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Limits to expanding the PN‐F series of polyphosphazene elastomers
Author(s) -
Tian Zhicheng,
Liu Xiao,
Manseri Abdellatif,
Ameduri Bruno,
Allcock Harry R.
Publication year - 2014
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.23729
Subject(s) - substituent , gel permeation chromatography , polyphosphazene , polymer chemistry , materials science , polymer , methylene , elastomer , differential scanning calorimetry , chemistry , organic chemistry , physics , composite material , thermodynamics
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 ( 1 H‐NMR), 31 P‐NMR, 19 F‐NMR, gel‐permeation chromatography, and differential scanning calorimetry. Unlike homo‐ or mixed‐substituent fluoroalkoxyphosphazene polymers, such as [NP(OCH 2 CF 3 ) 2 ] n (a microcrystalline thermoplastic, T g ∼ −63°C, T m ∼ 242°C) or [NP(OCH 2 CF 3 )(OCH 2 (CF 2 ) x CF 2 H)] n (PN‐F, a rubbery elastomer, T g ∼ −60°C, but no detectable T m ), the new polymers are gums ( T g ∼ −50°C, but no detectable T m ) with molecular weights in the 10 5 g/mol rather than the 10 6 g/mol range. POLYM. ENG. SCI., 54:1827–1832, 2014. © 2013 Society of Plastics Engineers