatin modified with peroxide oligomer VEP-MA (2% by weight, temperature − 80oC, for 5 hours). In the case of the modified gelatin use, the initiation of polymerization occurred due to the decomposition of immobilized peroxide groups from the gelatin molecules surface. Using gravimetric method, the study of swelling kinetics was carried out. The speed constants were determined. From the results obtained, a sharp increase in the maximum values of swelling of graft copolymers AcAm and AcA samples was observed in comparison with samples of graft polyacrylamide. This is probably due to the formation of an additional cross-linked netting between graft copolymers at the expense of the interaction centers between the functional groups of the macromolecules −NH2 and −СОOH. Composites filled with modified gelatin demonstrate storage of the mass, and hence the form, with prolonged retention in an aqueous medium. This indicates that the peroxidized gelatin has satisfactory properties of the cross-linked agent, and its optimum content in the hydrogel composite is 5% by weight.