RHEOLOGICAL INVESTIGATION OF THERMOREVERSIBLE POLYURETHANE HYDROGELS
Year: 2016
Journal: Rev. Roum. Chim.
Authors: Gradinaru, LM; Ciobanu, C; Vlad, S; Bercea, M
The aim of this study was to improve the knowledge concerning the thermoreversible polyurethane hydrogels in order to provide important insights for designing in situ gelling systems for future biomedical applications. Thereby, a polyurethane sample was synthesized by polyaddition reaction of poly(isopropyl lactate) diol (PILD) and poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) diol (PPP) and 4,4'-methylene dicyclohexyl diisocyanate (H12MDI). The chemical structure and molecular characteristics were investigated by H-1-NMR, FTIR and GPC analysis and critical micelle concentration was determined by surface tension measurements. The viscoelastic properties of the polyurethane in aqueous medium were determined in dynamic oscillatory conditions as a function of temperature and the formation of the thermoreversible hydrogel was evidenced for very low heating rate. The shear flow and the creep-recovery behaviours of the hydrogel at 37 degrees C were also investigated.
