Synthesis and characterization of new aromatic Co-polyamides

Article abstract of DOI:10.14233/ajchem.2014.19010

Six new aromatic Co-polyamides CoP₁-CoP₆ were prepared by direct Yamazaki's polycondensation reaction of various aliphatic and aromatic dicarboxylic acid (adipic acid, phthalic acid, terephthalic acid and 4-phenylenediacrylic acid) with new various types of aromatic diamine monomers: monomers containing flexible linkages (methylene group), Schiff-base diamine monomer and diamine monomer containing pyridine heterocyclic group and bearing bulky aromatic pendant groups in the 4-position of the pyridine ring, in the presence of LiCl in pyridine and triphenyl phosphite as condensing agents in N-methyl-2-pyrrolidinone as solvent. 4-Phenylenediacrylic acid (PPDAA) was prepared by the condensation reaction of terephthalaldehyde with malonic acid in the presence of pyridine. The monomers were characterized by FTIR and ¹H NMR. The resulting polyamides were characterized by FTIR and ¹H NMR and their physical properties including solubility, thermal stability and thermal behaviour were studied as well. All of these new polymers show good solubility in polar aprotic solvents and very good thermal stability.

Full text of DOI:10.14233/ajchem.2014.19010

Asian Journal of Chemistry; Vol. 26, Supplementary Issue (2014), S45-S52
ASIAN JOURNAL OF CHEMISTRY
http://dx.doi.org/10.14233/ajchem.2014.19010
Synthesis and Characterization of New Aromatic Co-Polyamides
MOHAMMED A. MUTAR
Department of Chemistry, College of Education, University of Al-Qadisiya, Al Diwaniyah, Qadisiyyah Province, Iraq
Corresponding author: E-mail: mohammeddw73@gmail.com
Published online: 24 December 2014;
AJC-16436
Six new aromatic Co-polyamides CoP1-CoP6 were prepared by direct Yamazaki's polycondensation reaction of various aliphatic and
aromatic dicarboxylic acid (adipic acid, phthalic acid, terephthalic acid and 4-phenylenediacrylic acid) with new various types of aromatic
diamine monomers: monomers containing flexible linkages (methylene group), Schiff-base diamine monomer and diamine monomer
containing pyridine heterocyclic group and bearing bulky aromatic pendant groups in the 4-position of the pyridine ring, in the presence
of LiCl in pyridine and triphenyl phosphite as condensing agents in N-methyl-2-pyrrolidinone as solvent. 4-Phenylenediacrylic acid
(PPDAA) was prepared by the condensation reaction of terephthalaldehyde with malonic acid in the presence of pyridine. The monomers
were characterized by FTIR and 1H NMR. The resulting polyamides were characterized by FTIR and 1H NMR and their physical properties
including solubility, thermal stability and thermal behaviour were studied as well. All of these new polymers show good solubility in polar
aprotic solvents and very good thermal stability.
Keywords: Co-polyamides, Aromatic Co-polyamides, Aromatic diamine monomers.
can be formed and blocks of copolymer can create their own
crystallites4,5.
INTRODUCTION
Thermal characteristics are very important for all polymers
processed by moulding, injection or spinning. This applies
not only to the melting temperature, but also the temperature
of decomposition, the crystallization temperature and other
characteristics. In addition, the enthalpies of melting and
crystallization are important for semi-crystalline polymers as
well. The DSC study of all components of blends (used for
any product prepared via melting) therefore gives basic
information about the components' future behaviour in the
blend and during processing1.
During the copolyamide formation both mechanisms are
applicable, but different to such an extent that there are formed
block rather than statistic copolyamides6.
In the present paper the synthesis of a new types of
aromatic Co-polyamides from various aliphatic and aromatic
dicarboxylic acid (e.g., adipic acid, phthalic acid, terephthalic
acid and 4-phenylenediacrylic acid) with new aromatic diamines,
has been reported whose light scattering and dilute solution
behavior have been published elsewhere7,8. The polyconden-
sation is carried out in the presence of triphenyl phosphite
(TPP) in N-methyl-2-pyrrolidinone (NMP), pyridine mixture,
containing 3 wt. % LiCl by the method of Yamazaki et al.9.
Because of the low solubility of Co-polyamides, the poly-
condensation reaction terminates quickly and results in low
molecular weight products. In order to do away with this
problem, the polycondensation is carried out in the presence
Some properties of homopolymers are not always satis-
fying for their application in certain fields. Copolymer monomer
based on a certain monomer with some amount of another,
functional co-monomer may have specific characteristics
which predestine this copolymer as raw material for products
with better properties, or as an additive for homopolymer and
may thus improve the properties of the product. Copolymers
are able to improve many properties, including thermal pro-
perties2,3.
of LiCl10,11
.
EXPERIMENTAL
Copolymer has one great advantage, good compatibility
with relevant homopolymers and from this point of view the
deterioration of the blend properties is lower. Semi-crystalline
(block) copolymers can co-crystallize with homopolymers,
several type of crystals with various sizes and levels of perfection
Fourier transform infrared (FTIR) spectra were recorded
on a SHIMADZU-FTIR-8400S spectrometer (Japan) with KBr
pellets in the optical range of 4000-400 cm-1. 1H NMR spectra
were registered using a Bruker, 250 MHz, spectrometer, at
Polymer Laboratories Co. Iran using DMSO as a solvent.

S46 Mutar
Asian J. Chem.
Differential scanning calorimetry (DSC) were measurements
by DSC 131 Evo, Setaram, (France) using a heating rate of
10 °C/min in N2 atmosphere within the temperature range of
(30-600 °C). The sample weight used approximately (10 mg )
mg. The peaks are used to determine the thermal properties of
the samples. The solubility of the polymers was determined
with (0.01 g) of a Co-polymer in (2 mL) of a solvent.
O2N
NO2
H2N
NH2
N
N
10 % Pd/C-ethanol
H2N·NH2·H2O-THF
85 °C; 5 h
Scheme-II: Synthesis of M1
N-Methyl-2-pyrrolydinone (NMP) from (ALFA-
PRODUCTS); absolute methanol, acetic acid, lithium chloride,
palladium on charcoal 10 %, from (BDH, England); dichloro-
methane from (Biosolve); ammonium acetate, malonic acid
and adipic acid from (Chem-supply). Hydrochloric acid,
salicylaldehyde, from (HiMedia); diethyl ether from (IGCC,
England); aniline, 3-chloroaniline, 2-bromoaniline, calcium
chloride, benzaldehyde, 2,6-diamino pyridine, dimethyl sulph-
oxide (DMSO), glacial acetic acid, m-cresol, N,N-dimethyl-
acetamide, 1,4-phenylene diamine, phthalic acid, terephthalic
acid, piperidine, pyridine, terephthalaldehyde, triphenyl
phosphite (TPP), tetrahydrofurane (THF), all from (MERCK);
absolute ethanol from (Scharlab S.L); acetone, p-nitroaceto-
phenone, all from (ALDRICH); N,N-dimethylformamide
(DMF) from (Sinopharm Chemical Reagent); and hydrazine
monohydrate from (THOMAS-BAKER).
the condensation of terephthalaldehyde (3 g, 22 mmol) and
2,6-diamino pyridine (5 g, 46 mmol) in 15 mL of methanol,
by boiling the mixture under reflux at 120 °C for 3 h. The
precipitate was filtered and recrystallized from methanol and
dried in a vacuum desiccators16 to yielding 6.8 g (98 % wt) of
white crystals; m.p. 71-74 °C (Scheme-III).
CHO
N
H2N
2
NH2 Methanol
120 °C; 3 h
+
H2N
N C
H
C
H
NH2
N
N
N
CHO
Scheme-III: Synthesis of M2
Synthesis of 2-[bis(4-aminophenyl)methyl]phenol
[M3]: To a 0.1 M solution of H2SO4 in methanol ( 60 %: 40 %),
aniline (2 g, 21 mmol) and salicylaldehyde (1.2 g, 10 mmol)
were added and the mixture was refluxed at 120 °C for 10 h
with constant stirring. Upon completion of the reaction, the
solvent was removed under vacuum and to the residue water
(2 × 25 mL) and then CH2Cl2 (50 mL) were added. The organic
extract was dried over anhydrous17 Na2SO4 to yielding 2.3 g
(79 % wt.) of deep yellow crystals: m.p. 75-95 °C (Scheme-
IV).
Synthesis of monomers
Synthesis of 4-phenyl-2,6-bis(4-nitrophenyl)pyridine
(PNPP): In a round-bottomed flask (150 mL) equipped with
a reflux condenser, a mixture of benzaldehyde (1.6 g, 15
mmol), p-nitro acetophenone (5 g, 30 mmol), ammonium
acetate (15 g) and glacial acetic acid (37.5 mL) was refluxed
at 140-142 °C for 2 h. Upon cooling, crystals separated, which
were filtered and washed first with acetic acid (50 %) and
then with cold ethanol. These dark yellow crystals were recrys-
tallized from absolute ethanol and then dried at 60 °C under
vacuum12,13 to produce 4.88 g (82 % wt.) of very-deep yellow
crystals: m.p. 240-244 °C (Scheme-I):
CHO
OH
H
C
NH2
(60 % H2SO2; 40 %)
methanol
NH2
H2N
+
2
OH
120 °C; 10 h
Scheme-IV: Synthesis of M3
The other diamino compounds were prepared by the same
procedure as above using 3-chloro aniline with salicylaldehyde
(M5), 2-bromo aniline with salicylaldehyde (M6), 3-chloro
aniline with acetone (M7), 2-bromo aniline with acetone (M8),
respectively, are shown in (Table-1) (Schemes V to VIII).
O2N
NO2
CH3
C
CHO
N
O
Ammonium acetate
glacial acetic acid
+
2
140-142 °C; 2 h
NO2
Cl
Cl
Scheme-I: Synthesis of [PNPP]
H
CHO
OH
NH2
H2SO4:Methanol
60: 40
C
H2N
NH2
Synthesis of 4-phenyl-2,6-bis(4-aminophenyl)pyridine
(PAPP) [M1]: (2 g, 5 mmol) of the (PNPP), 0.2 g of 10 %
Pd/C and 100 mL of ethanol were introduced into a three-
necked flask to which 20 mL of hydrazine monohydrate was
added dropwise over a period of 1 h at 85 °C.After completing
the addition, the reaction was continued at reflux temperature
for another 4 h. To the suspension, 40 mL of THF was added
to re-dissolve the precipitated product and refluxing was
continued for 1 h. The mixture was filtered to remove the
Pd-C and the filtrate was poured into water. The product was
filtered off, washed with hot water and dried in vacuum14,15 to
yielding 1.45 g (85 % wt.) of light brown crystals: m.p. 105 °C
(Scheme-II).
+
2
OH
120 °C; 10 h
Cl
Scheme-V: Synthesis of M4
Br
Br
H
C
CHO
OH
NH2
H2SO4:Methanol
60: 40
H2N
NH2
Br
2
+
OH
120 °C; 10 h
Scheme-VI: Synthesis of M5
Cl
Cl
NH2
H2SO4:Methanol
60: 40
CH3
C
O
H2N
NH2
H3C–C–CH
3 + 2
120 °C; 10 h
Cl
CH3
Synthesis of 1,4-Bis(6-aminopyridin-2-ylimino)-
dimethylene benzene [M2]: This monomer was prepared by
Scheme-VII: Synthesis of M6

Vol. 26, Suppl. Issue (2014)
Synthesis and Characterization of New Aromatic Co-Polyamides S47
TABLE-1
SYNTHESIS AND PHYSICAL PROPERTIES OF MONOMERS (M4, M5, M6, M7)
Substance
Weight
(g)
Yield
(% wt)
Monomers
Color
Deep green
Deep brown
Black
m.p. (°C)
240 Decomp.
130 Decomp.
Viscous
Benzaldehyde
derived or acetone
1.22 g (10 mmol)
Aniline or derived
2.69 g (21 mmol)
M4 [2-(bis(4-amino-3-
chlorophenyl)methyl)phenol]
M5 [2-(bis(4-amino-3-
bromophenyl)methyl)phenol]
M6 [4,4'-(propane2,2-diyl)bis(2-
chloroaniline)]
2.6
3.36
2.3
72
75
78
76
3.6 g (21 mmol)
2.69 g (21 mmol)
3.6 g (21 mmol)
1.22 g (10 mmol)
0.58 g (10 mmol)
0.58 g (10 mmol)
M7 [4,4'-(propane2,2-diyl)bis(2-
bromoaniline)]
2.9
Black
Viscous
NH2
Br
Br
was filtered and washed by methanol and hot water and then
dried at 100 °C for 12 h in vacuum19 (Scheme-X and XI).
H2SO4:Methanol
CH3
O
Br
60: 40
H2N
C
NH2
H3C–C–CH
3 + 2
120 °C; 10 h
CH3
RESULTS AND DISCUSSION
Scheme-VIII: Synthesis of [M7]
The FTIR spectrum of (PNPP) indicated absorption band
at (1500 cm-1), (1340 cm-1) to (-NO2) asymmetric and symme-
tric stretching, respectively, absorption bands around (1676-
1622 cm-1) show the presence of the aromatic ring and (1550-
1520 cm-1) to heteroaromatic ring (C=N).
Synthesis of 4-phenylenediacrylic acid [ PPDAA]: In a
100 mL round-bottomed flask were added terephth-alaldehyde
(3.48 g, 26 mmol), malonic acid (8.27 g, 94 mmol) to 30 mL
of pyridine containing small amount of piperidine. The reaction
mixture was stirred for 2 h at 45 °C, 4 h at 80 °C and 3 h at 110
°C, respectively. The solution was poured into large amount
of distilled water and neutralized with 10 % HCl to obtain
white precipitate. The precipitate was filtered, washed with
water, acetic acid and acetone and then dried in a vacuum
oven at room temperature18 to give 5.1 g (90 % wt) of white
crystals; m.p. 222-225 °C (Scheme-IX).
In the FTIR spectrum of (M1), the characteristic absor-
ptions of the nitro group disappeared and (-NH2) stretching
absorption bands of the amino group appeared at (3380 cm-1).
1H NMR spectrum of (M1), is assigns the following
chemical shifts; δ(2.5) ppm for DMSO, 5.6 (s, 4H) for NH2
group, δ(6.1-8.5) ppm (s, 15H ) for ArH group.
The FTIR spectrum of (M2 Schiff-base) which indicates
absorption bands at (3625 cm-1) to (-NH2 group), (3070 cm-1)
to (aromatic -CH stretching), (2916 cm-1) to (aliphatic -CH
stretching), absorption bands around (1610-1542 cm-1) show
the presence of the aromatic ring and (1519-1504 cm-1) to
heteroaromatic ring (C=N).
HOOC C
H
C
H
C
H
C COOH
H
Scheme-IX: Structure of PPDAA
Synthesis of Co-polyamides [CoP1-CoP6]: A typical
procedure was described as follows. In a three-necked flask
equipped with a reflux condenser and N2 inlet, dicarboxylic
acid and diamines (Table-2) were added. Then (2 g) dried
lithium chloride, (14 mL) N-methyl-2-pyrrolidinone, (2.8 mL)
pyridine and (2.8 mL) triphenyl phosphite were charged. The
resulting mixture was reacted at 120 °C for 2 h under the
nitrogen atmosphere. After the polymerization, the viscous
mixture was poured into (200 mL) methanol. The Co-polymer
The FTIR spectrum of (M3) indicated absorption bands
at (3440 cm-1) to (-NH2 group), absorption band at (3370 cm-1)
to (-OH group), (3108 cm-1) to (aromatic -CH stretching),
(2905 cm-1) to (aliphatic -CH stretching) and absorption bands
around (1606-1540 cm-1) show the presence of the aromatic
ring.The characteristic absorption of (C=O aldehyde) disappeared.
The FTIR spectrum of (M4) indicated absorption bands
at (3415 cm-1) to (-NH2 group), absorption band at (3388 cm-1)
TABLE-2
SYNTHESIS OF CO-POLYAMIDES (CoP1-CoP6)
Monomers
Diacid
(g/mmol)
Diamine
(g/mmol)
Co-polyamides
Yield (% wt)
Color
Diacid
Diamine
PPDAA
Terephthalic acid
PPDAA
M3
/
0.654 / 3
0.332 / 2
0.654 / 3
0.332 / 2
0.654 / 3
0.332 / 2
1.450 / 5
/
CoP1
CoP2
CoP3
80
79
80
Light green
Brown
M4
/
1.800 / 5
/
Terephthalic acid
PPDAA
Terephthalic acid
M7
1.920 / 5
/
Light brown
/
1,4-Phenylene
diamine
M1
Phthalic acid
/
0.830 / 5
/
0.324 / 3
0.710 / 2
CoP4
82
Yellow
1,4-Phenylene
diamine
M6
Phthalic acid
/
0.830 / 5
/
0.324 / 3
0.600 / 2
CoP5
CoP6
81
79
Brown
Brown
Adipic acid
/
M2
M5
0.730 / 5
/
0.948 / 3
0.896 / 2

S48 Mutar
Asian J. Chem.
CaCl2/pyrldine
H
C
TPP/NMP
H2N–
NH2
+
–COOH
+
HOOC–
–C=C–COOH
H
H
HOOC–C=C–
H
H
OH
110 °C; 3h-N2
O
O
C
O
O
H
N
H
N
H
H
H
N
H
C
H
C
C–C=C–
H H
C
C
C
H
C
H
x-1
x
OH
OH
CoP1
Cl
Cl
CaCl2/pyrldine
TPP/NMP
H
C
NH2
H2N–
+
HOOC–
–COOH
+
HOOC–C=C–
H
–C=C–COOH
H
H
H
OH
110 °C; 3h-N2
Cl
Cl
Cl
Cl
O
O
O
C
H
O
H
H
N
H
N
H
C
H
C
C–C=C–
H H
C
H
C
H
C
N
C
N
x-1
x
OH
OH
CoP2
Br
Br
CaCl2/pyrldine
TPP/NMP
CH3
C
H2N–
+
HOOC–
–COOH
+
HOOC–C=C–
H
–C=C–COOH
H
H
NH2
H
CH3
110 °C; 3h-N2
Br
Br
Br
Br
O
CH3
C
O
C
O
C
H
N
O
H
H
N
CH3
H
H
C–C=C–
H H
C
H
C
H
C
N
C
x-1
x
CH3
CH3
CoP3
Scheme-X: Synthesis of CoP1-CoP3

Vol. 26, Suppl. Issue (2014)
Synthesis and Characterization of New Aromatic Co-Polyamides S49
N
H2N
CaCl2/pyridine
TPP/NMP
NH2
COOH
H2N
NH2
+
+
COOH
110 °C; 3 h-N2
O
H
N
O
C
O
H
H
O
C
H
H
N
N
C
C
N
x-1
X
CoP4
Cl
Cl
COOH
CH3
C
CaCl2/pyridine
TPP/NMP
H2N
NH2
+
+
NH2
H2N
COOH
CH3
110 °C; 3 h-N2
Cl
Cl
H
N
H
N
O
C
O
C
H
H
N
O
O
CH3
C
N
C
C
x-1
x
CH3
CoP5
Br
Br
CaCl2/pyridine
H
C
N
N
TPP/NMP
CH
HOOC
COOH
+
H2N
NH2
H2N
N
C
H
C
H
N
+
NH2
2 4
110 °C; 3 h-N2
OH
Br
Br
H
N
O
C
O
C
O
C
H
O
C
H
N
H
N
N
H
C
H
N
CH2
N
C
H
C
H
N
CH
2 4
4
x-1
x
OH
CoP6
Scheme-XI: Synthesis of CoP4-CoP6

S50 Mutar
Asian J. Chem.
to (-OH group), (3107 cm-1) to (aromatic -CH stretching),
(2918 cm-1) to (aliphatic -CH stretching) and absorption bands
around (1608-1510 cm-1) show the presence of the aromatic
ring and (721 cm-1) to (C-Cl). The characteristic absorption of
(C=O aldehyde) disappeared.
1H NMR spectrum of (M4), assigns the following chemical
shifts; δ (2.5) ppm for DMSO, δ(5.8) ppm (s, 1H) for C-H
group, 6.2 (s, 4H) for NH2 group, δ(6.3-8.6) ppm (s, 10H) for
ArH group, 6.01 (s, 1H, OH) δ (2.135) ppm (s, 2H ) for N-OH
group.
band at (1619 cm-1) to (C=O amide), (1537 cm-1) to vinyl
segment and (748 cm-1) to (C-Br).
The FTIR spectrum of (CoP4) which indicated absorption
band at (3210 cm-1) to (aromatic-CH stretching), absorption
bands around (1654-1633 cm-1) show the presence of the
aromatic ring, (1570-1511 cm-1) to heteroaromatic ring (C=N)
and the sharp band at (1588 cm-1) to (C=O amide).
1H NMR spectrum of (CoP4), assigns the following
chemical shifts; δ (2.5) ppm for DMSO, δ (6.1) ppm (s,1H )
for N-H group, δ (6.7 -8.5) ppm for Ar-H group.
The FTIR spectrum of (M5) indicated absorption bands
at (3415 cm-1) to (-NH2 group), absorption band at (3376 cm-1)
to (-OH group), (3103 cm-1) to (aromatic -CH stretching),
(2932 cm-1) to (aliphatic -CH stretching) and absorption bands
around (1614-1521 cm-1) show the presence of the aromatic
ring and (552 cm-1) to (C-Br). The characteristic absorption of
(C=O aldehyde) disappeared.
1H NMR spectrum of (M5), assigns the following chemical
shifts; δ (2.5) ppm for DMSO, δ(6.2) ppm (s, 1H) for C-H
group, 6.0 (s, 4H) for NH2 group, δ(6.2 -8.9) ppm (s, 10H) for
ArH group, 5.7 (s, 1H, OH) group.
The FTIR spectrum of (CoP5) which indicated absorption
bands at (3213 cm-1) to (aromatic -CH stretching), (2943 cm-1)
to (aliphatic -CH stretching), absorption bands around (1608-
1538 cm-1) show the presence of the aromatic ring, the sharp
band at (1630 cm-1) to (C=O amide) and (818 cm-1) to (C-Cl).
The FTIR spectrum of (CoP6) which indicated absorption
band at (3315 cm-1) to (-OH group), (3207 cm-1) to (aromatic
-CH stretching), absorption bands around (1645-1627 cm-1)
show the presence of the aromatic ring, (1547-1498 cm-1) to
heteroaromatic ring (C=N), the band at (1634 cm-1) to (C=O
amide) and (687 cm-1) to (C-Br).
The FTIR spectrum of (M6) indicated absorption bands
at (3425 cm-1) to (-NH2 group), absorption band at (3100 cm-1)
to (-OH group), (3107 cm-1) to (aromatic -CH stretching),
(2918 cm-1) to (aliphatic -CH stretching) and absorption bands
around (1608-1510 cm-1) show the presence of the aromatic
ring and (725 cm-1) to (C-Cl). The characteristic absorption of
(C=O aldehyde) disappeared.
Differential scanning calorimetry study: From the DSC
curves, the glass transition temperature (Tg), the crystallization
temperature (Tc) and the melting temperature (Tm) were
measured. The endothermic peaks of copolyamides are related
to melting temperature. This increased in Tm is assigned to the
linear terephthalic acid and p-phennylenediacrylic acid
moieties incorporated into the polymer back bone during
synthesis of co-polyamide. Hence , Tm is higher fore CoP1,
CoP2, CoP4 and CoP5 as the polymer chain more rigid parts
and/or a polymer contains less free volume. Samples usually
showed multiple endotherms which are explained as due to
the fusion of different population of crystallites with different
sizes. As expected , Tm values are lower for CoP3 and CoP6)
due to the higher chain flexibility of the formers afforded with
increasing the amount of methylene of polymeric back bone
and steric hindrance of terminal functional groups can influence
Tm of resultant polymers. In addition, the polymer CoP6, has
the lowest thermal stability than the other polymers containing
rigid pyridine and phenylene moieties. This behaviour can be
explained by the presence of methylene units which are more
The FTIR spectrum of (M7) indicated absorption bands
at (3415 cm-1) to (-NH2 group), absorption band at (3300 cm-1)
to (-OH group), (3100 cm-1) to (aromatic -CH stretching),
(2932 cm-1) to (aliphatic -CH stretching) and absorption bands
around (1614-1523 cm-1) show the presence of the aromatic
ring and (554 cm-1) to (C-Br). The characteristic absorption of
(C=O aldehyde) disappeared.
The FTIR spectrum of (CoP1) indicated absorption bands
at (3378 cm-1) to (-OH group), (3208 cm-1) to (aromatic -CH
stretching), (2901 cm-1) to (aliphatic -CH stretching), absorp-
tion bands around (1610-1536 cm-1) show the presence of the
aromatic ring, the sharp band at (1616 cm-1) to (C=O amide)
and (1544 cm-1) to vinyl segment.
1H NMR spectrum of (CoP1), assigns the following chemical
shifts; δ (2.5) ppm for DMSO, δ (8.5) ppm for HC=CH δ (6.3-
8.6) ppm (s, 10H ) for ArH group, 5.7 (s, N-H) group.
The FTIR spectrum of (CoP2) which indicated absorption
bands at (3335 cm-1) to (-OH group), (3123 cm-1) to (aromatic
-CH stretching), (2915 cm-1) to (aliphatic -CH stretching),
absorption bands around (1603-1511 cm-1) show the presence
of the aromatic ring, the sharp band at (1621 cm-1) to (C=O
amide), (1524 cm-1) to vinyl segment and (808 cm-1) to (C-Cl).
1H NMR spectrum of (CoP2), assigns the following
chemical shifts; δ (2.5) ppm for DMSO, δ (6.2) ppm (s, 1H)
for C-H group, 6.0 (s, 4H) for NH2 group, δ (6.2 -8.9) ppm (s,
10H) for ArH group, 5.7 (s, 1H, OH) group.
vulnerable to thermo-oxidative processes21-23
.
Glass transition temperature (Tg) of all co-polyamides
were in the range (236-254 °C), in case of copolyamides (CoP1,
CoP2, CoP3, CoP4, CoP5 and CoP6) it is interesting to note that
the change of the diacids had a noticeable Tg difference. In
addition, endothermic peaks above their glass transition tempe-
ratures were observed in DSC scans, which may be attributed
to the crystalline molecular structure for all co-polamides. The
higher in Tg of (CoP1, CoP2, CoP4 and CoP5) compared to that
analogous co-polyamides might be endorsed to the existence
of hetroaromatic pyridine rings and phenylene moieties. This
increased in Tg is assigned to the linear terephthalic and p-
phennylenediacrylic acids moieties incorporated into the
polymer back bone during synthesis of co-polyamide. Parti-
cularly, the end group contribution becomes significant24. Thus
it will be interesting to introduce different chain ends using
substitution reaction since end group modification in (CoP1,
The FTIR spectrum of (CoP3) which indicated absorption
bands at (3200 cm-1) to (aromatic -CH stretching), (2923 cm-1)
to (aliphatic -CH stretching), absorption bands around (1610-
1549 cm-1) show the presence of the aromatic ring, the sharp

Vol. 26, Suppl. Issue (2014)
Synthesis and Characterization of New Aromatic Co-Polyamides S51
CoP2, CoP3 and CoP5) had a strong effect on Tg as observed in
previous studies24-26. Usually, amore polar functional group
causes Tg to be higher. Tg of co-polyamides may be strongly
dependent on the inter-association of functional groups with
the neighboring molecule as well as the volume fraction
occupied by terminal groups26. It seems that several factors
such as the rigidity, polarity, length and steric hindrance of
terminal functional groups can influence Tg of resultant
polymers. DSC data indicated that the CoP3 containing
symmetric dimethyl substituted resulted in lower Tg value than
that of unsubstituted co-polyamides. The consideration of
segmental symmetry is useful in explaining this behavior. The
dimethyl substitution leads to an symmetric segment which
can result in less efficient chain packing and hence more free
volume that led to relatively easier chain mobility of polymer
segments in comparison with asymmetrical substituted and
unsubstituted Co-polyamides, ultimately leading to decrease
in glass transition temperature. The Tg, Tm and Tc obtained
from DSC are reported in Table-3.
TABLE-4
SOLUBILITY OF CO-POLYAMIDES: CoP1-CoP6
Co-Polyamides
Solvent
CoP1
CoP2
CoP3
CoP4
+++
+ -
CoP5
+ -
++
+ -
++
+ -
+ -
++
+ -
++
+ -
CoP6
+ -
+ -
++
+ -
++
+ -
+ -
++
++
++
DMAc
DMF
++
++
++
++
++
++
NMP
+ -
+ -
+ -
++
Pyridine
m-Cresol
THF
+ -
++
++
++
+++
++
+++
++
+++
+ -
+++
+ -
CHCl3
+ -
+ -
++
++
CH2Cl2
DMSO
Conc. H2SO4
++
+++
+++
++
++
+ -
+++
++
++
++
+ -
++
Full soluble +++; Soluble at room temp. ++; Partially soluble + -
and infrared spectroscopy confirmed the molecular compo-
sition of six strictly alternating, highly ordered Co-polyamides
having methylene chains as flexible spacers and phenylene or
pyridine hetryclic groups as the rigid segments. From the DSC
curves, the glass transition temperature, the crystallization
temperature and the melting temperature were measured. All
the polymers showed a glass transition temperature, in the
range of 236-256 °C. The higher in Tg of ( CoP1, CoP2, CoP4
and CoP5) compared to that analogous Co-polyamides might
be endorsed to the existence of hetroaromatic pyridine rings
and phenylene moieties. This increased in Tg is assigned to
the linear terephthalic and p-phennylenediacrylic acids
moieties incorporated into the polymer back bone during
synthesis of Co-polyamide. In the same time, the presence of
symmetric dimethyl substituted together with ether linkages
brings much more flexibility to the macromolecular chain and
decreases the glass transition of the polymers CoP3 and CoP6.
The melting temperatures of the CoP3 and CoP6 decrease with
increasing the amount of methylene of polymeric backbone
and steric hindrance of terminal functional groups. The CoP6
has the lowest melting point among the series of the result and
Co-polyamides . Tm is higher fore CoP1, CoP2, CoP4 and CoP5
as the polymer chain more rigid parts and/or a polymer contains
less free volume. All of these new polymers show good
solubility in polar aprotic solvents and good thermal stability.
TABLE-3
THE GLASS TRANSITION, MELTING TEMPERATURE AND
CRYSTALLIZATION TEMPERATURE OBTAINED FROM DSC
Samples
CoP1
CoP2
CoP3
CoP4
CoP5
CoP6
Tm (°C)
510
Tg (°C)
248
Tc (°C)
272
531
254
288
461
236
272
502
240
264
510
250
290
416
238
290
Solubility of Co-polyamides: Solubility of Co-polyamides
CoP1-CoP6 was qualitatively tested in organic solvents and the
results are summarized in (Table-4). The method that attempt
to enhance their processabilities and solubilities were either
by introducing bulky groups, flexible linkages, or molecular
asymmetry into the polymer backbones. In this work, the
attachment of bulky pendant groups in polymer backbone not
only could provide an enhanced solubility because of decreased
packing density and crystallinity, but also could impart an
increase in Tg by restricting the segmental mobility27.
One of the major objectives of this work was producing
Co-polyamides with improved solubility. The solubility was
investigated as 0.02 g of polymeric sample in 5 mL of solvent.
All of the newly synthesized Co-polyamides have good soluble
in common polar and dipolar aprotic solvents without need
for heating.
REFERENCES
1. M. Kristofic and A. Ujhelyiova, Fibres Textiles in Eastern Europe, 14,
21 (2006).
2. M. Pielichowski and A. Leszczynska, J. Therm. Anal. Calorim., 78,
631 (2004).
3. G. Zhu,Y. Li, J. Yin, J. Ling and Z. Shen, J. Therm. Anal. Calorim., 77,
833 (2004).
Conclusion
4. M. Kristofic,A. Marcincin andA. Ujhelyiova, J. Therm. Anal. Calorim.,
60, 357 (2000).
Six new aromatic Co-polyamides have been synthesized.
For this purpose, a typical polycondensation process has been
followed under mild conditions. The reaction variables, such
as temperature, time, monomer concentration, solvent system
etc. have been found to have strong influence on the molecular
weight of the polymers. Synthesis of Co-polyamides conta-
ining methylene unit, Schiff-base linkages and pyridine hetero
cyclic ring with adipic acid, phthalic acid, terephthalic acid
and 4-phenylenediacrylic acid, respectively at 120 °C for 2 h
under the nitrogen atmosphere. The polymers were charac-
terized by proton nuclear magnetic resonance spectroscopy
5. R. Loffler and P. Navard, Macromolecules, 25, 7172 (1992).
6. M. Kristofic,A. Marcincin andA. Ujhelyiova, J. Therm. Anal. Calorim.,
60, 357 (2000).
7. S. Ali, Br. Polym. J., 10, 108 (1978).
8. S. Ali, Eur. Polym. J., 15, 685 (1979).
9. N. Yamazaki, M. Matsumoto and F. Higashi, J. Polym. Sci., Polym.
Phys. Ed., 13, 1373 (1975).
10. S.P. Papkov, V.G. Kulichikhin, V.D. Kalmykova and A.Y. Malkin, J.
Polym. Sci., Polym. Phys. Ed., 12, 1753 (1974).
11. L.H. Gan, P. Blais, D.J. Carlsson, T. Suprunchuk and D.M. Wiles, J.
Appl. Polym. Sci., 19, 69 (1975).
12. B. Tamami and H. Yeganeh, Polymer, 42, 415 (2001).
13. B. Tamami and H. Yeganeh, Eur. Polym. J., 38, 933 (2002).

S52 Mutar
Asian J. Chem.
14. S. Mehdipour-Ataei, M. Hatami and M. Hossein Mosslemin, Chinese
J. Polym. Sci., 27, 781 (2009).
22. S.-H. Hsiao and L.-M. Chang, High Perform. Polym., 12, 285 (2000).
23. R. Hariharan, G. Anuradha, S. Bhuvana, M. Saroja Devi and M.Anitha,
J. Polym. Res., 11, 239 (2004).
15. S. Mehdipour-Ataei, Y. Sarrafi, M. Hatami and L. Akbarian-Feizi, Eur.
Polym. J., 41, 491 (2005).
24. S. Mehdipour-Ataei, M. Hatami and M. Hossein Mosslemin, Macro-
molecules, 27, 1968 (1994).
16. I. Kaya, A. Bilici and M. Sacak, J. Inorg. Organomet. Polym., 19, 443
(2009).
25. K.L. Wooley, C.J. Hawker, J.M. Pochan and J.M.J. Frechet, Macro-
molecules, 26, 1514 (1993).
17. R.J. Sarma and J.B. Baruah, Dyes Pigments, 61, 39 (2004).
18. K. Faghihi, J. Sci. I.A.U, 18, 56 (2008).
26. B.I. Voit, J. Polym. Sci. A Polym. Chem., 38, 2505 (2000).
27. X. Zhao, C. Wang, L. Chen and M. Zhu, Colloid Polym. Sci., 287,
1331 (2009).
19. T. Chen, M. Zhang and X. Tang, Chinese J. Polym. Sci., 26, 793 (2008).
20. S. Mehdipour-Ataei and H. Heidari, Macromol. Symp., 193, 159 (2003).
21. D. Wilson, H.D. Stenzenberger and P.M. Hergenrother, Polyimides,
Glasgow Black and Sons (1990).