Reaction of the halogenated poly(thionylphosphazene)
[NSOCl(NPCl2)2]
n
(2a), which
possesses a novel S(VI)−N−P backbone, with 2, 3, and 4 equiv of
Na[OCH2CF3], followed by
excess
nBuNH2, afforded mixed-substituent
poly[alkoxy(amino)thionylphosphazenes]
[NSO(NHnBu)(NPR2)2]
n
(6)
(a, R = 51% OCH2CF3, 49%
NHnBu; b, R = 76%
OCH2CF3, 24% NHnBu;
c, R = 95% OCH2CF3, 5%
NHnBu)
in which the polymers were regioselectively substituted with
trifluoroethoxy substituents only at
phosphorus and not at sulfur. The resulting moisture stable
polymers were structurally characterized
by 31P, 1H, 13C, and
19F NMR spectroscopy. Molecular weights were in the
range M
w = 3.3 × 104 to
1.4
× 105 and M
n = 1.9 ×
104 to 8.2 × 104 according to GPC analysis in
THF versus polystyrene standards.
The thermal transition behavior was investigated by DSC, glass
transition temperatures (T
g's)
ranged
from −30 to −14 °C, and no melt transitions were detected.
Analysis of these new polymers by TGA
showed that they were stable to weight loss up to ca. 250 °C under
nitrogen at a heating rate of 10
°C/min.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.