The synthesis and curing kinetics study of a new fluorinated polyurethane with fluorinated side chains attached to soft blocks

Article abstract of DOI:10.1039/c5nj01772f

Fluorinated polyurethane (FPU) with fluorine in the side chain was obtained using fluorinated polyether glycol (FPO) with fluorinated side chains and 4,4′-diphenyl methane diisocyanate (MDI). The direct visual inspection of microstructures by SEM revealed that the separation degree of soft and hard segments decreased with the introduction of fluorinated groups into polyurethane soft segments, leading to a decrease in the crystallinity of FPU. The glass transition temperatures (T_g) measured by DMA indicated that the optimal working temperature window of FPU separating soft and hard glass transitions became narrow. And the mechanical properties and surface properties of the FPU were also measured. Curing kinetics of FPU was studied using a rotational rheometer, and the activation energy of FPU was obtained. The relationship between the curing temperature and the mobility of fluorinated groups was characterized by XPS. The result showed that F content in the FPU surface decreased with increasing curing temperature.

Full text of DOI:10.1039/c5nj01772f

View Article Online
View Journal
NJC
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: L. Li, X. Wang, Z.
Li, Y. Li, Y. Qi and Q. Dong, New J. Chem., 2015, DOI: 10.1039/C5NJ01772F.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/njc

Page 1 of 11
New Journal of Chemistry
View Article Online
DOI: 10.1039/C5NJ01772F
Journal Name
RSCPublishing
ARTICLE
The synthesis and curing kinetics study of a new
fluorinated polyurethane with fluorinated side chains
attached to soft blocks
Cite this: DOI: 10.1039/x0xx00000x
Lingling Li a,b,Xia Wang b*,Zan Li c , Ying Li b*, Yuanchun Qi a, Qingzhi Dong a*
Received 00th January 2012,
Accepted 00th January 2012
DOI: 10.1039/x0xx00000x
Fluorinated polyurethane (FPU) with fluorine in the side chain was obtained using fluorinated
polyether glycol (FPO) with fluorinated side chains and 4,4'ꢀdiphenyl methane diisocyanate
(MDI). The direct visual inspection of microstructures by SEM revealed that the separation
degree of soft and hard segments decreased as the introduction of fluorinated groups into
polyurethanes soft segments, leading to a decrease in the crystallinity of FPU. The glass
transition temperatures (Tg) measured by DMA indicated that the optimal working temperature
window of FPU separating soft and hard glass transitions became narrow. And the mechanical
properties and surface properties of the FPU were also measured.Curing kinetics of FPU was
studied by rotational rheometer, and the activation energy of FPU was obtained. The
relationship between the curing temperature and mobility of fluorinated groups was
characterized by XPS. The result showed that F content in the FPU surface decreased with
increasing curing temperature.
www.rsc.org/
perfluoropolyether (PFPE) and polyꢀεꢀcaprolactone (PCL) as soft
blocks via different polymerization procedure. They found that the
strong incompatibility between hydrogenated and fluorinated
Introduction
Polyurethanes (PUs) are used in a wide variety of applications,
such as protective coatings, elastomers, sealants, adhesives, and
foams.1ꢀ6Also, fluorinated polyurethanes (FPUs), which incorporate
fluorinated blocks into the molecular chains, not only maintain most
of the outstanding properties of PUs, but also offer many useful and
desirable features, such as unique surface properties, high thermal
stability and chemical resistance. 7ꢀ10
components and between lowꢀpolar soft segments (PCL) and polar
hard blocks was an effective driving force promoting the microphase
segregation. And polymerization procedure was a key parameter for
ruling the composition of polymeric chains, but it had little effect on
the surface properties. Tao Liu, et al.23synthesized fluorinated
polyurethane fluorineꢀcontaining pendent groups in soft segments
using polybutyleneadipate (PBA) to be compounded with fluorinate
polyether diol (PFGE) as the softꢀsegment of FTPU. Fluorine can be
enriched on the surface during processing resulting in the high
content of fluorine on the surface, and the surface tension
significantly decreased. R. P. Jia, et al.24used polyetherpolyol
containing fluorine in the side chain and polytetramethylene ether
glycol (PTMEG) as soft segment to obtain fluorinated polyurethane,
However, the properties of fluorinated polyurethanes were strongly
dependent on the mass ratio and segment compatibility of the mixed
softꢀsegment.
Fluorocarbon chains have been incorporated into polyurethanes
by fluorinated diisocyanates, chain extenders, polyether glycols,
polyester glycols and endꢀcappers. 11ꢀ17However, because of the
higher syntheticcost, fewer varieties of fluorinated diisocyanates,
and lower molecular weight of fluorinated alcohols, the
improvement of properties of fluorinated polyurethane prepared was
not significant compared with hydrogenatedpolyurethane.8,18Now,
most FPUs are synthesized by fluorinated polyether glycols as soft
segments. Yoon S.C, et al.19.20proposed that the soft segments have
higher mobility and easily migrate to the surface region at room
temperature. P. F. Liu, et al.21synthesized FPUs with fluoropolydiol.
Owing to the high amount of fluorinated blocks in the mainꢀchain of
the polymer, FPUs have excellent mechanical properties, low surface
tension and high temperature performance. M. Castellano, et al.22
A number of studies have been carried out on the structure,
morphology, and properties of FPUs. Nevertheless, only a few
studies have been published on the curing kinetics of FPUs.
Owing to the low polarizability and strong electronegativity of
the fluorine atom, the reactivity of hydroxyꢀterminated
synthesized
a
series of fluorinated polyurethanes using
This journal is © The Royal Society of Chemistry 2013
J. Name., 2013, 00, 1-3 | 1

New Journal of Chemistry
Page 2 of 11
View Article Online
ARTICLE
Journal Name
DOI: 10.1039/C5NJ01772F
were almost the same as these of the fluorinated polyether glycol,
except using 1ꢀPA instead of TFP.
fluorinated polyether glycols is surely different from the
conventional polyether diols 25,26. Leonid
，
et al.27studied the
urethane reactions of cycloaliphatic and aromatic diisocyanates
with hydroxylꢀterminated fluoropolyethers (FPEs). They
proposed that the FPEs diols were attributed to the autocatalysis
of isocyanateꢀhydroxyl reaction, and also, the reactivity with
diisocyanates strongly depended on the structure of FPEs and
their molecular weights. S. Turri et al.28studied the catalyst
Synthesis of fluorinated polyurethane and hydrogenated
polyurethane
The fluorinate polyurethane (FPU) was synthesized using FPO
as soft segments, MDI as hard segments and BDO as a chain
extender. Under nitrogen atmosphere at 50 oC, the stoichiometric
amount of MDI was added into a fourꢀnecked flask equipped with a
heating mantle, a mechanical stirrer, and a thermometer. After
dissolution，FPO was added dropwise into fourꢀnecked flask. The
temperature was raised to 80 oC and kept for 3 h. Then the
temperature was reduced to 40 oC. The stoichiometric amount of
chain extender was added dropwise. Finally the polymers were dried
in vacuum at70 oC for 16 h. The reaction completion was monitored
by the absence of IRꢀ free NCO group at 2270 cmꢀ1. The whole
reaction processes are depicted in Scheme 1. Hydrogenated
polyurethane (HPU) was also obtained for comparison purpose. The
synthetic process and reaction conditions were the same as these of
fluorinated polyurethanes, except using HPO as the soft segment.The
material composition and molecular weights were listed in table 1.
effect on the crosslinking kinetics of fluorinated polyurethane
.
The aim of this investigation was to elucidate thecuring kinetics
of FPU and the relationship between the curing temperature and
mobility of fluorinated groups. In order to carry it out, firstly,
we prepared fluorinated polyether glycol with fluorineꢀ
containing side chains (FPO) via “living/controlled” cationic
ringꢀopen polymerization of tetrahydrofuran (THF) and
fluorineꢀcontaining epoxy compounds (FO). Then FPU with
fluorineꢀcontaining pendent groups in soft segments was
obtained using FPO as soft segment. The morphology,
dynamics, crystallization, thermal properties and Surface
properties of FPU were investigated. Last but not least, curing
kinetics of FPU was studied by the rotational rheometer. And
the effect of curing temperature on mobility of fluorinated
groups was studied by Xꢀray Photoelectron Spectroscopy(XPS).
NaOH
Cl
R
CH2OH
R
O
O
+NaCl
+
O
BF3 OEt2
CH2OCH2-R
R
O
O
+
H
OCHCH2OCH2CH2CH2CH2O
H
OHCH2CH2OH
O
n
Experimental
CH2OCH2-R
OCHCH2OCH2CH2CH2CH2O
H2
C
H
H
n
N
C O
+
O
C
N
Materials
MDI
Diphenylꢀmethaneꢀdiisocyanate (MDI, Sigma, USA), and 1,4ꢀ
Butanediol (BDO, AR, Shanghai, China) were distilled under
vacuum and dried over 4 Ǻ molecular sieves. THF (AR, Shanghai,
China) was kept for 48 h over KOH pellets to remove peroxide.
After filtration, the THF was heated over sodium for 12 h and then
distilled. Ethylene glycol (EG) was distilled twice. Methylene
chloride (AR, Shanghai, China) was washed three times with
concentrated sulfuric acid to remove unsaturated impurities and then
washed several times with water, a 5% solution of NaHCO3, and
again with distilled water. After drying for 24 h over CaCl2, the
methylene chloride was distilled over CaH2 and kept in a vacuum
ampoule over fresh CaH2. The 2,2,3,3ꢀtetrafluoroꢀ1ꢀpropanol (TFP,
Sigma, USA),1ꢀpropyl alcohol (1ꢀPA) and epichlorohydrin (ECH)
(AR, Shanghai, China) were used as supplied. Initiator BF3·OEt2
(AR, Shanghai, China) was used after purified by vacuum
distillation.
O
H
O
CH2OCH2-R
H2
C
H2
C
H
N
C
OCHCH2OCH2CH2CH2CH2O C
N
N O
C
n
O
C N
Thermocuring
BDO
O
CH2OCH2-R
O
O
C
H2
C
H2
C
H
H
H
H2N
y
N C OCHCH2OCH2CH2CH2CH2O
N
N
C
O
CH2 OH
4
X
y
Z
hard
soft
hard
R=CF2CF2H
FPU
R=CH2CH3
HPU
Scheme 1. The reaction process of FPU and HPU
Synthesis of fluorinated polyether glycols and hydrogenated
polyether glycols
Stoichiometric amounts of the ECH and cyclohexane (as waterꢀ
carrying agent) were charged into the 3ꢀnecked round bottom flask
equipped with a mechanical stirrer under a dry nitrogen atmosphere.
When the temperature was raised to 80 oC, NaOH and TFP were fed
dropwise in 2 h. The reaction mixture was kept for another 3 h at 80
oC. Fluorinated epoxy compound (FO) was obtained after purified by
vacuum distillation.29 Fluorinated polyether glycol (FPO) was
prepared by slowly adding FO to the reaction mixture containing
bulk THF, EG and BF3·OEt2 under nitrogen at 0 °C in a glass flask
and kept for 5 h. Then FPO was obtained after washing and
distillation.30 Hydrogenated polyether glycol (HPO) was also
prepared, the synthesized process and reaction conditions of HPO
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

Page 3 of 11
Journal Name
New Journal of Chemistry
View ArticAle ROnTliInCeLE
DOI: 10.1039/C5NJ01772F
Table1The material composition and molecular weights
Molar
HPO(FPO)/MDI/BDO
ration
Soft segments(Mn)
(g/mol)
Hard segment
Wt.ꢀ%
×104
Material
MWD GPC
GPC
Mn
(g/mol)
HPU
FPU
1/3/2
1/3/2
HPOꢀ650
FPUꢀ670
53.6
47.2
2.16
3.17
3.10
2.70
nickelꢀfiltered Cu Kꢀradiation (k = 0.154 nm) at an operation voltage
of 40 kV and 30 mA, scan rate is 5o/min.
Measurements
FTIR analysis
The thermal stabilities analysis
The composition of the synthesized FPU was analyzed with
Fourierꢀtransform infrared spectrometer (FTIR) spectra (Perkin
Elmer, SPECTRUM 100). The specimen was prepared by casting
the polymer solution film on KBr discs. 32 scans were averaged for
each sample in the range of 4000ꢀ400 cm ꢀ1 at resolution of 4 cmꢀ1.
The thermal stabilities FPU and HPU were carried out using a
Perkin Elmer（PE）Pyris TGA thermo gravimetric analyzer from
room temperature to 800 oC at 10 K/min heating rates with N2
protection, the weights of sample are 3ꢀ8 mg in all cases.
Tensile properties analysis
1H NMR and 19 F measurements
The tensile properties of FPU and HPU were measured
using a Materials Testing Machine at room temperature and
relative humidity of 50%. A crossꢀhead speed of 10mm/min
was used to determine the ultimate tensile strength and modulus
as well as the elongation at break. The results reported are the
mean values for five replicates.
1H NMR and 19F NMR was recorded on a Bruker AC 400
NMR spectrometer with tetramethylsilane (TMS) as internal
standard and deuterated dimethyl sulphoxide (DMSOꢀd6) as solvent.
GPC analysis
Surface properties analysis
The molecular weights of HPU and FPU were
characterized using PLꢀGPC50 GelꢀPermeation Chromatograph
(GPC) with DMF as eluent at a flow rate of 1.0 ml/min. The
measurement was carried out at 50 oC.
The surfaces properties of the HPU and FPU were analyzed by
XPS and contact angles. XPS (PHI 5000 Versa Probe, Japan)was
equipped with monochromated AlKa Xꢀray source (15 kV, 25 W)
and takeꢀoff angle of 45owas used with Xꢀray source.
SEM analysis
The contact angles (DSA 30 KRUSS, Germany) were measured
by the sessile drop method using telescoping goniometers at room
temperature. 5ꢀ10 ꢁL distilled water was pumped from
a
The fracture morphologies of FPU and HPU were assessed
using Sꢀ4800 field emission scanning electron microscope (FESEM;
Hitachi, Japan). Samples were treated under liquid nitrogen before
observation.
microsyringe onto the surfaces of the HPU and FPU film, the image
was captured using a telescope fitted with a video camera. All the
results were expressed as the average value of at least five
independent measurements.
Thermal Characterization
Curing kinetics analysis
The thermal response of HPU and FPU was characterized
using a PE 8500 differential scanning calorimeter. The response
was measured over a temperature range of ꢀ50 to250 C at a
heating and cooling rate of 10 K/min under a nitrogen flow of
50 mL/min.
The curing kinetics of HPUs and FPUs were performed in an
Haake MarsꢀⅢrotational rheometer (Thermo Scientific, Germany)
with a coneꢀplate geometry (diameter of 20 mm, gap of 0.5
mm).Oscillatory measurement was oscillatory time sweep, t=15min.
The oscillation frequency was 1Hz.
o
Dynamic mechanical analysis (DMA)
Dynamic mechanical properties were measured on a dynamic
mechanical thermal analyzer (NETZSCH, DMA 242). All the
samples were measured with compression mode at a heating rate
of3K/min, DF/CSF is 3.00N/0.30N. at a frequency of 1 Hz over a
temperature range ꢀ80-200 oC. The sample size was
1.6×5.6×7.8mm3.
X-ray diffractograms analysis (XRD)
Xꢀray diffractograms analysis was performed on a D8 Advance
apparatus (Bruker, Germany) in the range of 2θ = 5ꢀ40o, with a
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 3

New Journal of Chemistry
Page 4 of 11
View Article Online
ARTICLE
DOI: 10.103J9o/Cu5rNnJa0l1N77a2mF e
-CF2-
Results and discussion
-CF2H
FPU structure characterization
114
112
110
(a)
108
106
104
1205
102
(b)
100
2862
-100
-110
-120
-130
-140
-150
-160
3305
2958
ppm
98
96
94
92
90
88
86
1704
672
Fig. 3 19F NMR spectrum of FPU.
1225
798
1
The H NMR spectrum of FPU is shown in Fig. 2. It is evident
that the peak appears at 9.5 ppm, which is assigned to the protons of
ꢀOCONHꢀ. The peaks at 6.33ꢀ6.25 ppm are relative to the
fluoromethenyl protons (ꢀCHF2), the peaks at 1.51ꢀ1.69 ppm
assigned to the ꢀOCH2CH2CH2CH2Oꢀ protons of BDO, THF. The
1107
4000
3500
3000
2500
2000
-1
1500
1000
Wavenumber (cm
)
Fig. 1 FTIR spectra of (a) HPU (b) FPU.
peaks at 3.68ꢀ3.88ppmdealing with –OH2CCH(O)ꢀCH2Oꢀ,
ꢀ
The FTIR spectrums of HPU (a) and FPU (b) are show in Fig. 1.
In the spectrum, there are characteristic peaks of NꢀH (3305 cmꢀ1).
The characteristic bands at 1704cmꢀ1, 1107cmꢀ1 confirm the carbonyl
group of urethane, ether (CꢀOꢀC) of the ester group. There are CꢀH
aliphatic stretches bands at 2958，2862cmꢀ1. Compared with Fig.1
(a), the absorption bands dealing with the vibration absorption of Cꢀ
F bond are observed from Fig.1 (b).The stronger characteristic
absorption bands locating at 1225，1205 cmꢀ1 can be attributed to
stretching vibrations of ꢀCF2.31,32And a combination of rocking and
wagging vibration of CF2 group at 798，672 cmꢀ1 in the fingerprint
region is detected. It can be concluded that F has been introduced
into polyurethane. In addition, the absorption bands of the NCO
group (2270 cmꢀ1)and the OH group (3340 cmꢀ1) are not found in the
spectrum.
OCH2CF2 protons and the peaks assigned to the ꢀOCHꢀ protons (5.0
1
ppm) are also observed in the H NMR spectrum of FPU. The peak
at 3.95 ppm is assigned to the protons of –COOCH2ꢀ. The peak
appears at 7.37ꢀ7.09 ppm is assigned to the protons of phenyl. And19
F NMR (Fig.3) for FPU shows two different peaks remarkably. The
resonant absorbance of fluorine inꢀCF2ꢀ group shifted to ꢀ126.4 ppm.
The resonance of the fluorine in ꢀCF2H is observed at about ꢀ140.8
ppm. The results of 1H NMR and 19 F NMR indicate that FPU based
MDI and FPO has been prepared successfully.
Microstructures of HPU and FPU
n
q
p
O
C
O
O
C
CH2OCH2CF2CHF2
H2
C
H
N
H
N
g
OCH2CH2CH2CH2-OH
n
HNC OCHCH2OCH2CH2CH2CH2
O
m
j
l
k
f
e
i
h
d
c
b
a
k
DMSO
l+n+p
a
b+c+i+j
Fig.4 SEM fracture surface of (a) HPU and (b) FPU
h+d
f
In this study,SEM was used to understandthe bulk morphology
of fluorinated polyurethane. Fig.4. displayed the SEM images of
fractured surfaces ofHPU and FPU. All samples exhibit typical
microphase separation morphology with dispersed hard domains in a
continuous soft phase as is reported.33It can be seen that the image of
the HPU displays numerous micronꢀsized particles on the fracture
surfaces. When F was introduced into soft segment, the size of
particles decreased, meanwhile the intermediate phase interface
became smoother, indicating that the compatibilityofthe fluorinated
soft and the hard segments was enhanced. This is because that
fluorine with strong electro easily form hydrogen bond with NꢀH of
the urethanes groups, leading to the enhancement of interactions
e+g
q
m
12
10
8
6
4
2
0
ppm
Fig. 2 1H NMR spectrum of FPU.
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

Page 5 of 11
Journal Name
New Journal of Chemistry
View ArticAle ROnTliInCeLE
DOI: 10.1039/C5NJ01772F
between soft and hard semgent , and decrease of degree of
microphase separation.34It is believed that the introduction of polar
group into the side chains has an influence on the formation of Hꢀ
bond within PU, thereby affecting the microphase separation.35
(b)
Peak=124.10o
C
Area=23.800m J
D elta H =3.9666 J/g
FPU
O nset=106.8o
C
Peak=141.89o
C
XRD analysis
200
Area=61.172m J
Delta H=6.4392 J/g
H PU
Onset=111.3o
C
150
100
120
140
oC
160
Tem perature
（
）
100
Fig.6 DSC thermogrames of HPU and FPU(a)DSC curve,(b) the
HPU
magnified graph of endothermic peaks at higher temperature.
50
FPU
The DSC heating curves of HPU and FPU are shown in Fig.
6(a). the Fig.6 (b) showed the magnified graph of endothermic
peaks. The enthalpy H was determined by integration of the peak
areas. The Tg and other thermal characteristics results are
summarized in Table 2.It can be seen that Tg of soft segment is
observed in each sample. At higher temperatures, the existence of
minor endothermic peaks results from the dissociation of domains
containing longꢀrang order. 37And the melting peak relatively
decreases after introducing fluorine on the soft segments. This result
indicates that in FPU the association of domains with longꢀrange
order becomes much lower. In the cooling scans (dotted lines in
Fig6), no exothermic peak is observed in any of the materials,
indicting the low degree of hard segment crystallinity, which is
consistent with the results of XRD.
0
10
20
30
2θ
Fig.5 XRD patterns of HPU and FPU
Fig.5. shows the XRD patterns of HPU and FPU samples at room
temperature. The feature at 21 o as diffraction peaks observed for
polyurethanes arising from crystallinity in the hard domains36. It can
o
be found that 2θ at 21 becomes decreasingly evident for FPU,
suggesting that the introduction of F into soft segments decreases the
level of the degree of crystallinity in the polyurethane. However,
they are much subtler than the diffraction patterns, indicating very
low degree of hard segment crystallinity arising from ordered urea
linkages.
Table 2 The analytical result of DSC and DMA
Transition temperatures and enthalpies in
DSC
The storage and loss modulus(Tg+50oC); dissipation factor and
glass transition temperature in DMA
Tgsoft (oC)
4.2
Tm (oC)
141.9
△
H (J/g)
6.4
Tg soft(oC)
31.4
Tg hard (oC)
156.6
E′(MP)
6.4
E″(MP)
1.2
HPU
FPU
7.5
124.1
4.0
38.2
139.8
3.8
1.0
DSC analysis
Dynamic mechanical analysis
30
70
60
(a)
Tg
25
20
15
10
5
E' andE"of HPU
E' andE"of FPU
FPU
(a)
50
40
30
20
10
Tg
HPU
0
55
50
45
40
35
30
25
20
15
10
5
0
-40 -20
0
20
40
60
80 100 120 140 160 180 200 220 240
Temperature(oC)
0
-5
-40
-20
0
20
40
60
80
120
140
160
180
200
o100
Temperature( C)
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 5

New Journal of Chemistry
Page 6 of 11
View Article Online
ARTICLE
Journal Name
DOI: 10.1039/C5NJ01772F
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Mechanical properties analysis
HPU
FPU
(b)
0.3
0.2
0.1
5
HPU
4
3
2
1
0
FPU
100
120
140
Temperature
160
180
(o
C)
-40
-20
0
20
40
60
80
100
120
140
160
180
200
Temperature (oC)
Fig.7 DMA analysis comparison between HPU and FPU: (a)the
modulus vs temperature (b) tanδvs temperature
0
10
20
30
40
50
60
70
80
90
100 110 120
strain（%）
Dynamic mechanical analysis provides information on glass
transition and the mechanical behavior of a polymer. The dynamic
mechanical properties of HPU and FPU are shown in Fig. 7. From
the modulus vs temperature curves (Fig. 7(a)), the storage modulus
and loss modulus in theglassy plateau region of HPU are higher than
that of FPU. In order to better understand the effect of fluorinated
side chain on the phase separation, the rubber plateau modulus (at
temperature Tg+50 oC) is listed on Table 2. It can be observed that an
increased rubber plateau storage modulus for HPU but a decreased
rubber plateau storage modulus for FPU. The increase in storage
modulus of HPU is believed to be the formation of more continuous
hard phase morphology. The decreased storage modulus of FPU
indicates enhanced phase mixing as introducing fluorinated side
chain into polyurethane.38,39
Fig. 8 Strainꢀstress curves of HPU and FPU
The changed degree of phase separation or mixing can be also
reflected from tensile properties, since the tensile strength is
remarkably affected by twoꢀphase structure of polyurethanes. Fig.8
showed the stressꢀstrain curves of HPU and FPU. It can be found
that a decreased ultimate tensile strength and modulus (the slope),
but an increased elongation at break after introducing fluorinated
side chain on the soft segment. The decrease in tensile strength
should be due to the lower crystalline order, which is consistent with
the results of DSC. And also, from above DMA results, the
increased tensile strengths in HPU can be understood as due to the
increased phase separation, and the decreased tensile strengths in
FPU is due to the increased phase mixing. 41
On the other hand, polyurethane has two phases. The glass
transition temperatures (soft segment and hard segment) of these two
phases are very important characteristics of the interaction between
soft segment and hard segment. Different from the results of DSC,
all the samples exhibited two loss peaks corresponding to the glass
transition temperatures of soft segment and hard segment (Fig 7 (b)).
The Tg obtained from DMA for HPU and FPU are somewhat higher
than the DSC Tg, as expected from the dynamic nature of DMA
experiments.In comparison with the loss peaks of HPU, the loss
peak of FPU corresponding to soft segment is shifted toward higher
temperature, the loss peak of hard segment is shifted toward lower
temperature, resulting in the increase in Tg of soft segment and
decrease in Tg of hard segment. The result can be considered that the
introduction of F into soft segment enhances interactions between
soft and hard segments, leading to the reduction of the extent of
microphase separation. In addition, the constraint given by the hard
phase reduced the degree of freedom of the soft chains. Thereby the
onset of largeꢀscale motion of a polymer near Tg requires a higher
energy, increasing the value of tan δ peak.35,40
Thermal stability analysis
100
FPU
HPU
80
60
40
20
(a)
0
0
-5
-10
-15
(b)
-20
100
200
300
400
500
600
700
o
Temperature
(
C
)
Fig. 9 TGA analysis comparison between PU and FPU: (a) TGA and
(b)DTG curves
Table3 Thermal stability of HPU and FPU
Weight remained (%)a
sample
Temperature (oC)b
300oC
94.7
400oC
24.9
500oC
4.7
T10
317
340
T50
362
398
Thard max
350
Tsoft max
400
HPU
FPU
97.9
48.3
9.7
378
427
a Weight losses of HPU and FPU at 300oC , 400 oC, and 500 oC.
b10% and 50% weight temperature, and the maximum degradation
temperature.
The thermal degradation of polyurethane is characterized by the
decomposition of urethane bonds, the degradation of soft segments,
and the evolution of the volatile components.42Fig.9 displays the
TGA and DTG curves of FPU and HPU. Obviously, the DTG curves
6 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

Page 7 of 11
Journal Name
New Journal of Chemistry
View Article Online
ARTICLE
DOI: 10.1039/C5NJ01772F
exhibit two degradation stages. The first degradation stage appearing
in the temperature from 300 to 400 oC can be attributed to the
decomposition of urethane bonds. The second degradation stage
associated with the dissociation of the soft segments occurs from 400
to 500 oC.43, 44And also, the characteristic thermal decomposition
temperature of HPU and FPUs are shown in Table 3. All the T10, T50,
Thard max and Tsoft max of FPU are higher than those of HPU and reach
340, 398, 378 and 427oC, respectively. Meanwhile, the char yield of
FPU (6.23 %) is higher than that of HPU (2.43 %). It can be
concluded that FPU has a better thermal stability than HPU,
although FPU and HPU have the same type of hard segments and
chain extender.
Surface properties of FPU and HPU
50000
45000
HPU
40000
35000
30000
25000
20000
15000
10000
5000
F1S
O1S
C1S
FPU
N1S
0
Corrosion resistance of FPU and HPU
1000
800
600
400
200
0
Binding Energy (eV)
Fig.11 The XPS survey spectra of HPU and FPU
Fig. 12 Shape of water drop on HPU(a) and FPU(b)
Table 4 Contact angle and surface energy of HPU and FPU
F% in bulk
(mol%)
F% in surfac
（mol%）
0
Contact angle Surfaceenergy
Sample
(°)
(mN/m)
36.18
Fig.10 SEM for HPU and FPU corroded by immersion in 40 wt%
NaOH and for H2SO4 24 h at room temperature: (FPUꢀa),original
FPU sample; (HPUꢀa') original HPU sample; (FPUꢀb) and (HPUꢀ
b'), FPUs and HPU corroded in 40 wt% NaOH for 24h,
respectively; (FPUꢀc)and (HPUꢀc'), FPUs and HPU corroded in
40 wt% H2SO4for 24h, respectively.
HPU
FPU
0
78.3
12.18
14.48
104.1
21.02
The surface properties of FPU and HPU were studied by XPS
and contact angles. To study the surface compositions and the
structure of HPU and FPU, the XPS analysis has been carried out.
The XPS spectra of HPU and FPU were shown in Fig.11. Compared
with HPU, the photoionization peaks of carbon, oxygen, nitrogen
and fluorine were observed in the FPU survey spectra. The bulk
fluorine molar percent and surface fluorine molar percent were listed
in Table 4. It can be found that the surface fluorine contents were
higher than the bulk fluorine, due to the migration and enrichment of
fluorinated group. In addition, the results of contact angles and
surface energy of HPU and FPU with water drop listed in Table 4
showed that FPU had significantly higher contact angle and lower
surface energy than that of HPU. This clearly indicates that the FPU
exhibit hydrophobic and unique low surface energy as a result of
introducing the fluorinated groups into soft segment, and also the
surface tension was decreased. The variance of contact angles of
FPU and HPU with water drop can be clearly seen from Fig.12.
Corrosion resistances of FPU and HPU films were evaluated by
immersing samples in 40 wt% aqueous solution of NaOH and H2SO4
shown to mimic the high corrosive environment. After immersion in
40 wt% aqueous solution of NaOH and H2SO4at room temperature
for 24 h. The original surface of HPU film under SEM shows
grooves, whereas almost no grooves are observed on FPU films (Fig.
10(FPUꢀa, HPUꢀa')), suggesting that the introduction of F into HPU
soft segments strengthens the interactions between soft and hard
segments, thus reducing the degree of microphase separation. A
comparison between HPU and FPU exposed to 40 wt% NaOH and
H2SO4 is show in Fig.10(FPUꢀb, c HPUꢀb',c'), it can be seen that
HPU shows signs of deep, aggressive corrosion after immersion in
40 wt% NaOH and H2SO4, but FPU is devoid of significant surface
corrosion. These analyses confirm that the introduction of fluorine
enhances corrosion resistance of polyurethane film.
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 7

New Journal of Chemistry
Page 8 of 11
View Article Online
ARTICLE
Journal Name
DOI: 10.1039/C5NJ01772F
The analysis of the curing kinetics of HPU and FPU
FPU:R′=ꢀCH2ꢀCF2ꢀCF2H
HPU:R′=ꢀCH2ꢀCH2ꢀCH3
54.59815
Absorbance FTIR spectra was registered to measure the
conversion of the NCO at ts. The ratio between the absorbances at
2270 cm–1 and the reference (constant) band at 1530 cm–1 was
considered in order to evaluate the conversion of NCO content at ts.
Because the absorbance at 1530 cmꢀ1 was the stretching vibrations of
the benzene ring, did not overlap with other peaks and thus provided
20.08554
50oCG'
50oCG''
60oCG'
a
direct means of monitoring the NCO concentration. The
conversion of the NCO at ts obtained from the FTIR spectra (аIR)
was calculated according to the following equation 47
60oCG''
7.38906
70oCG'
70oCG''
80oCG'
80oCG''
90oCG'
:
90oCG''
(a)
ꢅꢆꢇꢈ.ꢉ ꢄ.ꢈ
ꢅ
-2 -1
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14
ꢀꢃꢄ = 1 −
t (min)
ꢅꢆꢇꢈ.ꢈ ꢄ.ꢉ
ꢅ
Where INCO.O and IR.O are the initial peak intensities of the NCO and
reference bands, respectively, and INCO.G and IR.G are the peak
intensities of the same bands at ts. We experimented at least six
times and took the average. The results are listed at Table 5. It can be
seen that the conversions of HPU and FPU at ts are almost constant.
The average value of the FPU conversion at the ts is 48.46%. The
value of FPU is slightly higher than the HPU value of 36.02%, and
the difference is due to the higher rate of curing reaction of FPU.
Under the kinetically controlled conditions, the reaction rate
54.59815
20.08554
7.38906
2.71828
o
50 C G''
o
0
.5
0
0
.5
5
0.60
50 C G'
o
60 C G'
o
60 C G''
o
70 C G'
can be expressed by an Arrhenius rate expression as follows48ꢀ50
:
o
70 C G''
o
80 C G'
o
80 C G''
o
90 C G'
ꢊꢋ = ꢌ exp(− ꢄꢍꢎ)ꢏ(ꢐ) (1)
11
(b)
o
90 C G''
ꢊꢁ
-1
0
1
2
3
4
5
6
7
8
9
10
t (min)
Where ꢐ is the conversion, A is a constant factor, E is the activation
energy, T is the curing temperature, andꢏ(ꢐ)is the conversionꢀ
dependent function, independent of the curing temperature. By
Fig.13 Solidification point measurement of HPU(a)and FPU(b)
Table 5 The ts and conversion at tsof FPU andHPU
integrating from ꢐ=0 to ꢐ=ꢐꢁ , the equation becomes
ꢂ
HPU
FPU
Temperature
(oC)
ꢍ
ꢋꢖ ꢊꢋ
ꢂ
lnꢑ = ꢄꢎ + ꢒln ꢓ
)ꢘ − lnꢌꢙ (2)
ꢔ
ꢗ
(
ꢕ ꢋ
ꢀꢁ (%)
ꢀꢁ (%)
ts(min)
14.07
7.76
ts(min)
8.08
4.05
2.46
0.77
0.51
ꢂ
ꢂ
Since the terms in the last part of right side of equation are
constant for a fixed conversion, the equation becomes
50
60
70
80
90
35.8
36.9
34.8
36.9
35.7
47.9
48.1
48.7
49.0
48.6
4.14
ꢍ
lnꢑ = ꢚ + ꢄꢎ
(3)
1.35
0.92
Fig. 14 shows the Arrhenius plot of ln tSversus 1/T for HPU and
FPU. The apparent activation energy Ecan be calculatedfrom the
slope The activation energy E and the constant C can be determined
from the slope and the intercept of the linear relationship between ln
t vs. 1/T. The results were listed in table 6. It can be found that linear
correlations coefficient were up to 0.988 and 0.955 ,which indicates
the validity of this method. We obtained the activation energy of
HPU is 75.51 kJ·molꢀ1. And the activation energy of FPU is
70.24kJ·molꢀ1, lower than the values of HPU, indicating that the
curing reaction of FPU is much easier than that of HPU, which is in
accordance with the analysis of the ts.
The curing reaction of HPU and FPU was studied through
solidification point measurements at various temperatures, as shown
in Fig. 13.The crossovers points of G' and G'' are defined as the
solidification point (ts) 45,46. ts of FPU and HPU is the temperature in
which FPU and HPU have no fluid properties. It can be seen that the
ts decrease with the rise of temperature, it might be attributed that the
increase of temperature speeds up the reaction rate, leading to a
faster consumption of NCO. A comparison between the ts of HPU
and FPU at the same temperature is listed in Table.5. It can be seen
that the reaction process is directly related to the initial monomer
structure. When using fluorinated polyether as soft segment, the ts is
slightly shorter. These phenomena are concerned in the reactivity of
the hydroxyl in polyether. The higher electronegativity of fluorine in
FPO strongly influences the charge distribution of the hydroxyl, and
corresponding, increases the reactivity of the hydroxyl, leading to
the increase of the rate of curing reaction and reduction in the ts
apparently. The reaction mechanism of urethane formation is as flow：
8 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

Page 9 of 11
Journal Name
New Journal of Chemistry
View ArticAle ROnTliInCeLE
DOI: 10.1039/C5NJ01772F
3.0
2.5
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
Table 7 Element percentage onSꢀFPU surface
HPU
suface element molar percent (mol%)
Temperature
(oC)
C
O
N
F
FPU
70
46.81
52.24
52.44
34.23
34.19
37.41
4.48
3.96
3.56
14.48
9.61
6.59
90
y=9082.60x-25.145
110
Conclusions
y=8447.95x-24.0
A novel fluorinated polyurethane (FPU) featuring fluorineꢀ
containing side chains was successfully synthesized by
fluorinated polyether glycol with fluorineꢀcontaining side
chains as soft segments, MDI as hard segments and 1,4ꢀ
butanldiol (BDO) as chain extenders. The structure of the FPU
was characterized by FTIR and NMR. SEM directly reveals
that the extent of microphase separation reduces as the
introduction of fluorinate into the soft segment. Moreover, the
reduction of the microphase separation between the soft and
hard segments decreases the crystallinity of FPU, and increases
the Tg of soft segments and decreases the Tg of hard segment.
Meanwhile the thermal stability, surface property and corrosion
resistance of FPU have been significantly enhanced.
Furthermore, the results of the curing kinetics showed that the
introduction of F into polyurethane increased the curing rate,
and Ea of FPU (70.24 kJ·molꢀ1) is lower than that of HPU
(75.51 kJ·molꢀ1). XPS analytical result showed that there was
an obvious effect of the curing process on the mobility of
fluorinated groups to the surface of FPU.
0.00270 0.00275 0.00280 0.00285 0.00290 0.00295 0.00300 0.00305 0.00310
1/T
Fig.14 Plots of lnts versus 1/T of HPU and FPU
Table 6 Activation energy of FPU and HPU
The linear correlation
coefficient
0.988
the slope of
the lines
8447.95
conversion C
Ea
Saple
(kJ/mol)
70.24
FPU
HPU
ꢀ25.15
ꢀ24.0
0.956
9082.60
75.51
60000
55000
50000
45000
40000
35000
30000
25000
20000
15000
10000
5000
70o
90o
110o
C
C
C
F1s
O1s
Acknowledgements
C1s
N1s
This project was supported by Natural Science Foundation of
China (NO.3212310008), the innovation project of the shanghai
Municipal Education Commission(No.15ZZ076) and the
Hujiang Foundation of China(B14006).
0
1000
800
600
400
200
0
Binding Energy(eV)
Notes and references
aSchool of Materials Science and Engineering, East China University of
Fig.15 XPS survey spectra of FPU
Science and Technology, Shanghai 200237, China.
b School of Materials Science and Engineering, University of Shanghai
for Science and Technology, Shanghai 200093, China.
cDepartment ofPolymer Chemistry and Physics, Shanghai Normal
University, Shanghai 200234, China.
To sutdy the influence of curing process on the mobility of
fluorinated groups to the surface ofFPU, the XPS analysis of FPU
was carried out.The XPS survey spectra is shown in Fig. 15. The
XPS measurements showed the photoionization peaks of carbon,
oxygen, nitrogen and fluorine in the FPU survey spectra. The peak
intensity of F1s in the surface is higher at low temperature than that
E-mail address: qzhdong@ecust.edu.cn;liying@usst.edu.cn;
at high temperature. In addition, the peak intensity of N1s was weak Fax: +86-21-64251123. Phone: +86-21-64251123
due to the lower content of hydrophilic urethane groups in the
surface layer. The surface element molar percents obtained by XPS
were list in Table 7. It can be seen that the amount of surface fluorine
increases with decreasing thecuring temperature, indicating thatthe
curing process has a great influence on the mobility of fluorinated
groups .From the result of the analysis of ts, we knew that with
increasing temperature, the tsdecreases and the curing rateincreases.
Thus, there is not enough time for fluorinated groupsto migrate to
the surface of FPU, leading to the decrease of F content in FPU
surface.Thus it can be concluded that to select the appropriate curing
temperature is propitious for the movement of fluorinated group and
flurorinesurface enrichment.
1 D. K. Chattopadhyay, K. V. S. N. Raju. Prog. Polym. Sci., 2007, 32, 352.
2 X. L. Li, Z, Fang, X. Li, S. G. Tang. K. Zhang. New J. Chem., 2014, 38,
3874.
3 Z. Y. Lan，R. Daga, R. Whitehouse, S. McCarthy, D, Schmidt. Polymer.
2014, 55, 2635.
4 W. J. Lee, M, S, Lin. J. Appl. Polym. Sci., 2008, 109, 23.
5 M. Y. L Chew, X. Zhou, Y, M, Tay. Poly. Test., 2001, 28, 87.
6 P. Krol. Prog. Mater. Sci., 2007, 52, 915.
7 C. B. McCloskey, C. M. Yip, J. P. Santerre. Macromolecules, 2002, 35, 924.
8.Z. Ge, X. Y. Zheng, J. B. Dai, W. H. Li, Y. J. Luo. Eur. Polym. J., 2009, 45,
530.
9 C. Wang, X. R. Li, B. Du, P.Z. Li. Colloid. Polym Sci., 2014, 292, 579.
10 M. Zhang, S.L.Zhou, J.Univ. Shanghai. Sci. Technol.,1998,3,272.
11 S. Turri,M. Levi,T. Trombetta,J. Appl. Polym. Sci.,2004,93, 136.
12 S, Turri, M. Levi, T. P. Trombetta,Macromol. Symp.,2004,218, 29.
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 9

New Journal of Chemistry
Page 10 of 11
View Article Online
ARTICLE
Journal Name
DOI: 10.1039/C5NJ01772F
13 Y. S. Kim, J. S. Lee,Q. Ji,J. E. McGrath,Polymer,2002,43, 7161.
14 V. Durrieu,A.Gandini, Polym. Adv. Tech., 2005,16, 840.
15 M. J. Zhu,F. L. Qing,W. D. Meng,J. Appl. Polym. Sci.,2008,109, 1911.
16 C. H. Lim, H. S.Choi, S. T. Noh.J. Appl. Polym. Sci., 2002, 86, 3322.
17 Z. Ge, X. Y. Zhang, J. N. Dai. J.Macromol. Sci. PartA: Pure Appl.
Chem.,2009, 46, 215.
18 C.Tonelli, G. J. Ajroldi, J. Appl. Polym. Sci.,2003, 87, 2279.
19 S. C. Yoon, B. D. Ratner. Macromolecules, 1988, 21, 2392.
20 S. C. Yoon, B. D. Ratner. Macromolecules, 1988, 21, 2401.
21 P. F Liu, L. Ye, Y. G. Liu, F. D. Nie. Polym. Bull., 2011, 66, 503.
22 M. Castellano, C.Tonelli, A. Turturro. J Mater Sci.,2014, 49, 2519.
23 T. Liu, L. Ye, J. Fluorine Chem., 2010, 131, 36.
24 R. P. Jia, A, X, Zong, X. Y. He, J. Y. Xu, M. S. Huang, Fiber. Polym.,
2015, 16, 231.
25 G. Marchionni, G, Ajroldi, M. C. Righetti, G. Pezzin. Macromolecules,
1993, 27, 1751.
26 A. Milani, J. Zanetti, C. Castiglioni, E. D. Dedda, S. Radice. Eur. Poly. J,
2012, 48, 391.
27 L. Mashlyakovskiy, V. Zaiviy, G. Simeone, C. Tonelli,J. Polym. Sci.: Part
A: Polym. Chem.,1999, 37, 557.
28 S. Turri, T. Trombetta, M. Levi,Macromol. Mater. Eng. 2000, 283, 144.
29 L. L. Li, Y. Li, X. Wang, Q. Z. Dong, Emerg. Mater. Res., 2015, 4, 102.
30 L. L. Li, Y. Li, X. Wang, Y. C. Qing, J. J. Hu, J. Fluorine Chem.,2015, 175,
129.
31R.M.Romano, J.Czarnowski, C. O. D.Vedova,Inorg.Chem., 2001, 40,
3039.
32 M. E.Ryan,J. L. C. Fonseca, S.Tasker,J. P. S. Badyal,J. Phys. Chem.,1995,
99, 7060.
33Y. J.Xu,Z.Petrovic, S.Das,G. L.Wilkes, Polymer,2008, 49, 4248.
34 L. F.Wang, Polymer, 2007, 48, 894.
35 W. W. Yu, M.Du, D. Z.Zhang,L.Yu, Q.Zheng, Macromolecules,2013, 46,
7341.
36 A. M. Castagna, A. Pangon，T. Choi，G. P. Dillon,Macromolecules,
2012, 45, 8438.
37 C. Tonelli, G. Ajroldi, A. Turturro, A. Marigo, Polymer, 2001, 42, 5589.
38 H. Tan, J. H. Li, R. G. Du. Polymer, 2005, 46, 7230.
39 Y. J. Xu, Z. Petrovic, S. Das, G. L. Wilkes, Polymer, 2008, 49, 4248.
40 C. B. Wang, S. L. Cooper.Macromolecules, 1983,16,775.
41 P. F. Liu. L. Ye. Y. G. Liu, F. D. Nie, Polym. Bull.,2011, 66, 503.
42 Y. J. Xu, Z. Petrovic, S. Das, Polymer,2008,49,4248.
43 M. G. Lu, J. Y.Lee, M. J.Shim, S. W.Kim, J. Appl. Polym. Sci., 2002, 85,
2552.
44 H. Q. Fu, C. B. Yan, W. Zhou, H. Huang,Comp. Sci. Tech.,2013, 85, 65.
45 Xu Weibing, He Pingsheng, Chen Dazhu. Eur. Polym. J., 2003,39, 617..
46 Tung, C. Y. M., Dynes, P. J., J. Appl. Polym. Sci.,1982, 27, 569ꢀ574.
48 D. Olmos, A. Loayza, J. GonzálezꢀBentito. J. Appl. Polym. Sci., 2010,
117, 2695.
49 R. Rodriguez, B. Perez, J. Adhes., 2014, 90, 848.
50 L. Nu
́n ̃ez, J. Taboada, F. Fraga, M.R. Nu ń ̃ez, J. Appl. Polym. Sci., 1997,
66, 1377.
51 S. Cho, E. P. Douglas, J. Y. Lee, Polym. Eng. Sci., 2006, 46, 623.
.
10 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

Page 11 of 11
New Journal of Chemistry
View Article Online
DOI: 10.1039/C5NJ01772F
For the Table of Contents Entry
The synthesis and curing kinetics study of a new fluorinated
polyurethane with fluorinated side chains attached to soft blocks
Lingling Li, Xia Wang*, Zan Li , Ying Li* , Yuanchun Qi , Qingzhi Dong*
Fluorinated polyurethane with fluorinated side chains attached to soft blocks was successfully
synthesized, which exhibited unique properties. And also the curing kinetics was studied using
rotational rheometer.