Preparation of New Hydrogels Based on Polyurethane/ Polyoxyethylene/Silica Components via Click Chemistry

Hydrogels are crosslinked hydrophilic polymer structures that can imbibe large amounts ofwater or biological fluids [1]. Hydrogels have been considered as promising materials in tissueengineering and biomedical area [2]. Because of its high hydrophilicity nature, polyethyleneglycol (PEG) is one of the most extensively used monomers for preparing differenttypes of hydrogels [3]. In this work, silica nanoparticles (SNP s) were homogeneously trappedinto a polyurethane (PU)-based hydrogel during its preparation (Fig. 1). The effect of the nanoparticleson the thermal behavior as well as the amounts of water uptake were thoroughlystudied. Briefly, an azide-containing and polyoxyethylene (POE)-based polyurethane (PU)was synthesized starting from PEG, ɛ-caprolactone (ɛ-CL), and methylene diphenyl diisocyanate(MDI). Next, an yne-terminated PEG was used as the crosslinker in the presence ofSNP s in 2.5, 5.0, and 10.0 wt.%. In this stage, a thermally-induced copper (I)-catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) was performed. FT-IR, XRD, 1H-NMR, FESEM,and TGA/DTG techniques were used to characterize the desired samples.