Fluorinated waterborne shape memory polyurethane urea for potential medical implant application

A series of crosslinked fluorinated waterborne shape memory polyurethane urea (PUU) ionomers were synthesized from polycaprolactone diol, perfluoropolyether (PFPE) diol, dimethylolproionic acid, isophorone diisocyanate, ethylenediamine (EDA), and diethylenetriamine (DETA). The effect of PFPE content in the soft segment and the degree of crosslinking on the molecular structure and the properties of these PUU films was examined and studied. Differential scanning calorimetry showed that the transition temperature for these Tm type shape memory PUU could be fine tuned by PFPE weight percentage and EDA/DETA ratio in the range between 33 and 44 degrees C, covering the range of body temperature. Although incorporating amorphous fluorinated units into semicrystalline soft segment compromised the shape memory performance of PUU with linear structure as expected, the introduction of crosslinking structure using DETA as a trifunctional chain extender could still retain quite high strain recovery rate (above 90%) at 100% stretching deformation. Furthermore, the relationship of these properties as well as thermal stability with hydrogen bonding was also discussed by evaluation of the carbonyl stretching region in Fourier transform infrared spectra. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012