Limits to Expanding the PN-F Series of Polyphosphazene Elastomers

作者：Tian Zhicheng; Liu Xiao; Manseri Abdellatif; Ameduri Bruno; Allcock Harry R^*

来源：Polymer Engineering and Science, 2014, 54(8): 1827-1832.

DOI：10.1002/pen.23729

Mixed-substituent fluoroalkoxyphosphazene polymers bearing 15% 1H,1H,2H,2H-perfluorooctan-1-oxy or 1H, 1H,2H,2H-perfluorodecan-1-oxy side groups together with trifluoroethoxy cosubstituent groups were synthesized. The low reactivity of the long-chain fluoroalkoxides and their limited solubility in organic solvents prevented higher levels of substitution. Moreover, the sodium alkoxides with two methylene residues adjacent to the oxygen proved to be unstable in solution due to elimination of NaF and precipitation of side products, and this limited the time available for chlorine replacement reactions. The resulting cosubstituent polymers were characterized by proton nuclear magnetic resonance (H-1-NMR), P-31-NMR, F-19-NMR, gel-permeation chromatography, and differential scanning calorimetry. Unlike homo- or mixed-substituent fluoroalkoxyphosphazene polymers, such as [NP(OCH2CF3)(2)](n) (a microcrystalline thermoplastic, T-g -63 degrees C, T-m similar to 242 degrees C) or [NP(OCH2CF3)(OCH2(CF2)(x) CF2H)](n) (PN-F, a rubbery elastomer, Tg 60 C, but no detectable the new polymers are gums (T-g similar to -50 degrees C, but no detectable T-m) with molecular weights in the 10(5) g/mol rather than the 10(6) g/mol range.

• 出版日期2014-8