Polyphosphazene Elastomers with Alkoxy and Trifluoroethoxy Side Groups

Elastomers based on the polyphosphazene skeletal platform are the subject of broad interest from both biomedical and technological viewpoints. Here, we describe a fourth generation of polyphosphazene elastomers with both 2,2,2-trifluoroethoxy (CF₃CH₂O−) and nonfluorinated alkoxy groups such as CH₃CH₂O–, CH₃CH₂­CH₂O–, or CH₃CH₂­CH₂CH₂O– units. These structures provided access to elastomers with very low glass transition temperatures in the range of −60 to −90 °C. Variations in the relative percentages of the alkoxy and trifluoroethoxy side groups have a significant influence on the physical properties, which were studied by stress–strain, differential scanning calorimetry, and thermogravimetric analysis techniques. Biomedical materials focused on cardiovascular and dental applications are target applications.