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incorporation of rigid and bulky groups such as diphenyl or
naphthalene in the main chains leads to an increase in the
temperature of the glass transition. Considerable attention has
been devoted to the preparation of novel poly(aryl ether ketone)s
containing diphenyl or naphthalene moieties due to their high-
temperature performance [22–26]. Wu et al. [27] reported the
synthesis of soluble aromatic poly(ether ketone)s containing
diphenyl moieties and fluorine groups via a nucleophilic aromatic
substitution polycondensation, all the polymers formed trans-
parent, strong, and flexible films having low dielectric constants
and low water absorptions. Guiver et al. [28] reported the synthesis
of aromatic poly(ether ketone)s containing diphenyl moieties and
sulfonic acid groups by a mild sulfonation method for proton
exchange membranes. Zolotukhin et al. [12] reported the synthesis
of naphthalene-containing poly(aryl ether ketone)s by the precip-
itation electrophilic polycondensation, the polymers obtained
possessed high Tgs values (>180 ꢀC) and also too high Tms values
(>380 ꢀC), which made it difficult to process. To expand the
application of PAEKs, their melt processabilities and thermal
properties need to be improved by reducing the melting temper-
ature and increasing the glass-transition temperature. Poly(aryl
ether ketone)s containing both diphenyl moiety and amide linkages
in the main chains are expected to combine high Tg values and the
other attractive features of aromatic polyamides with the excellent
chemical, solvent, and stress-crack resistance of the poly(aryl ether
ketone)s. In this paper, we synthesized two new monomers, 4,40-
bis(4-phenoxybenzoyl)diphenyl (BPOBDP) and N,N0-bis(4-phe-
noxybenzoyl)-p-phenylenediamine (BPBPPD), via simple synthetic
procedures from readily available materials. A series of novel pol-
y(aryl ether ketone)s containing both diphenyl moiety and amide
linkages in the main chains were prepared by the modified elec-
trophilic Friedel–Crafts solution copolycondensation of iso-
phthaloyl chloride (IPC) with a mixture of BPOBDP and BPBPPD,
over a wide range of BPOBDP/BPBPPD molar ratios, in the presence
of anhydrous AlCl3 and N-methylpyrrolidone (NMP) in 1,2-dichlo-
roethane (DCE).
(Shanghai Chemical Reagent) and p-phenoxybenzoic acid
(Shanghai Chemical Reagent) were used as received.
2.2. Measurements
Elemental analysis was performed with Perkin–Elmer Model
2400 CHN analyzer. The FT-IR spectra of the monomers and poly-
mers in KBr pellets (2%) were recorded using a Nicolet FT-IR (510P)
spectrophotometer. 1H NMR (400 MHz) and 13C NMR (100 MHz)
spectra were obtained with a Bruker PC-A400 (400 MHz) spec-
trometer at an operating temperature of 25 ꢀC using DMSO-d6 or
CDCl3/CF3CO2H as a solvent. Mass spectra were obtained on a Fin-
nigan 4510 mass spectrometer. Inherent viscosities were obtained
with a concentration of 0.2 g/dL in 95% H2SO4 at 25 ꢀC using an
Ubbelhode suspended level viscometer. Differential scanning
calorimetry (DSC) measurements were performed on a Mettler
Toledo DSC 821e instrument at a heating rate of 10 ꢀC/min under
nitrogen. The glass-transition temperature (Tg) was taken in DSC
curve as the center of the step transition in the second heating run.
Thermogravimetric analysis (TGA) was performed on a Netzch Sta
449c thermal analyzer system at a heating rate of 10 ꢀC/min in
nitrogen. The mechanical properties were measured at 25 ꢀC using
a Shimadzu AG-2000A tester at a crosshead speed of 5 mm/min.
The samples are dog bone shape and have dimensions of
2.0 ꢁ 4.0 ꢁ 20 mm3. The temperatures for the polymers to process
are 20 ꢀC higher than the Tms. At least five samples for each poly-
mer were tested, and the average value was reported. Wide-angle
X-ray diffraction (WAXD) was measured with a Rigaku D/MAX-IIA
X-ray diffractometer, using CuK
a radiation, at 30 kV and 20 mA.
The diffractograms were recorded at 25 ꢀC over the range of 10–
40ꢀ. Samples were powder.
2.3. Monomer synthesis
2.3.1. Synthesis of 4,40-bis(4-bromobenzoyl)diphenyl (1)
To a 100 mL round-bottomed flask was added 4-bromobenzoyl
chloride (24.15 g, 0.11 mol), diphenyl (7.7 g, 0.05 mol), anhydrous
powdered aluminum chloride (20 g, 0.15 mol) and o-dichloroben-
zene (60 mL) with stirring under nitrogen at 0 ꢀC. The suspension
was stirred at room temperature for 1 h and at 90 ꢀC for 8 h. The
reaction mixture was poured into cold aqueous hydrochloric acid,
then the water was decanted off and the residue was washed with
water several times. Next, methanol was added to the oily residue
to precipitate a solid. Finally, the crude product was recrystallized
from DMF and dried under vacuum at 100 ꢀC to afford 21.5 g of
white crystals (1).
2. Experimental
2.1. Materials
All reagents and solvents were of analytical grade and were used
without further purification unless stated otherwise. 4-Bromo-
benzoyl chloride and isophthaloyl chloride (IPC) (Shuanglin
Chemical Co., China) were purified by distillation under vacuum
prior to use. 1,2-Dichloroethane (DCE, Shanghai Chemical Reagent),
N-methylpyrrolidone (NMP, Shanghai Chemical Reagent),
N,N-dimethylacetamide (DMAc, Shanghai Chemical Reagent), N,N-
dimethylformamide (DMF, Shanghai Chemical Reagent) and
o-dichlorobenzene (Shanghai Chemical Reagent) were purified by
distillation and dried by 0.4 nm molecular sieve. Aluminum chlo-
ride (Shanghai Chemical Reagent) was sublimed prior to use.
p-Phenylenediamine (Shanghai Chemical Reagent), phenol
Yield: 83%. m.p.: 338–339 ꢀC. IR (KBr, cmꢂ1): 1647, 1605, 1583,
852, 749; 1H NMR (DMSO-d6,
d, ppm): 7.90 (d, J ¼ 8.4 Hz, 4H), 7.77
(d, J ¼ 8.4 Hz, 4H), 7.72 (d, J ¼ 8.4 Hz, 4H), 7.66 (d, J ¼ 8.4 Hz, 4H); MS
(EI, 70 eV): m/z 522 (Mþ, 81Br, 18), 520 (Mþ, 35), 518 (Mþ, 79Br, 17),
363 (48), 185 (97), 183 (100), 152 (46), 76 (42). Anal. Calcd. for
C26H16O2Br2: C, 60.01; H, 3.10. Found: C, 59.73; H, 2.88.
O
C
O
C
AlCl3, 90 oC
+
Br
COCl
Br
Br
o-dichlorobenzene
1
OK
NMP, 200 oC
O
O
O
C
C
O
(BPOBDP)
2
Scheme 1. Synthesis of 4,40-bis(4-phenoxybenzoyl)diphenyl (BPOBDP).