Synthesis and Characterization of Phenylphosphine Oxide Containing Perfluorocyclobutyl Aromatic Ether Polymers for Potential Space Applications

Article abstract of DOI:10.1021/ma035241g

A novel class of phenylphosphine oxide (PPO) containing perfluorocyclobutyl (PFCB) polymers has been developed for potential use as multifunctional materials in space environments. The reaction of p-BrArOCF=CF₂ (for Ar = phenyl and biphenyl) with tert-butyllithium affords the lithium reagent smoothly below -20 °C. Subsequent substitution with phenylphosphonic dichloride provides the first bis(trifluorovinyl ether) monomers containing the PPO group. Polymerization proceeds thermally above 150 °C to give polymers that exhibit glass transition temperatures of 169 and 224 °C, respectively, and catastrophic weight loss by TGA in N₂ and air above 450 °C (10 °C/min). Copolymerization with bis(4,4′-trifluorovinyloxy)biphenyl affords film-forming transparent thermoplastic copolymers with high T_g (>140 °C) and good thermal stability (>450 °C). Initial evaluations with ground-based simulation of atomic oxygen (AO) rich space environments indicate that the PPO group imparts significant space durability to PFCB polymers.

Full text of DOI:10.1021/ma035241g

9000
Macromolecules 2003, 36, 9000-9004
Synthesis and Characterization of Phenylphosphine Oxide Containing
Perfluorocyclobutyl Aromatic Ether Polymers for Potential Space
Applications
J ia n yon g J in ,† Den n is W. Sm ith , J r .,*,† Ch r is M. Top p in g,† S. Su r esh ,†
Sh en gr on g Ch en ,†,‡ Step h en H. F ou lger ,§ Nor m a n Rice,| J on Nebo,| a n d
Bob H. Moja zza |
Department of Chemistry, School of Materials Science and Engineering, and Center for
Optical Materials Science and Engineering Technologies (COMSET), Clemson University,
Clemson, South Carolina 29634-0973, and Triton Systems Inc., 200 Turnpike Road,
Chelmsford, Massachusetts 01824
Received August 21, 2003; Revised Manuscript Received October 4, 2003
ABSTRACT: A novel class of phenylphosphine oxide (PPO) containing perfluorocyclobutyl (PFCB)
polymers has been developed for potential use as multifunctional materials in space environments. The
reaction of p-BrArOCFdCF2 (for Ar ) phenyl and biphenyl) with tert-butyllithium affords the lithium
reagent smoothly below -20 °C. Subsequent substitution with phenylphosphonic dichloride provides the
first bis(trifluorovinyl ether) monomers containing the PPO group. Polymerization proceeds thermally
above 150 °C to give polymers that exhibit glass transition temperatures of 169 and 224 °C, respectively,
and catastrophic weight loss by TGA in N2 and air above 450 °C (10 °C/min). Copolymerization with
bis(4,4′-trifluorovinyloxy)biphenyl affords film-forming transparent thermoplastic copolymers with high
Tg (>140 °C) and good thermal stability (>450 °C). Initial evaluations with ground-based simulation of
atomic oxygen (AO) rich space environments indicate that the PPO group imparts significant space
durability to PFCB polymers.
In tr od u ction
(arylene ether)s14,15 and arylene ether heterocyclic poly-
mers designed for durability in space environments.16,17
Although long-term AO exposure experiments remain
in progress, short-term space flight studies and ground-
based space environment simulations have shown that
PPO containing polymers possess excellent AO resis-
tance.14 X-ray photoelectron spectroscopy (XPS) analysis
indicated that, after AO exposure, a dense surface layer
of phosphate was formed which inhibits further erosion
and may also promote self-healing of damage caused by
space debris.18-22 Successful commercial examples of
space polymers exist (Triton Systems, Inc.),23 such as
PPO containing polyarylene ether benzimidazole (TOR),
PPO containing polyarylene ether (COR), and low-color
PPO containing polyimide (TOR-RC).
Perfluorocyclobutyl (PFCB) aromatic ether polymers
are a unique class of partially fluorinated polymers
prepared by the free radical mediated thermal cy-
clodimerization of aryl trifluorovinyl ether monomers
in bulk or solution above 150 °C.24-27 PFCB polymers
retain many classical properties of fluoropolymers in-
cluding low dielectric constant, low surface energy,
thermal and thermal oxidative stability, and chemical
resistance, while offering many advantages, such as
improved processability, optical clarity, tailorable re-
fractive index, and thermal mechanical properties.
Polymers containing the phenylphosphine oxide (PPO)
group have been studied extensively for a number of
applications in recent years. McGrath et al. reported the
synthesis and flame-retardant properties of aromatic
polyphosphonates and arylene ether phenylphosphine
oxide containing polymers.1-5 McGrath6,7 and Cabasso8
further studied the metal complexation of phosphorus
containing polymers. Polymers containing the PPO
group are also known to exhibit excellent adhesion
properties to metal substrates9,10and miscibility with
many thermoplastic and thermosetting polymers. Due
to the noncoplanar structure of triarylphosphine oxide
and the intensely polar PdO bond, polymers containing
the PPO group are usually amorphous2 and provide low
birefringence10 and high refractive index.1 The incor-
poration of the triarylphosphine oxide moiety has
brought about an increase in solubility of polyamides
and polyimides in common organic solvents.11,12 In
addition, nonlinear optical properties of polymers bear-
ing pendent phosphine oxide group chromophores have
also been studied due to the excellent electron-accepting
ability of the PPO group.13
A notable feature of the PPO group is atomic oxygen
(AO) resistance. Connell and co-workers at NASA
Langley have developed a series of PPO containing poly-
While current PFCB programs focus primarily on
microphotonics,27 the combined extreme environment
and optical properties of these materials suggested that
they might be suitable for optical space applications
provided AO resistance could be achieved. Here we
report the incorporation of the PPO group into the PFCB
thermoplastic backbone via the synthesis of novel di-
functional monomers 4 and 8 (Schemes 1 and 2). The
synthesis of trifunctional monomer 1,1,1-tris(4-trifluo-
rovinyloxy)phenylphosphine oxide (9) has been reported
* To whom correspondence should be addressed. E-mail:
dwsmith@clemson.edu.
† Department of Chemistry and Center for Optical Materials
Science and Engineering Technologies, Clemson University.
‡ Present address: Tetramer Technologies, LLC, Clemson, SC
29631.
§ School of Materials Science and Engineering and Center for
Optical Materials Science and Engineering Technologies, Clemson
University.
| Triton Systems Inc.
10.1021/ma035241g CCC: $25.00 © 2003 American Chemical Society
Published on Web 11/08/2003

Macromolecules, Vol. 36, No. 24, 2003
Synthesis of PPO Containing PFCB Polymers 9001
Sch em e 1. P r ep a r a tion of Mon om er 4
air atmospheres. The glass transition temperatures (Tg) were
obtained from a second heating after quick cooling. The
reported Tg value was taken at the midpoint of the Cp curve.
Refractive index data were obtained at 1550 nm on thin films
(spin coated on silicon wafers from THF solution) using a
Metricon model 2010 prism coupler system from Metricon Co.
F ilm P r ep a r a tion a n d Sp a ce Du r a bility. Films were
cast from polymer solutions (ca. 20% w/w) in N,N-dimethyl-
acetamide (DMAc) or THF. Solutions were doctored onto glass
plates, dried for several hours under nitrogen at 90-250 °C,
and removed by peeling under warm running water. AO, solar
absorptivity (R), and thermal emissivity (ꢀ) tests were carried
out at the NASA Marshall Space Flight Center’s AO Beam
Facility as described elsewhere.22
Ma ter ia ls. Dibromotetrafluoroethane was generously do-
nated by The Dow Chemical Co. and purified by washing with
water and 10% sodium carbonate solution and drying over
CaCl2, followed by distillation. 4-Bromo(trifluorovinyloxy)-
benezene25 and 4,4′-bis(trifluorovinyloxy)biphenyl28 were pre-
pared as described previously and are commercially available
from Tetramer Technologies, LLC, and distributed by Oak-
wood Chemicals, Inc., Columbia, SC (see http://www.oakwood-
chemical.com). Other chemicals and reagents were purchased
from Aldrich or Fisher Scientific and used as received unless
otherwise stated.
Sch em e 2. P r ep a r a tion of Mon om er 8
P r ep a r a tion of Lith iu m Rea gen ts 3 a n d 7. A 100 mL
three-neck round-bottom flask equipped with a magnetic
stirring bar, a nitrogen inlet, a rubber septum, and an addition
funnel was charged with compound 2 or 6 (30 mmol) and dry
ether (45 mL). The reaction was cooled to -78 °C, and tert-
butyllithium (17.7 mL, 1.1 equiv) was added slowly from a
dropping funnel. After complete addition, the reaction was
maintained at -78 °C for 1 h before addition of the substrate.
Bis(4-tr iflu or ovin yloxyp h en yl)p h en ylp h osp h in e Ox-
id e (4). Phenylphosphonic dichloride (3.9 g, 20 mmol) was
added dropwise via an addition funnel into an ether solution
of aryllithium reagent 3 (40 mmol) at -78 °C. After complete
addition, the reaction was allowed to warm to room temper-
ature and stirred for 2 h. The reaction was quenched with
dilute HCl and washed with water, and the organic phase was
dried over anhydrous MgSO4. The crude product was purified
by column chromatography on silica gel using hexane and
ethyl acetate (1:1) as eluent. Monomer 4 was obtained as a
pale yellow oil in 80% yield. The analysis of 4 was as follows.
IR (neat): ν 1834 (w, CFdCF2), 1595 (s, Ar), 1496 (s, Ar), 1317
(s), 1289 (s), 1273 (s), 1204 (s), 1173 (s, PdO), 1143, 1119, 1015
previously.24 In this paper we describe new thermoplas-
tic PFCB polymers containing the PPO unit, their
copolymers with traditional PFCB-forming monomers,
and the initial evaluation of their space durability.
(w) cm-1 1H NMR (500 MHz, CDCl3): δ 7.2-7.24 (4H, d),
.
7.47-7.52 (2H, td), 7.55-7.60 (1H, td), 7.65-7.70 (2H, m),
7.70-7.76 (4H, m) ppm. 13C NMR (125 MHz, CDCl3): δ 115.9,
128.5, 128.7, 129.3, 131.5, 132.0, 132.4, 134.1, 134.4, 146.8,
157.7 ppm. 19F NMR (470 MHz, CDCl3): δ -118.6 (1F, dd),
-125.3 (1F, dd), -134.7 (1F, dd) ppm. 31P NMR (121 MHz,
CDCl3): δ 28.3 ppm. GC/MS: (M+ calcd as C22H13O3PF6 470)
m/z 469, 372, 281, 200, 152, 125, 77, 50. Anal. Calcd for
Exp er im en ta l Section
Gen er a l P r oced u r es. 1H NMR (500 MHz), proton-de-
coupled 13C NMR (125 MHz), 19F NMR (470.6 MHz), and 31P
NMR (121 MHz) spectra were obtained using J EOL Eclipse+
500 and Bruker AF-300 spectrometer systems, respectively.
Chloroform-d was used as the solvent and chemical shifts
reported were internally referenced to tetramethylsilane (0
ppm), CDCl3 (77 ppm), CFCl3 (0 ppm), and H3PO4 for 1H, 13C,
19F, and 31P nuclei, respectively. Yields refer to isolated yields
of compounds estimated to be greater than 95% pure as
determined by NMR. Infrared analyses were performed on thin
films on ZnSe plates using a ThermoNicolet Magna-IR 550
FTIR spectrometer equipped with a Nic-Plan FTIR microscope.
Thirty-two scans at a resolution of 4 cm-1 were collected for
each sample (the background was ZnSe). Gas chromatography/
mass spectrometry (GC/MS) data were obtained using a Varian
Saturn GC/MS instrument. Elemental analysis data were
obtained from Atlantic Microlab, Inc. (Norcross, GA). Gel
permeation chromatography (GPC) data were collected in THF
using a Waters 2690 Alliance system with refractive index
detection at 35 °C, and equipped with two consecutive Polymer
Labs PLGel 5 mm mixed-D and mixed-E columns. Retention
times were calibrated against Polymer Labs Easical PS-2
polystyrene standards. 19F NMR end group analysis was
performed as described earlier.25,26 DSC and TGA data were
obtained from a Mettler-Toledo 820 DSC and 851 TGA/SDTA
system at a heating rate of 10 °C/min in both nitrogen and
C
22H13F6O3P (Found): C, 56.18 (56.40); H, 2.79 (2.78).
4-Br om o-4′-(tr iflu or ovin yloxy)bip h en yl (6). This com-
pound was prepared similarly as previously reported25 (Scheme
2). Compound 6 was obtained in 50% yield as a white solid by
silica gel chromatography (hexane as eluent). The analysis of
1
6 was as follows. Mp: 53.3 °C. H NMR (500 MHz, CDCl3): δ
7.15-7.19 (d, 2H), 7.38-7.43 (d, 2H), 7.52-7.58 (dd, 4H) ppm.
19F NMR (470 MHz, CDCl3): δ -119.3 (1F, dd), -126.2 (1F,
dd), -133.8 (1F, dd) ppm. 13C NMR (125 MHz, CDCl3): δ 115.6,
117.0, 121.8, 128.0, 129.3, 131.4, 132.7, 136.9, 139.0, 146.9,
154.9 ppm. GC/MS: (M+ calcd as C14H8F3OBr 328) m/z 328,
152. Anal. Calcd for C14H8F3OBr (Found): C, 51.09 (51.62);
H, 2.45 (2.46).
Bis(4-tr iflu or ovin yloxybip h en yl)p h en ylp h osp h in e Ox-
id e (8). Phenylphosphonic dichloride (3.9 g, 20 mmol) was
added dropwise via an additional funnel into an ether solution
of lithium reagent 7 (40 mmol) at -78 °C. After complete
addition, the mixture was slowly warmed to room temperature
and stirred for 2 h. The reaction was quenched with dilute
HCl and washed with water, and the organic phase was dried
with anhydrous MgSO4 and filtered. Removal of solvents under

9002 J in et al.
Macromolecules, Vol. 36, No. 24, 2003
Ta ble 1. Selected P r op er ties for P P O Con ta in in g P F CB
Cop olym er s
wt %
Mn
Tg/°Cc Td/°Cd
polym 4, 8 10 NMR (n)a GPC (Mw/Mn)b DSC N2 air
p oly4
100
0
5050 (11)
4650 (1.49)
5660 (2.06)
169 470 468
144 458 464
143
4-co-10 50 50 7970 (20)
4-co-10 25 75 20200 (55) 16440 (3.97)
p oly8
100
0
2900 (2.98)e
224 457 422
a
b
End group analysis by 19F NMR. GPC in chloroform vs
polystyrene. c DSC at 10 °C/min in N2. 5 wt % loss. e Polymerized
d
by DSC experiment.
Sch em e 3. P olym er iza tion of P P O Con ta in in g
Difu n ction a l P F CB Mon om er s 4 a n d 8, a n d
Tr ifu n ction a l Mon om er 9
F igu r e 1. 31P NMR spectra of crude (top) and pure (bottom)
monomer 4 prepared from the Grignard reagent.
Sch em e 4. Cop olym er iza tion of P P O Con ta in in g
Mon om er s
reduced pressure afforded a viscous yellow crude product.
Compound 8 was obtained in 50% yield as a white solid by
silica gel chromatography (1:1 hexane/ethyl acetate). The
analysis of 8 was as follows. IR (neat): ν 1833 (w, CFdCF2),
1602 (s, Ar), 1516 (s, Ar), 1489 (s, Ar), 1314 (s), 1276 (s), 1193
1
(s), 1172 (s, PdO), 1140, 1122, 1005 (w) cm-1. H NMR (500
MHz, CDCl3): δ 7.17-7.22 (d, 4H), 7.47-7.53 (dt, 2H), 7.55-
7.69 (m, 9H), 7.71∼7.82 (m, 6H) ppm. 19F NMR (470 MHz,
CDCl3): δ -119.2 (1F, dd), -126.1 (1F, dd), -133.9 (1F, dd)
ppm. 13C NMR (125 MHz, CDCl3): δ 116.5, 127.1, 128.8, 129.0,
130.9, 131.8, 132.2, 132.8, 134.7, 136.8, 143.6, 144.9, 147.1,
149.2, 155.2 ppm. MS: (M+ calcd as C34H21F6O3P 622) m/z 622,
524, 427, 357, 152. Anal. Calcd for C34H21F6O3P (Found): C,
65.60 (65.40); H, 3.40 (3.55).
Resu lts a n d Discu ssion
The increasing importance of the gossamer spacecraft
has urged the development of high-performance space
polymers with optical clarity and space environment
durability.19,20 Our strategy has been to incorporate the
PPO group into a versatile class of semifluorinated aryl
ether polymers containing the PFCB linkage. Novel
PPO containing monomers 4 and 8 were prepared by
using our established intermediate strategy via aryl-
lithium chemistry (Schemes 1 and 2).29 High-yielding
lithium reagents 3 and 7 were prepared by classic
metal-halogen exchange reaction while leaving the
trifluorovinyl ether group intact. For more cost-effective
scale-up and processing, the Grignard reagent of com-
pound 2 was also prepared and reacted with phen-
ylphosphonic dicholoride to give monomer 4 in excellent
yield (90%). The Grignard reagent, however, is less
reactive than the lithium reagent, and the nucleophilic
substitution reaction yielded more byproducts as shown
by the 31P NMR spectra in Figure 1.
Aryl trifluorovinyl ether monomers undergo thermal
step growth polymerization via radical mediated cyclo-
polymerization, affording high molecular weight linear
or network PFCB polymers and copolymers depending
on the average functionality of the monomers.26 Mono-
mer 4 was homopolymerized and copolymerized with
bis(trifluorovinyloxy)biphenyl (10) at three different
compositions (Schemes 3 and 4). The GPC of homopoly-
mer p oly4 in THF (relative to polystyrene) gave a
P olym er iza tion . In a 100 mL three-neck round-bottom
flask equipped with a mechanical stirrer and a N2 inlet,
monomer 4 was homopolymerized and copolymerized with bis-
(trifluorovinyloxy) biphenyl (10) with different compositions
at 160 °C for 4 h and 200 °C for 8 h. Polymerizations were
performed in the bulk at early conversions after minimum
quantities of mesitylene were added to maintain stirring. After
polymerization, the polymers were dissolved in THF and
precipitated in methanol. The polymerization for monomer 8
was studied only in a DSC experiment. The resulting PFCB
polymers have good solubility in most common organic sol-
vents, such as THF and dichloromethane. Selected properties
are presented in Table 1. For example, the analysis of p oly4
was as follows. IR (neat): ν 1595 (s, Ar), 1498 (s, Ar), 1306 (s),
1206 (s), 1178 (s, PdO), 1120, 1095, 963 (s, cyclobutane-F6)
cm-1. 1H NMR (500 MHz, CDCl3): δ 7.15-7.22 (2H, d), 7.26-
7.32 (2H, d), 7.42-7.52 (2H, br), 7.53-7.59 (1H, m), 7.60-7.72
(6H, br) ppm. 19F NMR (470 MHz, CDCl3) shows the charac-
teristic series of multiplets representing the perfluorocyclobu-
tyl fluorine signals ranging from -126 to -133 ppm. Anal.
Calcd for (C22H13F6O3P)n (Found): C, 56.2 (56.43), H, 2.8 (2.86).
Complete characterization was carried out for p oly8 similarly
as presented for p oly4 and is consistent with the structure
proposed (Scheme 3). The refractive indexes for p oly4 and
p oly8 were measured to be 1.5395 and 1.5877 at 1550 nm,
respectively.

Macromolecules, Vol. 36, No. 24, 2003
Synthesis of PPO Containing PFCB Polymers 9003
F igu r e 4. DSC (10 °C/min) analysis of p oly4 and p oly8.
F igu r e 2. 19F NMR spectra of monomers 4 and 10 and their
copolymer in CDCl3.
F igu r e 5. TGA of p oly4 and p oly8 in nitrogen and air at 10
°C/min.
F igu r e 3. Polymerization of monomers 4 and 8 by DSC (10
°C/min).
monomodal distribution with Mw ) 7000 (Mw/Mn ) 1.5).
As summarized in Table 1, the molecular weight of the
copolymers is much higher than that of the homopoly-
mer presumably due to enhanced solubility during
polymerization. In addition, the effect of molecular
weight limiting trace impurities (e.g., monofunctional
byproducts) known to be present in monomer 4 is
diluted during copolymerization. Transparent, flexible,
and tough films with slight yellow color were obtained
from p oly(4-co-10). The molecular weight calculated
using end group analysis25,26 by 19F NMR is close to the
GPC results for the copolymers. Figure 2 exhibits the
19F NMR spectra of monomer 4, 10, and p oly(4-co-10)
(50:50 wt %). The chemical shift differences for the vinyl
fluorine signals in monomers 4 and 10 are clearly
resolved, and the spectrum for p oly(4-co-10) shows the
decrease in vinyl fluorine signals and the concomitant
increase of complicated multiplets ranging from -126
to -133 ppm, which represents the six possible perfluo-
rocyclobutyl rings (e.g., both cis and trans isomers of
4-4, 4-10, and 10-10 linkages) each containing six
nonequivalent fluorine atoms.
As shown in Figure 3, monomers 4 and 8 have very
similar thermal polymerization behavior. The onset of
thermal cyclodimerization of the aryl trifluorovinyl
ether group in 4 and 8 is detected around 140 °C, and
the exothermic peak reaches a maximum at 243 °C.
These characteristics are similar to those of other bis-
and tristrifluorovinyl ether aromatic monomers,26 which
suggestssalong with 19F NMR data indicating nearly
equal monomer consumption ratessthat the PPO group
imparts negligible influence on the PFCB thermal
cyclodimerization kinetics. In terms of enthalpy, the
F igu r e 6. TGA of p oly4 and copolymers in nitrogen and air
at 10 °C/min.
polymerization of monomers 4 and 8 is close to that of
the previously reported thermosetting PPO monomer
924 on the basis of the enthalpy per trifluorovinyl ether
group (-∆H ) 18-20 kcal/mol). Both p oly4 and p oly8
were found to be amorphous with no crystalline transi-
tions observed by DSC (Figure 4) as expected for the
stereorandom PFCB polymerization that typically af-
fords an equal fraction of cis and trans 1,2-disubstituted
cyclobutanes. The glass transition temperatures (Tg) of
p oly4 and p oly8 were found to be 169 and 224 °C,
respectively.
Figure 5 displays the TGA results for p oly4 and
p oly8 in nitrogen and air. The thermal stability of
p oly4 under air is nearly identical to that under
nitrogen below 520 °C. This result indicates that the
PPO group does not detract from the inherent thermal
stability of PFCB polymers and may indeed increase the
thermooxidative stability. The temperature at 5% weight
loss was measured to be 470 °C for p oly4 and 457 °C
for p oly8 under nitrogen. For space polymer applica-
tions in low Earth orbit (LEO), glass transition tem-
peratures and thermal and thermal oxidative stability
in this range have been sufficient. Under nitrogen and
air atmospheres, the homopolymers and copolymers
show similar catastrophic weight loss by TGA. Under
air, however, the copolymers decomposed more com-
pletely as expected (Table 1 and Figure 6).

9004 J in et al.
Macromolecules, Vol. 36, No. 24, 2003
Ta ble 2. Sp a ce En vir on m en t Sim u la tion Da ta for Selected P F CB P olym er s
solar absorptivity (R)
thermal emissivity (ꢀ)
AO fluence
(atoms/cm2)
mass loss
(wt %)
material
preexposure
postexposure
preexposure
postexposure
p oly(4-co-10)
p oly10
2.6 × 1020
2.2 (0.85)a
33.2 (8.6)a
0.163
0.144
0.193
0.164
0.680
0.565
0.650
0.411
3.88 × 1020
a
AO fluence normalized mass loss percent.
A key property of PPO containing PFCB polymers is
their expected resistance to atomic oxygen (AO) due to
the PPO content, which has been established in many
ground-simulated and space tests for the TOR materi-
als.20,23 AO is formed by the photodissociation of upper
atmosphere O2 by short-wavelength UV radiation and
is a prevalent species in LEO between the altitude of
160 and 800 km.15-17 AO is very reactive and quickly
erodes organic polymers if they are unprotected.19 AO
durability was evaluated by mass loss caused by erosion
after an AO exposure level of (2-6) × 1020 atoms/cm2
(equivalent to an exposure of 4 month duration in LEO)
and with accompanied UV irradiation comparable to
several hundred ESHs (equivalent solar hours). Table
2 presents the data for p oly(4-co-10) containing 12.5
wt % monomer 4. This copolymer gave higher quality
films for the AO tests and was similar in molecular
weight and other properties to the copolymer containing
25 wt % shown in Table 1. The copolymer experienced
only 2.2 wt % mass loss compared to 33.2 wt % for
p oly10 (without PPO), which equates to an AO fluence
normalized mass loss ratio of 1:10. These preliminary
results indicate an order of magnitude increase in AO-
erosion resistance for a PFCB copolymer containing only
12.5 wt % PPO monomer 4. The solar absorptivity (R)
relates to the quantity of incoming solar energy that is
absorbed by the film, while the thermal emissivity (ꢀ)
describes the ability of the film to radiate energy from
the surface.22 After AO exposure, the R value will
increase and the ꢀ value will decrease due to the change
of the optical transparency of the film. Incorporation of
the PPO monomer did not show a significant change in
the solar absorptivities and thermal emissivities. How-
ever, the thermal emissivities of p oly10 (without PPO)
decreased dramatically.
materials, Mettler Toledo for donation of the DSC820
and 851TGA/SDTA system, and NASA Marshal for
space environment simulation data. We gratefully ac-
knowledge Kim Ivey (Clemson University) for assistance
with FTIR data, and S. Kumar, P. Go, and H. Liu for
synthetic expertise. D.W.S. is a Cottrell Scholar of
Research Corporation.
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Con clu sion s. The reaction of p-BrArOCFdCF2 (for
Ar ) phenyl and biphenyl) with tert-butyllithium af-
forded the aryllithium reagent smoothly below -20 °C.
Upon treatment with phenylphosphonic dichloride, two
novel bis(trifluorovinyl ether) monomers containing the
phenylphosphine oxide group were successfully pre-
pared. Polymerization proceeded thermally above 150
°C and gave thermoplastic polymers that exhibited glass
transition temperatures of 169 and 224 °C, respectively.
Copolymerization with bis(4,4′-trifluorovinyloxy)biphen-
yl gave film-forming transparent thermoplastic copoly-
mers with high Tg (>140 °C) and good thermal stability
(>450 °C). Preliminary atomic oxygen resistance tests
indicated an order of magnitude increase in PFCB AO
resistance when 12.5 wt % PPO monomer was incorpo-
rated into PFCB copolymers.
(17) Connell, J . W.; Smith, J . G., J r.; Hedrick, J . L. Polymer 1995,
36, 13.
(18) Connell, J . W. High Perform. Polym. 2000, 12, 43.
(19) Connell, J . W. In Fluoropolymer 2000; Smith, D. W., J r., Ed.;
EPS: Hattiesburg, MS, 2001; p 74.
(20) Connell, J . W.; Watson, K. A. In Gossamer Spacecraft:
Membrane and Inflatable Structures Technology for Space
Applications; J enkins, C. H. M., Ed.; AIAA: Reston, VA, 2001;
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(21) Smith, J . G., J r.; Connell, J . W.; Hergenrother, P. M. NASA
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(22) Watson, K. A.; Palmieri, F. L.; Connell, J . W. Macromolecules
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(23) See http://www.tritonsys.com.
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(25) Smith, D. W., J r.; Babb, D. A. Macromolecules 1996, 29, 852.
(26) Smith, D. W., J r.; Babb, D. A.; Shah, H. V.; Hoeglund, A.;
Traiphol, R.; Perahia, D.; Bone, H. W.; Langhoff, C.; Radler,
M. J . Fluorine Chem. 2001, 104, 109.
(27) Smith, D. W., J r.; Chen, S.; Kumar, S. M.; Ballato, J .;
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(28) Babb, D. A.; Ezzell, B. R.; Clement, K. S.; Richey, W. F.;
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Ack n ow led gm en t. We thank the Air Force Office
of Scientific Research (STTR with Triton Systems, Inc.),
National Textiles Center, the South Carolina NASA
Space Grant Consortium, SC EPSCoR, and the National
Science Foundation (DMR-CAREER Award to D.S.) for
partial support, and 3M Corp. for 3M Pre-tenured
Faculty Awards (D.S. and S.F.) for financial support.
We also thank The Dow Chemical Co. for starting
(29) J unmin, J .; Narayan, S.; Neilson, R.; Oxley, J .; Babb, D.;
Rondan, N.; Smith, D. W, J r. Organometallics 1998, 17, 783.
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