Facile synthesis of high-performance poly(pyrrolone imide)s from an unsymmetric phosphinated triamine

Article abstract of DOI:10.1002/pola.26666

High-performance and flexible poly(pyrrolone imide)s (PPyIs) were firstly prepared by the reaction of dianhydrides with an unsymmetric phosphinated triamine, 1-(3,4-diaminophenyl)-1-(4-aminophenyl)-1-(6-oxido-6H -dibenz <1,2> oxaphosphorin-6-yl)ethane (1), which was prepared by a facile, one-pot procedure from the reaction DOPO, 4-aminoacetophenone in excess o-phenylenediamine in the presence of p-toluenesulfonic acid. Thermal properties of the resulting PPyIs were evaluated and compared with those of phosphinated polyimides with a similar structure. All of the prepared PPyIs films are tough and creasable. They display higher T_g (374-412 °C), lower coefficient of thermal expansion (34-46 ppm/°C), and better thermal stability (T_d 5 wt %: 456-477 °C, 800 °C char yield: 59-63%) than analogous phosphinated polyimides.

Full text of DOI:10.1002/pola.26666

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Facile Synthesis of High-Performance Poly(pyrrolone imide)s from an
Unsymmetric Phosphinated Triamine
Ching Hsuan Lin,1 Chen Ming Li,1 Chin Kuang Hsu,1 Hou Chien Chang,1 Tzong Yuan Juang2
1Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan
2Department of Applied Chemistry, National Chiayi University, Chiayi, Taiwan
Correspondence to: C. H. Lin (E-mail: linch@dragon.nchu.edu.tw) or H. C. Chang (E-mail: hchang@dragon.nchu.edu.tw)
Received 4 January 2013; accepted 7 March 2013; published online 2 April 2013
DOI: 10.1002/pola.26666
ABSTRACT: High-performance and flexible poly(pyrrolone
imide)s (PPyIs) were firstly prepared by the reaction of dianhy-
drides with an unsymmetric phosphinated triamine, 1-(3,4-dia-
minophenyl)-1-(4-aminophenyl)-1-(6-oxido-6H -dibenz <c,e>
<1,2> oxaphosphorin-6-yl)ethane (1), which was prepared by a
facile, one-pot procedure from the reaction DOPO, 4-aminoace-
tophenone in excess o-phenylenediamine in the presence of
p-toluenesulfonic acid. Thermal properties of the resulting PPyIs
were evaluated and compared with those of phosphinated polyi-
mides with a similar structure. All of the prepared PPyIs films are
tough and creasable. They display higher Tg (374–412 ꢀC), lower
coefficient of thermal expansion (34–46 ppm/ꢀC), and better ther-
mal stability (Td 5 wt %: 456–477 ꢀC, 800 ꢀC char yield: 59–63%)
C
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than analogous phosphinated polyimides. 2013 Wiley Periodi-
cals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2709–2715
KEYWORDS: functionalization of polymers; polyimides; thermal
properties; toughness
3,30,4,40-tetraamine biphenyl hexafluoroisopropylidene were
successfully prepared from bisphenol A and hexafluoro
bisphenol A, respectively. Vora et al.5 prepared 3,30,4,40-tetra-
amine biphenyl hexafluoroisopropylidene by a different strat-
egy using aminophenol hexafluoropropane as the starting
material. PPy based on hexafluoroisopropylidene-bisphthalic
anhydride (6FDA) and 3,30,4,40-tetraamine hexafluoroisophe-
nylene biphenyl showed attractive transport properties, high
permeability and good selectivity. Another limitation for the
development of PPys is their poor solubility in organic sol-
vents. PPys resulting from ester-,6 amide-,7 and ether-con-
taining dianhydrides8 with aromatic tetraamines have been
developed to improve their solubility and flexibility. Zhang
and coworkers9 prepared tetraamines with flexible ether
INTRODUCTION Polypyrrolones (PPys) are one of the most
important semiladder heteroaromatic polymers. They were
first synthesized by the reaction of dianhydride and aromatic
tetraamine in 1965.1 The reaction involves the formation of
poly(amide amino acid), followed by thermal cyclization.
Because of the multiaromatic structure of imide and imidaz-
ole, PPys exhibit excellent properties such as high-glass tran-
sition temperature, high-temperature stability, chemical
resistance, and good fluid separation properties.2 Xuesong
and Fengcai3 compared the gas transport properties of PPys
and polyimides with a structure similarity, and found that
PPys exhibit higher permeability and selectivity than analo-
gous polyimides do. The much higher rigidity of the back-
bone of PPys inhibits chain packing, which results in
increased permeability, while the suppression of chain seg-
mental motion in the PPys leads to greater selectivity. How-
ever, commercially available tetraamines are generally
limited to 1,2,4,5-tetraaminobenzene, 3,30,4,40-tetraamine
biphenyl, and 3,30,4,40-tetraamine diphenyl ether, restricting
the development of PPys. Therefore, preparation of new tet-
raamine is crucial in the development of PPys. Koros and
linkages by
a
two-step procedure from bisphenols
using nucleophilic substitution of bisphenol with 5-chloro-2-
nitroaniline, followed by a reduction in the nitro groups.
Organo-soluble poly(bis(benzimidazobenzisoquinolinones))
are prepared from the diether tetraamines and bis(naph-
thalic anhydrides). Yang and coworkers10 prepared pyridine-
bridge tetraamines with a bulky pendant to improve the
solubility of the PPys. Previously, we also prepared organo-
soluble phosphinated polyimides from asymmetric diamine
with excellent mechanism, high-Tg and flame-retardant
properties.11
Walker4 prepared bisphenol-based tetraamines using
a
three-step procedure that included nitration of bisphenols,
nucleophilic exchange, and reduction. Through this approach,
tetraamines, 3,30,4,40-tetraamine biphenyl isopropylidene and
Additional Supporting Information may be found in the online version of this article.
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Incorporating imide linkage into PPys is a strategy to
enhance the solubility and toughness without sacrificing too
much in the thermal properties. Bell prepared poly(pyrro-
lone imides)s (PPyIs) for potential use in aerospace by
copolymerizing tetraamine/diamine and dianhydride to
increase the toughness of PPys.12 Yang coworkers prepared
thermosetting PMR type PPyIs by copolymerizing tetra-
amine/diamine, diester of diphthalic acid, and monoester of
dicarboxylic acid.13 Burns and Koros prepared PPyIs by
copolymerizing tetraamine/diamine and dianhydride to con-
trol the permeability and selectivity.14 Generally, PPyIs are
prepared by the copolymerization of diamine and tetraamine
with dianhydrides. To the best of our knowledge,
PPyIs based on an unsymmetric triamine have not been
reported. Herein, with our continuing effort to prepare
high-performance polymers, an aromatic triamine, 1-(3,4-dia-
minophenyl)-1-(4-aminophenyl)-1-(6-oxido-6H-dibenz <c,e>
<1,2> oxaphosphorin-6-yl)ethane (1) was prepared. Based
on the polycondensation of triamine (1) and dianhydrides, a
series of poly(pyrrolone imide)s (PPyIs) (2a–2d) were pre-
pared. We found that all the prepared PPyI films are tough
and creasable, and display better thermal properties than
analogous polyimides. Herein, the detailed synthesis and
characterization of the triamine (1) are reported. The ther-
mal properties of PPyIs are also reported and compared
with those of analogous polyimides.15
Pyris Diamond DMA with a sample size of 5.0 3 1.0 3 0.2
cm3. The storage modulus E0 and tan d were determined as
the sample was subjected to a temperature scan mode at a
programmed heating rate of 5 ꢀC/min at a frequency of 1
Hz. The test was performed by a bending mode with ampli-
tude of 5 lm. Thermal mechanical analysis (TMA) was per-
formed by a SII TMA/SS6100 at a heating rate of 5 ꢀC/min.
Thermal gravimetric analysis (TGA) was performed with a
Perkin-Elmer Pyris1 at a heating rate of 20 ꢀC/min in an
atmosphere of nitrogen or air. The flame retardancy of polyi-
mides was performed by a UL-94VTM vertical thin test. In
that test, an 800 3 200 sample was wrapped around a 1/200
mandrel, and then taped on one end. The mandrel was
removed, leaving a cone-shaped sample that was relatively
rigid. The two flame applications took 3 s each for the UL-94
VTM vertical thin film. After the first ignition, the flame was
removed and the time for the polymer to self-extinguish (t1)
was recorded. Cotton ignition was noted if polymer dripping
occurred during the test. After cooling, the second ignition
was performed on the same sample and the self-extinguish-
ing time (t2) and dripping characteristics were recorded. If
t1 plus t2 was less than 10 s without any dripping, the poly-
mer was considered to be a VTM-0 material. If t1 plust2 was
in the range of 10–30 s without any dripping, the polymer
was considered to be a VTM-1 material.
Synthesis of (1)
EXPERIMENTAL
DOPO 5.00 g (21.7 mmol), 4-aminoacetophenone 2.94 g
(21.7 mmol), p-TSA 0.20 g (4 wt % based on the weight of
DOPO), and o-phenylenediamine 11.70 g (108.5 mmol, five-
fold equivalents) were introduced into a 250-mL round bot-
tom glass flask equipped with a nitrogen inlet and a mag-
Materials
9,10-Dihydro-oxa-10-phosphaphenanthrene-10-oxide (DOPO,
TCI), 4-aminoacetophenone (from Acros), o-phenylenedi-
amine (from Acros), and p-toluenesulfonic acid monohydrate
(p-TSA, from SHOWA) were used as received. Pyromellitic
dianhydride (PMDA, from Acros) was dried at 170 ꢀC over-
night before use. 3,30,4,40-Benzophenonetetracarboxylic dia-
nhydride (BTDA, from Acros), 4,40-oxydiphthalic anhydride
(ODPA, from Chriskev), and 3,30,4,40-biphenyltetracarboxylic
dianhydride (BPDA, from Chriskev) were recrystallized from
acetic anhydride. N,N-dimethylacetamide (DMAc) was pur-
chased from TEDIA and purified by distillation under
reduced pressure over calcium hydride (from Acros) and
stored over molecular sieves. The other solvents used are
commercial products (HPLC grade) and used without further
purification.
ꢀ
netic stirrer. The mixture was stirred at 130 C for 24 h. The
precipitate was filtered and washed with ethanol. Purple
powder (71% yield) 1-(3,4-diaminophenyl)-1-(4-amino-
phenyl)-1-(6-oxido-6H -dibenz <c,e> <1,2> oxaphosphorin-
6-yl)ethane (1) with a sharp melting point at 238 ꢀC (by
DSC) was obtained. Elem. Anal. for C26H24N3O2P: Calcd. C
70.74%, H 5.48%, N 9.52%; Found C 70.60%, H 5.55%, N
9.46%
1H NMR (ppm, DMSO-d6), d 5 1.45 (3H, H6), 4.39 (4H, NH2),
5.01 (2H, NH2), 6.37 (2H, H2), 6.41 (2H, H21), 6.62 (1H, H20),
6.69 (1H, H24), 6.92 (2H, H3), 7.00 (1H, H11), 7.19 (1H, H15),
7.22 (1H, H17), 7.37 (1H, H16), 7.63 (1H, H9), 8.01 (1H, H14),
8.08 (1H, H8). 13C NMR (ppm, DMSO-d6), d 5 24.21 (C14), 51.83
(C13), 112.95 (C22), 113.84 (C17), 114.87 (C20), 117.51 (C16),
119.15 (C8), 121.08 (C11), 123.22 (C10), 123.33 (C1), 123.84
(C6), 125.34 (C5), 125.65 (C12), 127.57 (C3), 130.32 (C23),
130.52 (C7), 132.05 (C4), 132.10 (C15), 132.97 (C2), 133.51
(C24), 134.51 (C18), 135.86 (C19), 147.38 (C21), 150.78 (C9).
Characterization
NMR measurements were performed using a Varian Inova
600 NMR in DMSO-d6, and the chemical shift was calibrated
by setting the chemical shift of DMSO-d6 at 2.49 ppm. The
assignment of individual peak of (1) is assisted by the corre-
lations shown in the 1H-1H COSY and 1H-13C HETCOR NMR
spectra. IR Spectra were obtained in the standard wavenum-
ber range of 500–3650 cm21 by Perkin-Elmer RX1 infrared
spectrophotometer. Differential scanning calorimeter (DSC)
scans were obtained by a Perkin-Elmer DSC 7 in a nitrogen
atmosphere at a heating rate of 20 ꢀC/min. Dynamic me-
chanical analysis (DMA) was performed with a Perkin–Elmer
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SCHEME 1 Synthesis of triamine (1).
FIGURE 1 (a) 1H and (b)13C NMR spectra of triamine (1).
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SCHEME 2 Synthesis of PPyIs 2 and referenced polyimides 20.
the 1H-1H COSY spectrum (Supporting Information Fig. S1),
confirms the structure of (1). In the 13C NMR spectrum, due
to the P-C 1J coupling, the C13 signals were split into two
peaks at 51.1 and 51.7 ppm with a coupling constant of 92
Hz. The C10 signals were also split into two peaks at 122.6
and 123.4 ppm with a coupling constant of 111.0 Hz for the
same reason. The Ar-C peaks, assigned by the correlations in
the 1H-13C HETCOR spectrum (Supporting Information Fig.
S2), were detailed in Figure 1(b), also confirming the struc-
ture of (1). In the 31P NMR spectrum, only one 31P NMR
peak at 40.4 ppm was observed, indicating the intactness of
the biphenylene phosphinate pendant during preparation.
Preparation of PPyIs
PPyIs were prepared by reacting (1) with an equal mole of
dianhydrides (a–d). The synthesis of PPyIs is exemplified by
specific synthesis of 2b from the condensation of (1) and
ODPA. The other PPyIs were similarly prepared. (1) 0.4415
g (1.000 mmol), two drops of isoquinoline, and m-cresol 15
mL were added into a 100-mL three-neck round-bottom
flask equipped with a magnetic stirrer and nitrogen inlet. Af-
ter (1) had dissolved completely, ODPA 0.3102 g (1.000
mmole) was quickly added and the mixture was reacted at
reflux temperature for 12 h. The viscous solution was then
cast on glass using an automatic film applicator, and dried at
80 ꢀC overnight and imidized at 100 ꢀC (1 h), 200 ꢀC (1 h)
ꢀ
and 300 C (1 h), respectively.
RESULTS AND DISCUSSION
Synthesis of (1)
In this work, triamine (1) was facilely prepared by the reac-
tion of DOPO, 4-aminoacetophenone and o-phenylenediamine
using p-TSAS as the catalyst (Scheme 1). The excess o-phen-
ylenediamine (fivefold equivalent) plays the roles of both a
reactant and the reaction medium. The only byproduct is
water, so the atom efficiency of this reaction is relatively
high.
Figure 1 shows the (a) 1H and (b) 13C NMR spectra of (1).
1
In the H NMR spectrum, two amino peaks at 5.0 (C21ANH2)
and 4.4 (C18ANH2 and C19ANH2) ppm were observed. The
resonance between the ortho amino groups upshifted the
chemical shift 4.4 ppm. Methyl peaks at around 1.5 ppm
were observed. The methyl signals were split into two peaks
3
with a coupling constant of 17.4 Hz because of a JP-H cou-
pling. The assignment of Ar-H, assisted by the correlations in
FIGURE 2 IR spectra of 2b, 2b0, and (1).
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FIGURE 3 DMA thermograms of PPyIs 2.
Referring to the reaction mechanism reported by Choi and
17
coworker16 and Kray and Rosser
a reaction mechanism
was proposed for the preparation of (1) in Supporting In-
formation Scheme S1. In Supporting Information Scheme
S1, DOPO attacks the carbonyl group of 4-aminobenzophe-
none via a nucleophilic addition, forming an intermediate
with a tertiary hydroxyl group. The tertiary hydroxyl group
is then protonated by the acid. Spontaneous dissociation of
the protonated hydroxyl group occurs to yield a tertiary
carbocation. The o-phenylenediamine then reacts with the
resulting carbocation via an electrophilic substitution,
yielding (1).
FIGURE 5 TGA thermograms of 2 in the atmosphere of (a)
nitrogen and (b) air.
(imide ring deformation) support the imide structure of 2b.
In particular, a C@N absorption at 1670 cm21, which is not
observed in 2b0, supports the structure of pyrrolone. As
shown in Figure 2, the amino absorptions of (1) are located
at 3350 and 3420 cm21. However, no obvious amino absorp-
tions were observed in 2b, supporting the cyclization of im-
ide and pyrrolone.
Polymer Synthesis
PPyIs (2a-2d) were prepared by reacting (1) with various
commercially available dianhydrides (a–d) in m-cresol
through high temperature solution polymerization (Scheme
2). The yield is quantitative. Figure 2 shows the IR spectra
of 2b, the referenced polyimide 2b0, and (1). The absorp-
tions of C@O asymmetric and symmetric stretches at 1783
and 1725 cm21 were clearly observed for 2b. The absorp-
tions at 1371 cm21 (CAN Stretch), 1116 and 723 cm21
Film Quality and Thermal Properties
As all of the PPyI films are tough and creasable, DMA and
TMA were applied to evaluate their thermal mechanical
properties and dimensional stability. No GPC data were avail-
able since the films are insoluble in THF. However, all the
films are tough and creasable, so the molecular weights are
thought to be relatively high. Figure 3 shows the DMA ther-
mograms of the PPyIs 2. The value of Tg obtained from the
peak temperature of tan(delta) is as high as 412, 374, 388,
and 393 ꢀC for 2a–2d, respectively. Among the PPyIs, 2a
shows the highest Tg value due to the rigid pyromellitic moi-
eties. In contrast, 2b displays the lowest Tg value because of
the flexible ether linkage. Except for 2a, the Tg values of
PPyIs 2 are 50–60 ꢀC higher than those of analogous polyi-
mides,15 demonstrating the high-Tg characteristic of the pyr-
rolone linkage.
Figure 4 shows the TMA curves of PPyIs 2. The Tg values
measured by TMA are in the range of 378–304 ꢀC, which is
slightly lower than those measured by DMA. CTE at 100–250
ꢀC are in the range of 34–46 ppm/ꢀC. The CTE values are
FIGURE 4 TMA curves of PPyIs 2.
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TABLE 1 Thermal Properties of PPyIs (2) and Ref PI (20)
Td5%
Char Yieldf
N2 Air
e
Sample Code
Film Quality
E0 (GPa)a
Tg (ꢀC)b
Tg (ꢀC)c
CTEd
N2
Air
2a
creasable
creasable
creasable
creasable
creasable
creasable
creasable
creasable
2.82
2.82
1.82
3.58
4.49
4.44
3.39
4.69
412
374
388
393
392
318
326
343
378
345
355
361
388
304
312
330
34
46
43
38
42
48
50
43
477
456
474
462
435
439
426
437
477
447
452
454
448
447
439
439
63
62
60
59
57
51
55
50
63
50
60
54
34
21
21
20
2b
2c
2d
2a’
2b’
2c’
2d’
a
d
e
Measured by DMA at a heating rate of 5 ꢀC/min; storage modulus (E0)
Coefficient of thermal expansion are recorded from 100 to 250 ꢀC.
are recorded at 50 ꢀC.
b
Temperature corresponding to 5% weight loss by thermogravimetry at
Peak temperature of tan(d) in the DMA thermogram.
Measured by TMA at a heating rate of 5 ꢀC/min.
a heating rate of 20 ꢀC/min in the atmosphere of nitrogen or air.
f
c
Residual weight % at 800 ꢀC in the atmosphere of nitrogen or air.
smaller than those of the analogous polyimides, displaying
the dimensional stability of the pyrrolone linkage is better
than that of the imide linkage.
PPyIs is comparable with the analogous phosphinated polyi-
mides 20. In contrast, the t1 1 t2 took more than 6 s for Kap-
ton. Although Kapton also belongs to the VTM-0 grade, the
shorter total burning time of PPyIs 2 demonstrates the
excellent flame retardancy provided by the phosphorus
element.
Thermal Stability and Flame Retardancy
The thermal stability of the PPyIs was evaluated by TGA in
an atmosphere of (a) nitrogen and (b) air (Fig. 5 and Table
1). The 5 wt % degradation temperatures of the PPyIs 2
range from 477 to 456 ꢀC, which are approximately 30 ꢀC
higher than those of 20. Therefore, the semiladder structure
of pyrrolone that exhibits better rigidity than linear imide2,3
is thought to be responsible for the enhanced thermal stabil-
ity. The char yields in a nitrogen atmosphere are in the
range of 63–59 wt %, and are 5–10 wt % higher than those
of 20. As listed in Table 1, the difference in the char yields of
2 in nitrogen and air is smaller than that of 20. For example,
the difference in the char yield of 2b is 12 wt %, while the
value is 30 wt % for 2b0. The TGA data demonstrate the bet-
ter anti-oxidative properties of the pyrrolone linkage. The
flame retardancy of the PPyIs was measured by a UL-94VTM
vertical thin test (Table 2). The t1 1 t2 value was less than 3
s for the PPyIs. Therefore, they belong to the VTM-0 grade.
Experimental data also show that the total burning time of
CONCLUSIONS
We have revealed a one-pot process to prepare an unsym-
metric triamine (1). Based on (1), a series of phosphinated
PPyIs were prepared. Because of the unsymmetric structure
of (1) that leads to irregular pyrrolone and imide sequence,
all the PPyIs are soluble in m-cresol. Tough and creasable
films can be obtained even without the presence of flexible
linkages in the main chain. The resulting PPyIs display
higher glass transition temperature, dimensional stability
and thermal stability than the analogous polyimides do. The
combination of flexibility, high glass transition temperature,
high thermal stability, organosolubility in m-cresol, and
excellent flame retardancy makes PPyIs 2 promising high-
performance polymers.
TABLE 2 Data of UL-94 VTM test for 2, 20, and Kapton
REFERENCE AND NOTES
1 V. L. Bell, G. F. Pezdirtz, J. Polym. Sci. Part B: Polym. Lett.
1965, 3, 977–984.
First
Second
Burning
Time (s)
Sample
Code
Burning
Time (s)
UL-94
Grade
2 H. Scott, F. L. Serafin, P. L. Kronick, J. Polym. Sci. Part B:
Polym. Lett. 1970, 8, 563–571.
Dripping
2a
0.9 (0.7)a
1.4 (1.5)
1.3 (1.2)
1.3 (1.0)
4.6
0.4 (0.2)
0.3 (0.3)
0.3 (0.3)
0.4 (0.3)
1.8
No
No
No
No
No
VTM-0
VTM-0
VTM-0
VTM-0
VTM-0
3 G. Xuesong, L. Fengcai, Polymer 1995, 36, 1035–1038.
4 W. J. Koros, D. R. B. Walker, US Patent 5,262,056, 1993.
2b
2c
5 R. H. Vora, C. S. N. Paul, J. D. Menczel, US Patent 5,075,419,
1991.
2d
6 D. Sek, E. Schab-Balcerzak, E. Grabiec, Polymer 1998, 39,
Kapton
7001–7008.
a
The data in the parentheses is the average burning time of
7 D. Sek, E. Schab-Balcerzak, E. Grabiec, Polymer 1999, 40,
2419–2428.
polyimide 20.
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8 D. Sek, E. Schab-Balcerzak, E. Grabiec, A. Volozhin, T. Cha-
menko, Polymer 2000, 41, 49–56.
13 Y. F. Li, A. J. Hu, X. C. Wang, S. Q. Gao, S. Y. Yang, J. Appl.
Polym. Sci. 2001, 82, 1600–1608.
9 J. Wang, N. Li, F. Zhang, S. Zhang, J. Liu, Polymer 2009, 50,
14 R. L. Burns, W. J. Koros, Macromolecules 2003, 36, 2374–
810–816.
2381.
10 J. G. Liu, L. F. Wang, H. X. Yang, H. S. Li, Y. F. Li, L. Fan, S.
Y. Yang, J. Polym. Sci. Part A: Polym. Chem. 2004, 42, 1845–
1856.
15 C. W. Chang, C. H. Lin, P. W. Cheng, H. J. Hwang, S. A. Dai,
J. Polym. Sci. Part A: Polym. Chem. 2009, 47, 2486–2499.
16 M. H. Yi, W. Huang, M. Y. Jin, K. Y. Choi, Macromolecules
1997, 30, 5606–5611.
11 C. H. Lin, S. L. Chang, L. A. Peng, S. P. Peng, Y. H. Chuang,
Polymer 2010, 51, 3899–3906.
17 W. D. Kray, R. W. Rosser, J. Org. Chem. 1977, 42, 1186–
12 V. L. Bell, J. Appl. Polym. Sci. 1970, 14, 2385–2398.
1189.
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