IN VITRO INVESTIGATION OF THE BIODEGRADATION CAPACITY OF POLYURETHANE-UREAS WITH GRAFTED COPOLYMER FRAGMENTS OF POLYVINYL ALCOHOL-POLYETHYLENE GLYCOL IN STRUCTURE

The study of biodegradation capacity in vitro is one of the essential stages in the development of polymers for medical applications, as it allows predicting the behavior of the materials in vivo. Therefore, the purpose of this work was to investigate the biodegradation capacity of polyurethane-ureas (PUUs) with fragments of 4,4’-diaminodiphenylmethane (DADPh) as a chain extender and grafted copolymer polyvinyl alcohol-polyethylene glycol (PVA-PEG) as a hydrophilic component under in vitro conditions. The biodegradation capacity was evaluated based on the changes in the structure, physical-mechanical, and thermophysical properties of PUUs under the influence of biological medium 199 (BM 199) over incubation periods of 1, 3, and 6 months, using methods such as IR spectroscopy, physical-mechanical testing, and differential scanning calorimetry (DSC). Based on the results of IR spectroscopy studies, under the influence of BM 199, a process of biodegradation of the studied PUUs occurs, which is accompanied by the cleavage of chemical bonds, changes in hydrogen interactions, and structural transformations of the polymer matrix. Based on physical-mechanical tests, after 6 months of incubation, a decrease in strength of 11.9–26.7% and in relative elongation at break of 5.9–13.7% was observed in PUUs compared to the control. DSC analysis revealed that after 6 months of incubation in BM 199, an increase in Tg of 10.6–51.3% and an increase in ΔCp during vitrification of 17.5–46.5% were observed, indicating structural changes during the biodegradation process. Considering the obtained results, the investigated PUUs with DADPh fragments and graft copolymer PVA-PEG in the structure demonstrate biodegradation capacity in vitro with simultaneous structural changes in the polymer matrix. The synthesized PUUs could be a promising polymer matrix for developing bioactive polymer materials with temporary functionality and require further investigation.