Synthesis and characterization of [60]fullerene-poly(3-azidomethyl-3-methyl oxetane) and its thermal decomposition

Article abstract of DOI:10.1039/c5ra16892a

A new functionalized fullerene derivative, [60]fullerene-poly(3-azidomethyl-3-methyl oxetane) (C₆₀-PAMMO), was synthesized for the first time using a modified Bingel reaction with [60]fullerene (C₆₀) and bromomalonic acid poly(3-azidomethyl-3-methyl oxetane) ester (BM-PAMMO). The product was characterized by Fourier transform infrared (FTIR), ultraviolet-visible (UV-vis), and nuclear magnetic resonance (NMR) spectroscopy analyses. The results confirmed the successful preparation of C₆₀-PAMMO. Moreover, the thermal decomposition of C₆₀-PAMMO was analyzed by differential scanning calorimetry (DSC), thermogravimetric analysis coupled with infrared spectroscopy (TG-IR), and in situ FTIR spectroscopy. The decomposition of C₆₀-PAMMO showed a three-step thermal process. The first step at approximately 150 °C was related to the cycloaddition of the azido groups (-N₃) with [60]fullerene. The second step was ascribed to the decomposition of the remaining PAMMO main chain at approximately 320 °C. The final step was attributed to the burning decomposition of amorphous carbon, the main chain, N-heterocyclic components and the carbon cage around 510 °C.

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ARTICLE
Synthesis and Characterization of [60]Fullerene-
poly(3-azidomethyl-3-methyl oxetane) and Its
Thermal Decomposition
Cite this: DOI: 10.1039/x0xx00000x
Jun Zhao,a Bo Jin,a,* Rufang Peng,a,* Nengmei Deng,a Wenlin Gong,a Qiangqiang Liu,a
Shijin Chua
Received 00th January 2012,
Accepted 00th January 2012
DOI: 10.1039/x0xx00000x
A new functionalized fullerene derivative [60]fullerene poly(3-azidomethyl-3-methyl oxetane) (C60-
PAMMO) was synthesized for the first time using a modified Bingel reaction of [60]fullerene (C60) and
bromomalonic acid poly(3-azidomethyl-3-methyl oxetane) ester (BM-PAMMO). The product was
characterized by Fourier transform infrared (FTIR), ultraviolet-visible (UV-vis), and nuclear magnetic
resonance (NMR) spectroscopy analyses. Results confirmed the successful preparation of C60-PAMMO.
Moreover, the thermal decomposition of C60-PAMMO was analyzed by differential scanning calorimetry
(DSC), thermogravimetric analysis coupled with infrared spectroscopy (TG-IR), and in situ FTIR. C60-
PAMMO decomposition showed a three-step thermal process. The first step at approximately 150 °C
was related to the cycloaddition of azido groups (-N3) with [60]fullerene. The second step was ascribed
to the remainder decomposition of the PAMMO main chain at approximately 230 °C. The final step was
attributed to the burning decomposition of amorphous carbon, the main chain, N-heterocyclic and carbon
cage at around 510 °C.
www.rsc.org/
PAMMO was further functionalized via esterification with malonyl
Introduction
dichloride and subsequent brominate reaction to afford
Given the attractive chemical and physical properties of C60,
bromomalonic acid PAMMO ester (BM-PAMMO). BM-PAMMO
studies on its application are extensive since its macroscale easily reacts with C60 through a modified Bingel reaction42 to afford
synthesis,1 which shows promising applications in medicine
an energetic fullerene derivative C60-PAMMO. The thermal
decomposition performance and decomposition mechanism of C60-
PAMMO were also examined in detail.
and material science. As C60 has good features such as thermal
stability, antioxidation, etching resistance, good compatibility
with propellant components, and beneficial for preventing
aging.2-5 Thus, C60 can replace carbon black as the solid rocket
fuel additive that can increase the burning rate and combustion
catalytic efficiency and decrease the amount of NOx in the
exhaust gas.6-11 If some energetic groups, such as nitro group (-
NO2) and azido group (-N3), were incorporated in the
[60]fullerene cage, then a better fuel additive may be
obtained.12-26
Usually, azide energetic material has higher thermal stability27-33
and the thermal decomposition of azido group was ahead of the main
chain and independent, which can help increase the energy and
accelerate the decomposition of the propellant. Poly(3-azidomethyl-
3-methyl oxetane) (PAMMO), a azido polymer, has attracted
researchers’ attention and has been used as energetic binder in
propellant and explosive formulations because of its higher positive
heat of formation, higher density, higher nitrogen content, and lower
mechanical sensitivity.34-39 Moreover, the terminal hydroxyl group
of PAMMO can be easily modified through various reactions, such
as esterification, acetalization, etherification, etc.40,41 In this paper,
Experimental section
Chemicals and Apparatus
[60]fullerene was purchased from Henan Tianan Company.
HMMO was purchased from Xiya Reagent. The 300-400 mesh
silica gel was purchased from Qingdao Hailang. All the other
chemicals were purchased from Chengdu Kelong Chemical
Reagents Company. Dichloromethane was dried on P2O5 and
redistilled under vacuum before use.
N,N-dimethylformamide
(DMF) and dimethyl sulfoxide (DMSO) were dried on
anhydrous MgSO4 and distilled under vacuum.
1H and 13C NMR spectra were recorded on a Bruker Advance
DRX 400-MHz instrument with CDCl3 as the solvent and
tetramethylsilane as the internal reference. FTIR spectra were
obtained on a Nicolet 6700 FT-IR spectrometer with a resolution of
4 cm-1 from 400 cm−1 to 4000 cm−1. UV-vis spectra were recorded
on UNICON UV-2102 PCS spectrometer with CH2Cl2 as the
solvent. Differential scanning calorimetry (DSC) curves were
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DOI: 10.1039/C5RA16892A
recorded on a SDT Q600 TGA-DSC instrument in flowing air at a
heating rate of 10 oC/min. Thermogravimetry with infrared
C aromatic ring), 1463 (δ CH2), 1360 (vas S(=O)2), 1180 (vs S(=O)2),
1096 (δs C-H aromatic ring), 977 (vas C-O-C oxetane, vas S-O-C), 837
1
spectrometry (TG-IR) was performed using
a
Q500 (vs S-O-C), 665 (ω C-H aromatic ring). H-NMR (CDCl3, 400 MHz)
δ/ppm: 7.83-7.38 (4H, m, aromatic ring), 4.39-4.35 (4H, dd, J = 16.9,
6.2 Hz, CH2O oxetanic ring), 4.12 (2H, s, CH2OTs), 2.47 (3H, s,
CH3 aromatic ring), 1.32 (3H, s, CH3).
thermogravimetric analysis (TGA) instrument in air at a heating rate
o
of 10 C/min. The molecular weights and the polydispersity index
were obtained with gel permeation chromatography (GPC; LC-20A,
Shimadzu) and the mobile phase was tetrahydrofuran (1.0 mL/min).
The hydroxyl value (OHV) of PAMMO was determined by the
acetic anhydride acetylation method.43
Synthesis of PTMMO.
1.85 g BF3•OEt2 (13.02 mmol), 1.20 g absolute ethyl alcohol
(26.00 mmol) and 25 mL dry methylene chloride were introduced
into a 100 mL three-neck flask equipped with a mechanical stirrer
and thermometer. This mixture was stirred for 0.5 h under argon at
(0–5) °C. A solution of 10 g TMMO (0.04 mol) in 20 mL methylene
chloride was added dropwise to this reaction mixture. The reaction
mixture was stirred at (0–5) °C for 18 h, and then the mixture was
allowed to reach 35 °C and maintained for 25 h. Thereafter, the
reaction was completed by adding 100 mL of saturated NaCl
solution. The organic layer was washed with water (200 mL×3) and
the mixture of water/methanol, dried over Na2SO4, and filtered and
evaporated in vacuum to produce 9.70 g of PTMMO, with a yield of
87%. UV-vis (CH2Cl2) λ/nm: 236, 262, 273. IR (KBr) v/cm-1: 2878
(vs CH2), 1598 (vas C-C aromatic ring), 1460 (δ CH2), 1358 (vas
S(=O)2), 1176 (vs S(=O)2), 1098 (δs C-H aromatic ring), 966 (vas C-
Synthesis
[60]Fullerene-poly(3-azidomethyl-3-methyl
oxetane)
(C60-
PAMMO) was synthesized in six steps, as shown in Scheme 1. First,
Ts protected 3-hydroxymethyl-3-methyl oxetane (TMMO) was
obtained via the reaction of 3-hydroxymethyl-3-methyl oxetane and
tosyl chloride. With the use of BF3•OEt2 as catalyst and ethanol as
initiator, TMMO was polymerized to produce monoethyl-terminated
PTMMO. The azide substitution of PTMMO resulted to afford the
monoethyl-terminated PAMMO. BM-PAMMO was synthesized by
esterifying and then brominating of PAMMO and malonyl
dichloride. Finally, BM-PAMMO was allowed to react with C60
through a modified Bingel reaction to get C60-PAMMO.
1
O-C, vas S-O-C), 833 (vs S-O-C ), 666 (ω C-H aromatic ring). H
NMR (CDCl3, 400 MHz) δ/ppm: 7.76–7.34 (4H, dd, J = 12.8, 7.8 Hz,
aromatic ring), 3.79 (2H, s, CH2OTs), 3.43-3.11 (2H, q, J = 10.0,
6.3Hz, CH2 ethyl), 3.07 (2H, s, CH2O main chain), 2.43 (3H, s, CH3
aromatic ring), 1.09-1.06 (3H, t, J = 4.8 Hz, CH3 ethyl), 0.75 (3H, s,
CH3). Molecular Weight (by GPC): Mw=1534, Mn=1225,
Mw/Mn=1.25.
Synthesis of PAMMO.
6.0 g NaN3, 18.0 g PTMMO and 30 mL DMSO were introduced
into a 100 mL three-neck flask equipped with a mechanical stirrer
and thermometer. The reaction mixture was stirred under 100 °C for
120 h. Thereafter, the reaction solution was poured into 200 mL
distilled water and extracted with dichloromethane (50 mL×3). The
organic layer was washed with distilled water (200 mL×3), dried
over Na2SO4, and filtered and evaporated in vacuum to produce 6.6
g of PAMMO, with a yield of 83%. UV-vis (CH2Cl2) λ/nm: 236,
284. IR (KBr) v/cm-1: 2972 (vas CH2), 2876 (vs CH2), 2102 (vas N3),
1282 (vs N3), 1455 (v CH2), 1378 (δs CH3), 1355 (v CH2), 1111 (vas
Scheme 1. Synthesis route of C60-PAMMO.
1
C-O-C). H-NMR (CDCl3, 400 MHz) δ/ppm: 0.94 (3H, s, CH3 side
Synthesis of TMMO.
chain), 1.14-1.22 (3H, t, J = 7.0 Hz, CH3 ethyl), 3.21 (4H, m, CH2O),
3.26 (2H, s, CH2N3), 3.69-3.33 (2H, q, J = 18.1 Hz, CH2 ethyl). 13C-
NMR (CDCl3, 100 MHz) δ/ppm: 75.68 (-CH2O-), 68.36 (HOCH),
67.07 (-CH2CH3), 55.53 (N3CH2CCH3), 40.80 (N3CH2CCH3), 18.06
(-CH2N3), 14.99 (-CH3). Molecular weight (by GPC): Mw=1027,
Mn=718, Mw/Mn=1.43. The hydroxyl equivalent weight was 80.07
mg/g.
20.97 g Tosyl chloride (0.11 mol) dissolved in 40 mL pyridine
was added slowly into a flask containing 10.20 g 3-hydroxymethyl-
3-methyl oxetane (0.10 mol). The mixture was reacted at -5 °C for
0.5 h under nitrogen atmosphere and then reacted at room
temperature for 12 h. The mixture was filtered and the filtrate was
added slowly into a vigorously stirred mixture of deionized water
(200 mL) and crushed ice, which was maintained under stirring for
another 2 h. A white precipitate appeared and was collected, washed
with cold water thrice, and dried under vacuum to obtain a white
powder of product (18.20 g, corresponding to a yield of 71.1%).
Elemental analysis (EA): Found/%: C, 58.54; H, 5.85; S, 12.48.
Calculated/%: C, 58.47; H, 5.88; S, 12.54. UV-vis (CH2Cl2) λ/nm:
205, 211, 237, 262, 273. IR (KBr) v/cm-1: 2875 (vs CH2), 1598 (vas C-
Synthesis of M-PAMMO.
0.25 mL of malonyl chloride (2.63 mmol) in 10 mL of dry CH2Cl2
was added dropwise to a stirred solution of 2.80 g of PAMMO (4.0
mmol hydroxyl group) and 0.60 mL DMF (7.78 mmol) in 25 mL dry
CH2Cl2 under Ar atmosphere in an ice bath, and the duration of this
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process was more than 30 min. The reaction mixture was stirred at
room temperature for 11 h and washed repeatedly with deionized
water to neuter. The organic layer was dried with anhydrous MgSO4,
filtered, and evaporated in vacuum to afford 2.0 g of brown M-
PAMMO, with a yield of 66%. UV-vis (CH2Cl2) λ/nm: 235, 335. IR
(KBr) v/cm-1: 2974 (vas CH2), 2877 (vs CH2), 2102 (vas N3), 1740 (v
C=O), 1279 (vs N3), 1456 (v CH2), 1377 (δs CH3), 1353 (v CH2),
Characterization of C60-PAMMO.
The structure of C60-PAMMO was confirmed by FT-IR, UV-vis,
1H NMR, and 13C NMR spectral analyses. The UV-vis spectra of
BM-PAMMO and C60-PAMMO are presented in Figure 1. As
shown in Figure 1, the UV-vis spectrum of BM-PAMMO shows an
absorption peak at 235 nm, which is ascribed to the π→π* transition
of the –N3 group. The UV-vis spectrum of C60-PAMMO also shows
a sharp absorption peak at approximately 235 nm, which implies the
presence of –N3 group in C60-PAMMO. Moreover, compared with
BM-PAMMO, three new absorption peaks at 258, 330 and 435 nm
are observed in the UV-vis spectrum of C60-PAMMO. The peaks at
258 and 330 nm are the characteristic absorption of the skeleton
structure of C60, and the weak absorption band at 435 nm is typical
of monoadducts at the closed 6,6-junction of C60.44,45
1
1112 (vas C-O-C). H-NMR (CDCl3, 400 MHz) δ/ppm: 0.94 (3H, s,
CH3 side chain), 1.14-1.22 (3H, t, J = 7.0 Hz, CH3 ethyl), 3.21 (4H,
m, CH2O), 3.26 (2H, s, CH2N3), 3.69-3.33 (2H, q, J = 5.3 Hz, CH2
ethyl), 3.33 (2H, s, COCH2CO). 13C-NMR (CDCl3, 100 MHz)
δ/ppm: 166.17 (-CH2COCH2-), 76.03 (HOCH-), 68.85 (-CCH2CH2-
), 66.82 (-CH2CH3), 55.56 (-CH2N3), 41.58 (N3CH2CCH3), 41.44 (-
COCH2CO-), 21.62 (-CCH3), 15.01 (-CH3). Molecular weight (by
GPC): Mw=2082, Mn=1520, Mw/Mn=1.37.
Synthesis of BM-PAMMO.
0.13 mL of Br2 (2.54 mmol) in 10 mL of dry CH2Cl2 was added
dropwise to a stirred solution of 3.1 g of M-PAMMO in 45 mL dry
CH2Cl2 at room temperature. Then the reaction mixture was stirred
at room temperature for 6 h. The reaction was terminated by adding
saturated NaBr solution. The mixture was washed with water until
the pH was neutral to obtain 2.9 g of BM-PAMMO, with a yield of
85%. UV-vis (CH2Cl2) λ/nm (log ε): 235 (4.89), 339 (3.98). IR
(KBr) v/cm-1: 2973 (vas CH2), 2877 (vs CH2), 2102 (vas N3), 1740 (v
C=O), 1279 (vs N3), 1455 (v CH2), 1377 (δs CH3), 1112 (vas C-O-C),
1
604 (v C-Br). H-NMR (CDCl3, 400 MHz) δ/ppm: 0.94 (3H, s, CH3
side chain), 1.14-1.22 (3H, t, J = 7.0 Hz, CH3 ethyl), 3.21 (4H, m,
CH2O), 3.26 (2H, s, CH2N3), 3.61-3.33 (2H, q, J = 6.4 Hz, CH2
ethyl), 5.54 (1H, s, CHBr). 13C-NMR (CDCl3, 100 MHz) δ/ppm:
166.17 (-CH2COCH2-), 76.03 (HOCH-), 68.85 (-CCH2CH2-), 66.82
(-CH2CH3), 55.56 (-CH2N3), 41.83 (-COCHBrCO-), 41.58
(N3CH2CCH3), 21.62 (-CCH3), 15.01 (-CH3). Molecular weight (by
GPC): Mw=2157, Mn=1586, Mw/Mn=1.36.
Figure 1. UV-vis absorption spectrum of BM-PAMMO and C60-
PAMMO. (a) C60-PAMMO and (b) BM-PAMMO
Synthesis of C60-PAMMO.
Figure 2 shows the FTIR spectra of BM-PAMMO and C60-
PAMMO. As shown in Figure 2(b), in the FTIR spectra of BM-
PAMMO, the peak at 1740 cm−1 can be assigned to the C=O
stretching vibration, and the peaks at 1112 cm−1 and 1279 cm−1
correspond to the C–O–C symmetric and antisymmetric stretching
vibrations. The strong absorption peak at 2102 cm−1 corresponds to
the -N3 group of PAMMO, and the peaks at 2973, 2934 and 2877
0.89 g C60 (1.24 mmol) and 0.556 g glycine (7.41 mmol) were
dissolved in 250 mL of chlorobenzene and 100 mL of DMSO by
using ultrasonic irradiation method. Thereafter, 1.21 g of BM-
PAMMO was added to the above solution. The mixture was stirred
at room temperature for 12 h, and then the resulting solution was
repeatedly washed with distilled water to remove DMSO and
glycine. Chlorobenzene was then removed under vacuum. The
residue was separated on a silica gel column through carbon
disulfide and CH2Cl2/ethyl acetate (1:2) as the eluent to obtain 44.30
mg unreacted C60 and 1.58 g of C60-PAMMO, with a yield of 87%
(based on the consumption of C60). UV-vis (CH2Cl2) λ/nm (log ε):
235 (4.85), 258 (4.86), 330 (4.35), 435 (3.22). IR (KBr) v/cm-1: 2965
(vas CH2), 2856 (vs CH2), 2096 (vas N3), 1736 (v C=O), 1262 (vs N3),
1456 (v CH2), 1384 (δs CH3), 1171 (C60 specific absorbing peak),
1103 (vas C-O-C), 526 (C60 specific absorbing peak). 1H-NMR
(CDCl3, 400 MHz) δ/ppm: 0.87 (3H, s, CH3 side chain), 1.16-1.08
(3H, t, CH3 ethyl), 3.15 (4H, m, CH2O), 3.19 (2H, s, CH2N3), 3.61-
3.33 (2H, q, CH2 ethyl). Molecular weight (by GPC): Mw=3255,
Mn=2276, Mw/Mn=1.43.
cm−1 are ascribed to the C-H symmetric and antisymmetric
39
stretching vibrations of PAMMO respectively.
The peak at 604
cm-1 is due to the C-Br stretching vibration. Compared with BM-
PAMMO (Figure 2(b)), the C-Br stretching vibration peak
disappeared in Figure 2(a). In addition, the new peaks in Figure 2(a)
at 526 cm-1 and 1171 cm-1 are the characteristic absorption peaks of
C60 cage. 46
Results and discussion
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Figure 2. ATR-FTIR absorption spectra of BM-PAMMO and C60-
Figure 4. 13C NMR spectrum of C60-PAMMO.
PAMMO. (a) C60-PAMMO and (b) BM-PAMMO.
The 13C NMR spectrum of C60-PAMMO is presented in Figure 4.
The signals of the carbonyl carbon (–C=O, denoted d) and the
quaternary carbon bounding to C60 (denoted c) appear at δ = 162.20–
163.00 ppm and δ = 50.20 ppm, respectively.47 The signals at around
74.00 and 71.20 ppm are attributed to the methylene carbons of the
main chain -CH2O- group (denoted f, k and i). The signals from
54.22 ppm to 52.34 ppm are attributed to the azidomethyl carbon of
the side chain -CH2N3 group (denoted h). The quaternary carbon
(denoted e) of the main chain appears at around 39.52 ppm. The
methyl carbons of the side chain (denoted g) and terminal
CH3CH2O- group (denoted j) appear at around 16.68 ppm and 20.89
ppm respectively. The two sp3-carbons of the C60 cage (denoted b)
appear at 68.34 ppm, and 58 sp2-carbons of fullerene cage (denoted
a) overlap and appear from 150.00 ppm to 135.40 ppm as a broad
peak.48
Thermal analysis
Figure 3. 1H NMR spectrum of C60-PAMMO.
The thermal stability of energetic materials has an important effect
on the preparation, storage, processing, and application scope. Thus,
DSC and TGA methods were adopted to evaluate the decomposition
behavior of C60-PAMMO.
The 1H NMR spectrum also confirmed the successful introduction
1
of PAMMO to C60 cage. Figure 3 shows the H NMR spectrum of
C60-PAMMO. As shown in Figure 3, the peaks at around 3.10 and
3.60 ppm are attributed to the methylene protons of the main chain -
CH2O- protons (denoted a and d) and the methylene protons of the
side chain -CH2N3 protons (denoted c). The methyl protons of the
CCH3 (denoted b) and CH3CH2O- (denoted e) appear at 0.75-1.20
ppm.
The DSC curve of C60-PAMMO under air atmosphere is showed
in Figure 5. Three exothermic peaks were observed from 100 °C to
600 °C. The first exothermic peak under atmosphere at 157 °C is
probably caused by the initial intramolecular or intermolecular
reaction of the -N3 group and fullerene carbon cage.49 The second
exothermic peak at 324 °C is due to the decomposition of PAMMO
main chain. The third peak at 513 °C can be attributed to the
decomposition of the C60 skeleton. In addition, the decomposition
enthalpies of the three exothermic peaks are 39 J/g, 2858 J/g and
1005 J/g respectively.
In order to well understand the thermal decomposition mechanism
of C60-PAMMO, thermogravimetric analysis tandem infrared
spectrum (TGA-IR) was used to rapidly identify the constituents of
the thermal decomposition gas (Figure 6). As shown in Figure 6(a),
the TGA and DTG curves show the three-step thermal degradation
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of C60-PAMMO under air atmosphere. The first thermal degradation
appears at 148 °C, with around 10.36% weight loss. Thereafter, two
thermal degradations appear at 323 °C and 512 °C with
approximately 35.99% and 51.91% weight losses, respectively.
Figure 6(b) shows the IR spectra of the thermal decomposition gas
of C60-PAMMO at 323 °C and 512 °C, respectively. As depicted in
Figure 6(a), the decomposed products of C60-PAMMO at 323 °C
under air atmosphere are mainly CO2 (2310 and 2367 cm-1), CO
(2185 and 2110 cm-1) and C=O (1749 cm-1), and the decomposed
products at 512 °C under air atmosphere are mainly CO2 (2302 and
2364 cm-1), CO (2109 and 2177 cm-1), N2O (2247 cm-1) and H2O
(3543 cm-1). Obviously, these results are different from the
previously reported that the thermal degradation of azide polymer
appears at around 200 °C, and the main gas products are CO, HCN,
HCHO and NH3. Thus, these results indicate that the first thermal
degradation of C60-PAMMO at 148 °C is probably due to the
decomposition of the -N3 group, and decomposition mechanism is
Scheme 2. The decomposition mechanism of C60-PAMMO.
In order to demonstrate this decomposition mechanism, in situ
probably through the initial intramolecular or intermolecular FTIR was used to rapidly identify the constituents of decomposition
condensed-phase residue. Figure 7(a) shows the infrared spectra of
C60-PAMMO decomposition condensed-phase residue at 27 °C, 127
°C, 152 °C, 172 °C, 207 °C and 262 °C under air atmosphere,
respectively. Figure 7 (b) shows the infrared absorption intensity
ratio of -N3 (v = 2096 cm-1) and C=O (v = 1736 cm-1), C60 (v = 526
cm-1) and C=O (v = 1736 cm-1) in C60-PAMMO decomposition
condensed-phase FTIR spectra at specified temperatures. As shown
in Figure 7, both the infrared absorption intensity ratio of -N3 (v =
2096 cm-1) and C=O (v =1736 cm-1) (A-N3/AC=O) and the infrared
absorption intensity ratio of C60 (v = 526 cm-1) and C=O (v = 1736
cm-1) (AC60/AC=O) were rapidly decreased at 148 °C. The decrease of
A-N3/AC=O shows that the -N3 started rapid decomposition at 148 °C,
and the reduction of AC60/AC=O at 148 °C indicates that the
decomposition of -N3 group is accompanied with the damage of
fullerene conjugated structure. Thus, in situ FTIR analytical results
strictly corroborate the TGA-IR analyses that C60-PAMMO
decomposition at 148 °C is through the initial intramolecular or
intermolecular reaction of -N3 and the fullerene carbon cage.
cycloaddition of -N3 and fullerene carbon cage and subsequent
decomposition to release nitrogen (Scheme 2).
Figure 5. DSC curve of C60-PAMMO under air atmosphere.
Figure 8. (a) IR spectra of the thermal decomposition remaining
solid of C60-PAMMO at 27, 127, 152, 172, 207 and 262 °C
respectively; (b) Ratio of the IR absorption peak of -N3 (v = 2096
cm-1)/-COO- (v = 1736 cm-1) and C60 (v = 526 cm-1)/C=O (v = 1736
cm-1) at different temperatures.
Figure 7. (a) TGA and DTG curves of C60-PAMMO under
atmosphere; (b) IR spectrum of the thermal decomposition gas of
C60-PAMMO at 323 °C and 512 °C under atmosphere; (c) Thermal
decomposition gas intensity under different temperature.
Conclusions
A new energetic polymer, [60]fullerene-poly(3-azidomethyl-3-
methyl oxetane) has been successfully synthesized through the
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VJieowuArrtnicalelONnlainme e
ARTICLE
DOI: 10.1039/C5RA16892A
Bingel reaction of BM-PAMMO and C60. Its structure was 16 M. H. Veen, B. Boer, U. Stalmach, K. I. Wetering and G. Hadziioannou,
systematically characterized by FTIR, UV-vis, 1H NMR and 13C
Macromolecules., 2004, 37, 3673-3684.
NMR spectroscopy analyses. The thermal stability and thermal 17 E. Rusen, B. Marculescu, N. Preda and L. Mihut, J. Polym. Res., 2008, 15,
decomposition mechanism of [60]fullerene-poly(3-azidomethyl-3- 447-451.
methyl oxetane) was analyzed by DSC. TGA-FTIR, and in situ 18 P. Ravinder and V. Subramanian, Theor. Chem. Acc., 2012, 131, 1-11.
FTIR. The results showed that the initial decomposition of 19 M. A. Hiskey, N. Goldman and J. R. Stine, J. Energ. Mater., 1998, 16,
[60]fullerene-poly(3-azidomethyl-3-methyl oxetane) at 148 °C could
119-127.
be ascribed to the intramolecular or intermolecular reaction of the - 20 J. P. Agrawal, Prog. Energy Combust. Sci., 1998, 24, 1-30.
N3 group and fullerene carbon cage.
21 M. B. Talawar, R. Sivabalan, T. Mukundan, H. Muthurajan, A. K. Sikder,
B. R. Gandhe and A. S. Rao, J. Hazard. Mater., 2009, 161, 589-607.
22 D. M. Badgujar, M. B. Talawar, S. N. Asthana and P. P. Mahulikar, J.
Hazard. Mater., 2008, 151, 289-305.
Acknowledgements
We are grateful for financial support from the National
Natural Science Foundation of China (Project No. 21301142,
51372211), National Defense Fundamental Research Projects
(Project No. A3120133002), Applied Basic Research Program
of Sichuan Province (2014JY0170) and Southwest University
of Science and Technology Researching Project (13zx9107,
13zxfk09, 14tdfk05).
23 A. K. Sikder and S. Nirmala, J. Hazard. Mater., 2004, 112, 1-15.
24 R. Singh, D. Srivastava and S. K. Upadhyay, Polym. Sci. Ser. B., 2012,
54, 88-93.
25 F. Cataldo, O. Ursini and G. Angelini, Carbon., 2013, 62, 413-421.
26 N. X. Wang, Propellants Explos. Pyrotech., 2001, 26, 109-111.
27 B. Jin, J. Shen, R. F. Peng, Y. J. Shu, S. J. Chu and H. S. Dong, Polym.
Degrad. Stab., 2012, 97, 473-480.
28 S. Brochu and G. Ampleman, Macromolecules., 1996, 29, 5539-5545.
29 B. Jin, J. Shen, R. F. Peng, Y. J. Shu, S. J. Chu and H. S. Dong, J. Polym.
Res., 2012, 19, 1-9.
Notes and references
a(State Key Laboratory Cultivation Base for Non-metal Composites and
Functional Materials, Southwest University of Science and Technology,
Mianyang 621010, P, R, China)
30 A. M. Kawamoto, U. Barbieri, T. Keicher, H. Krause, J. A. Saboia
Holanda, M. Kaiser and G. Polacco, Propellants Explos. Pyrotech., 2008,
33, 365-372.
Email: jinbo0428@163.com
rfpeng2006@163.com
31 I. K. Varma, V. Choudhary, B. Gaur, B. Lochab, S. Oberoi and R.
Chauhan, J. Appl. Polym. Sci., 2006, 101, 779-786.
32 T. M. Klapötke and J. Stierstorfer, Cent. Eur. J. Energ. Mater., 2008, 5,
13-30.
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/b000000x/
33 Y. M. Mohan and K. M. Raju, Des. Monomers Polym., 2005, 8, 159-166.
34 A. A. Albarran, E. Silantyeva and K. S. Seo, Polym. Chem., 2014, 5,
4710-4714.
1 H. W. Kroto, A. W. Allaf and S. P. Balm, Chem. Rev., 1991, 91, 1213-
1235.
2 P. R. Birkett, Annu. Rep. Prog. Chem. Sect. A: Inorg. Chem., 1999, 95,
35 M. S. Eroğlu and O. Güven, Polymer., 1998, 39, 173-176.
36 P. Sreekumar and H. G. Ang, Polym. Degrad. Stab., 2007, 92, 1365-1377.
37 Y. M. Mohan and K. M. Raju, Int. J. Polym. Mater., 2006, 55, 203-217.
38 X. N. Zhang, G. G. Xu, J. P. Xu and W. M. Wang, Chin. J. Explos.
Propellant., 1999, 22, 33-36.
431-451.
3 P. A. Troshin and R. N. Lyubovskaya, Russ. Chem. Rev., 2008, 77, 323-
369.
4 A. D. Darwish, Annu. Rep. Prog. Chem. Sect. A: Inorg. Chem., 2010, 106,
356-375.
39 U. Barbieri, G. Polacco and E. Paesano, Propellants Explos. Pyrotech.,
2006, 31, 369-375.
5 M. D. Tzirakis and M. Orfanopoulos, Chem. Rev., 2013, 113, 5262-5321.
6 X. Han, T. F. Wang, Z. K. Lin, D. L. Han, S. F. Li and F. Q. Zhao, Defence
Sci. J., 2009, 59, 284-293.
40 T. Huang, B. Jin, R. F. Peng and S. J. Chu, Int. J. Polym. Anal. Charact.,
2014, 19, 522-531.
7 T. Heintz, H. Pontius, J. Aniol, C. Birke, K. Leisinger and W. Reinhard,
Propellants Explos. Pyrotech., 2009, 34, 231-238.
8 A. J. Bellamy and S. L. Dearing, Propellants Explos. Pyrotech., 2002, 27,
352-360.
41 X. Guan, L. Li, J. Zheng and G. Li, RSC Advance., 2011, 1, 1808-1814.
42 B. Jin, J. Shen, R. F. Peng, R. Z. Zheng and S. J. Chu, Tetrahedron Lett.,
2014, 55, 5007-5010.
43 M. H. Tavassoli-Kafrani, J. M. Curtis and F. R. van de Voort, J. Am. Oil
Chem. Soc., 2014, 91, 925-933.
9 J. J. Liu, Z. J. Liu, J. Cheng and D. Fang, J. Solid State Chem., 2013, 200,
43-48.
44 F. Diederich, L. Isaacs and D. Philp, Chem. Soc. Rev., 1994, 23, 243-255.
45 M. Maggini, G. Scorrano and M. Prato, J. Am. Chem. Soc., 1993, 115,
9798-9799.
10 H. J. Huang, H. S. Dong, M. Zhang and Y. Xi, Energ. Mater., 2005, 13, 7-
10.
11 J. C. Lynch, J. M. Brannon and J. J. Delfino, J. Chem. Eng. Data., 2002,
47, 542-549.
46 W. Krӓtschmer, L. D. Lamb, K. Fostiropoulos, D. R. Huffman, Nature,
1990, 347, 354-358.
12 S. Tomohiro, H. Ryota, H. Maki and S. Hideo, Synth. Commun., 2014, 44,
275-279.
47 D. Sigwalt, F. Schillinger, S. Guerra, M. Holler, M. Berville and J. F.
Nierengarten, Tetrahedron Lett., 2013, 54, 4241-4244.
48 F. Cheng, X. Yang, H. Zhu and Y. Song, Tetrahedron Lett., 2000, 41,
3947-3950.
13 M. Prate, Q. C. Li and F. Wudl, J. Am. Chem. Soc., 1993, 115, 1148-1150.
14 X. H. Dong, W. B. Zhang, Y. W. Li, M. J. Huang, S. Zhang and P.
Roderic, Polym. Chem., 2012, 3, 124-134.
49 S. González, N. Martín, A. Swartz and D. M. Guldi, Org. lett., 2003, 5,
557-560.
15 M. D. Yan, S. X. Cai and F. W. John, J. Org. Chem., 1994, 59, 5951-
5954.
6 | J. Name., 2012, 00, 1-3
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