Synthesis and characterization of thiophene containing bismaleimide and polyaspartimides

Article abstract of DOI:10.14233/ajchem.2013.13514

New class of aromatic bismaleimide containing thiophene ring were synthesized from bis-[(4-aminophenoxy)-6-naphthalene]-3-methyl- 2-thiophenyl methane (BANTM) and maleic anhydride via bismaleamic acid as the intermediate followed by cyclodehydration. The structure of the monomers was confirmed by FTIR, ¹H NMR and ¹³C NMR. Further, a series of polyaspartimides were synthesized by addition reaction of bismaleimide with various diamines. The polymers were characterized by FTIR, ¹H NMR and ¹³C NMR. The polymers exhibit good solubility in organic solvents such as NMP, DMF and DMSO. The T_g and T₁₀ % of the polyaspartimides are in the range of 199-212 °C and 379-487 °C respectively.

Full text of DOI:10.14233/ajchem.2013.13514

Asian Journal of Chemistry; Vol. 25, No. 2 (2013), 1089-1094
http://dx.doi.org/10.14233/ajchem.2013.13514
Synthesis and Characterization of Thiophene Containing Bismaleimide and Polyaspartimides
*
R. SIVASANKARI, B. GOVINDARAJ and M. SAROJADEVI
Department of Chemistry, College of Engineering Guindy, Anna University, Chennai-600 025, India
*Corresponding author: Tel: +91 44 22358655; E-mail: msrde2000@yahoo.com
(Received: 28 January 2012;
Accepted: 30 August 2012)
AJC-12050
New class of aromatic bismaleimide containing thiophene ring were synthesized from bis-[(4-aminophenoxy)-6-naphthalene]-3-methyl-
2-thiophenyl methane (BANTM) and maleic anhydride via bismaleamic acid as the intermediate followed by cyclodehydration. The
structure of the monomers was confirmed by FTIR, 1H NMR and 13C NMR. Further, a series of polyaspartimides were synthesized by
addition reaction of bismaleimide with various diamines. The polymers were characterized by FTIR, 1H NMR and 13C NMR. The polymers
exhibit good solubility in organic solvents such as NMP, DMF and DMSO. The Tg and T10 % of the polyaspartimides are in the range of
199-212 ºC and 379-487 ºC respectively.
Key Words: Thiophene containing bismaleimides-polyaspartimides, FT-IR, Thermal properties.
bulky pendent group is expected to decrease the close packing
of polymer chains which decreases the intermolecular
forces of attraction thereby improving the processability of
the polymer4.
Hence, in present study a new thiophene containing diamine
monomer (BANTM) was synthesized. Using the same amine,
bismaleimide and polyaspartimides were also synthesized.
These monomers and polymers were characterized using by
FT-IR, 1H NMR, 13C NMR spectral techniques. The solubility,
thermal and inherent viscosity properties were studied.
INTRODUCTION
Bismaleimides are thermosetting polymers which have
wide applications in microelectronic and aerospace industries
for making advanced composites1. They show excellent thermal
and mechanical properties which make them the suitable
material for use in structural applications. They also exhibit
good fatigue resistance. Their usage in composites is more
advantageous in comparison to condensation type polyimides
even though the later exhibit better thermal and electrical prop-
erties. This is because condensation type polyimides evolve
volatile by products during ring formation which decreases
their stability and hence utility.
Bismaleimides can be further polymerized through the
double bond present in maleimide ring, which are electron
deficient due to the presence of electron withdrawing carbonyl
group on both sides. These double bonds can be polymerized
to give highly cross linked polymer or they can be polymerized
further by addition of nucleophilic difunctional reagents to
give linear polymer2. Polyaspartimides are a class of polyimides
which are linear and possess more facile properties. Poly-
aspartimides also have good thermal stability. The chemical
modifications such as incorporation of flexible ether linkage
on the main chain and/or introduction of bulky pendent group
on the diamine help in producing a wide class of bismaleimides
and polyaspartimides with improved utility. Presence of flexible
ether linkage would decrease the rigidity and also lower the
energy of internal rotation of the polymer chain, decrease the
crystallinity and improve the solubility3. Incorporation of a
EXPERIMENTAL
Acetone, 3-methyl-thiophene-2-carboxaldehyde, p-phenylene
diamine, β-naphthol were purchased from Sisco Research
Laboratories Pvt. Ltd. Maleic anhydride (E-Merck, India), N-
methyl2-pyrrolidone (Aldrich, USA), acetic anhydride (Fischer
scientific chemicals, India) sodium acetate (Spectrochem,
India), were used as received. 4,4'-Diamino diphenyl methane
(DDM), 4,4',3,3'-benzophenonetetracar-boxylic acid dianhy-
dride and pyromellitic dianhydride were purchased from
Qualigen fine chemicals, India. N,N-dimethyl formamide
(Fluka, USA) was purified by refluxing with calcium hydroxide,
distilled under reduced pressure and stored over molecular
sieves (4 Å).
Nicolet Impact 400 Fourier transform infrared (FT-IR)
spectrometer was used to examine the structure of the pre-
1
cursors, monomers, prepolymers and polymers. H and 13C
NMR spectral analysis were undertaken with acetone-d6,
deuterated dimethyl sulphoxide (DMSO-d6) as solvents and

1090 Sivasankari et al.
Asian J. Chem.
tetramethylsilane (TMS) as reference and recorded on Bruker
NMR 400 spectrometer. TGA was performed to assess the
thermal stability of the polymers.
and symmetric stretching vibration of CH3 group). 1H NMR
(400 MHz,CDCl3, ppm); δ 8.15 (d, 4H, a), δ 7.18 (d, 4H, b), δ
6.96 (d, 2H ,c), δ 7.59 (d, 2H, d), δ 6.99 (s, 2H, e), δ 7.47 (d,
2H, f). δ 7.16 (d, 2H, g), δ 5.34 (s, 2H, h), δ 2.21 (s, 3H, i), δ
6.50 (d, 1H, j), δ 6.57 (d, 1H, k). 13C NMR (400 MHz, CDCl3,
ppm); δ C1-141-5, C2-120.8, C3-118.4, C4-163.1, C5-152.1,
C6-117.4, C7-129.3, C8-109, C9-132.7, C10-129.1, C11-125.6,
C12-128.5, C13-132.8, C14-40.1, C15-135.1, C16-128.5, C17-133.9,
C18-124.7, C19-124.1.
Thermograms were obtained using a TA instruments Q100
series thermo gravimetric analyzer. Differential scanning calori-
metric analysis was performed on a TA instruments Q10 series.
Inherent viscosity was determined to get an idea about the
molecular weight of the polyimides. The measurements were
conducted at 30 ºC in DMAc/NMP solvent using Cannon
Ubbelohde viscometer. Wide angle X-ray diffraction measure-
ments were performed at room temperature (about 25 ºC) on
a X-pert PAN analytical X-ray diffractometer using CuKα
radiation. The scanning rate was 20 ºC/min over a range of 2θ
= 5-40º. The UV studies were carried out in Shimadzu UV-
1601 spectrophotometer.
Synthesis of diamine
bis-[(4-Aminophenoxy)-6-naphthalene]-3-methyl-2-
thiophenyl-methane (BANTM): In a 250 mL three-necked
round bottomed flask equipped with a condenser, dropping
funnel and nitrogen inlet, bis-[(4-nitrophenoxy)-6-naphtha-
lene]-3-methyl-2-thiophenyl-methane (3 g, 0.00470 m) and
reductive iron (0.15 g, 0.0047 m) were taken. To this mixture,
0.2 mL of conc. HCl and 10 mL of 50 % aqueous ethanol
were added slowly. The mixture was refluxed with stirring for
3 h and 1 mL of ammonium hydroxide solution (10 wt %)
was added slowly during 10 min. The mixture was filtered hot
to remove the solvent5. The light brown solid obtained was
the diamine monomer, which was further purified by recrysta-
llization from ethanol. Yield 75 % (m.p. 152-155 ºC). FT-IR
(KBR, cm-1): 3448, 3336 (asymmetric and symmetric
stretching vibration of NH2 group); 2913, 2989 (asymmetric
and symmetric stretching vibration of CH3 group); 1614
(N-H bending vibration); 1233, 1156 (asymmetric and sym-
Synthesis of precursor-I (diol)
bis-[(6-Hydroxynaphthalene)-3-methyl-2-thiophenyl]-
methane (BHMN): 1.4 g (0.0792 m) of β-naphthol was
charged in to a three-necked round bottomed flask equipped
with a reflux condenser, Dean-Stark apparatus and nitrogen
inlet. To this 4.27 mL (0.0396 m) of 3-methyl-thiophene-2-
carboxaldehyde, 1.56 g (0.0792 m) of p-toluene sulphonic acid
monohydrate and 60 mL of toluene were added. The reaction
mixture was refluxed at 130 ºC for 18 h under nitrogen atmos-
phere. Water produced by the reaction was removed as
azeotrope with toluene. The reaction mixture was cooled and
20 mL of 10 % aqueous solution of NaOH was added and the
resulting solution was stirred. The product obtained was
filtered, washed with methanol and dried. The resulting solid
was recrystallized from ethanol.Yield 94 %; m.p. 170 ºC. FT-
IR (KBR cm-1); 3543, 3440 (asymmetric and symmetric
stretching vibration of OH group); 2943, 2983 (asymmetric
and symmetric stretching vibration of C-H bond of CH3 group).
1H NMR (400 MHz, CDCl3, ppm); δ 5.35 (s, 2H, a), δ 7.15 (d,
2H, b), δ 7.92 (d, 2H, c), δ 7.41 (s, 2H, d), δ 7.80 (d, 2H, e), δ
7.16 (d, 2H, f). δ 5.34 (s, 1H, g), δ 2.21 (s, 3H, h), δ 6.50 (d,
1H, i), δ 6.77 (d, 1H, j), δ 7.47 (s, 2H, k). 13C NMR (400 MHz,
CDCl3, ppm); δ C1-154-7, C2-117.4, C3-129.3, C4-109,
C5-132.7, C6-129.0, C7-125.6, C8-128.5, C9-132.8, C10-40.1,
C11-135.1, C12-12.2, C13-133.9, C14-124.7, C15-124.1.
1
metric stretching vibration of C-O-C group). H NMR (400
MHz,CDCl3, ppm); δ 4.0 (s, 4H, a) δ 6.42 (d, 4H, b), δ 6.67
(d, 4H, c), δ 6.96 (d, 2H, d), δ 7.59 (d, 1H, e), δ 6.99 (s, 1H, f),
δ 7.47 (s, 2H, g), δ 7.16 (d, 1H, h), δ 5.34 (s, 1H, i), δ 2.21 (s,
3H, j), δ 6.50 (d, 1H, k), δ 6.77 (d, 1H, l). 13C NMR (400
MHz, CDCl3, ppm); δ C1-141-5, C2-116, C3-118, C4-147, C5-
152, C6-117, C7-109, C8-129.3, C9-132.7, C11-129, C12-126.7,
C13-132.8, C14-40.1, C15-132.8, C16-12.2, C17-124.7, C18-124.1.
Synthesis of bismaleimide: Bismaleimides were prepared
by reacting the diamines BANTM with maleic anhydride.
BANTM (1 g, 0.00322 mol) was dissolved in 2.5 mL of DMF
in a 250 mL three necked round bottomed flask equipped with
a nitrogen inlet and an addition funnel. Maleic anhydride (0.61
g, 0.00644 mol) dissolved in DMF (2.5 mL) was added
dropwise. The reaction mixture was stirred at room tempe-
rature for 2 h. Viscous solution of bismaleiamic acid was
formed. To this solution acetic anhydride (5 mL) and sodium
acetate (0.5 g) were added. The temperature was maintained
at 52-55 ºC with stirring for 6 h. The slurry formed was poured
into ice-cold water to yield BMI. The formed BMI was filtered
and thoroughly washed with ethanol6.Yield 76 %; m.p. 196 ºC.
FT-IR (KBR, cm-1): 1782, 1712 (asymmetric and symmetric
stretching vibration of C=O group); 2966, 2917 (asymmetric
and symmetric stretching vibration of CH3 group); 1358 (C-
N-C stretching vibration); 692 (due to meleimide ring (C=C)).
1H NMR (400 MHz, CDCl3, ppm); δ 6.94 (d, 4H, a), δ 7.60 (d,
4H, b), δ 6.90 (d, 4H, c), δ 6.96 (d, 2H, d), δ 7.59 (d, 2H, e), δ
6.99 (s, 2H, f), δ 7.47 (d, 2H, g), δ 7.16 (d, 2H, h), δ 5.34 (s,
1H, i), δ 2.21 (s, 3H, j), δ 6.50 (d, 2H, k), δ 6.77 (d, 1H, l), δ
7.42 (s, 2H, m). 13C NMR (400 MHz, CDCl3, ppm); δ C1-135-
9, C2-161.8, C3-125.9, C4-121.3, C5-117.7, C6-152.6, C7-152.1,
C8-117.4, C9-109.0, C10-129.3, C11-132.7, C12-129.0, C13-125.6,
Synthesis of precursor-II (dinitro compound)
bis-[(4-Nitrophenoxy)-6-naphthalene]-3-methyl-2-
thiophenyl-methane (BNNM): To a 250 mL three-necked
round bottomed flask equipped with a nitrogen inlet, Dean-
Stark trap and a condenser, were added (3.9 g, 0.0252 m) bis-
[(6-hydroxynaphthalene)-3-methyl-2-thiophenyl]methane
(BHNM), p-chloronitrobenzene (5 g, 0.0126 m), anhydrous
potassium carbonate (1.7 g, 0.0126 m) and DMAc (20 mL).
After the mixture was stirred for 1 h, 35 mL of dry toluene
was added, the reaction temperature was raised slowly and
the generated water was removed from the reaction mixture
by azeotropic distillation. The reaction temperature was raised
to 155 ºC and kept at this temperature for 20 h. The resultant
reaction mixture was cooled and poured into ice-cold water.
The precipitate was filtered and dried in vacuum oven at 60 ºC.
The crude product was purified by recrystallization from ethanol
to produce pale yellow crystals.Yield 85 %; m.p. 120 ºC. FT-
IR (KBR cm-1): 1517, 1347 (asymmetric and symmetric
stretching vibration of NO2 group); 2958, 2988 (asymmetric

Vol. 25, No. 2 (2013)
Synthesis and Characterization of Thiophene Containing Bismaleimide and Polyaspartimides 1091
C14-126.7, C15-128.5, C16-132.3, C17-40.1, C18-133.9, C19-19.2,
C20-133.9, C21-124.7, C22-124.1.
The diamine monomer show absorption bands around
3348 and 3412 cm-1 due to N-H symmetric and asymmetric
stretching vibrations and the absorption band around 1612-
1629 cm-1 is due to the N-H bending vibration.
Synthesis of polyaspartimides: Polyaspartimides were
synthesized by Michael addition reaction of biamaleimides
with aromatic heterocyclic diamine (BANTM). The bismale-
imide (1 g, 0.002321 mol) was dissolved in m-cresol (3.5 mL)
in a three necked round bottomed flask fitted with a nitrogen
inlet and condenser. The mixture was stirred at room tempe-
rature for 0.5 h. When bismaleimide was completely dissolved,
the diamine (0.716 g) was added to the reaction mixture and
then 0.1 mL of glacial acetic acid was added. The mixture
was stirred at 100-110 ºC for 96 h. Then, the mixture was
poured into excess ethanol with vigorous stirring. The preci-
pitate was filtered and washed thrice with ethanol. All other
polyaspartimides were synthesized by adopting a similar
procedure7. FT-IR (KBR cm-1): 3400, 3331 (asymmetric and
symmetric stretching vibration of N-H group); 1777, 1710
(asymmetric and symmetric stretching vibration of C=O
group); 2989, 2917 (asymmetric and symmetric stretching
vibration of CH3 group); 1358 (C-N-C stretching vibration).
The absorptions around 2989 and 2912 cm-1 due to the
C-H stretching vibration of CH3 group as shown in Fig. 1.
RESULTS AND DISCUSSION
Synthesis of precursors and monomers: The precursor
(BHNM) were synthesized from 3-methyl thiophene-2-
carboxaldehyde and β-naphthol in the presence of toluene/
p-toluene sulphonic acid. The structure of the precursor was
0500
4000
3000
2000
1500
1000
Wavenumber (cm–1
)
Fig. 1. FT-IR Spectrum of MMNB
1
confirmed by FT-IR, H and 13C NMR. The precursors-2
1H NMR spectrum also confirm the structure of the diamine
(BANTM) monomer. The signal at 4 ppm corresponds to
amino proton and that at 2.16 ppm correspond to the three
methyl protons. All aromatic protons give signals between
6-8 ppm, as shown in Fig. 2a. 13C NMR spectrum are shown
in Fig. 2b, the methyl carbon of the monomer resonate at 12.3
ppm.The methine carbon of the diamine resonate at 40 ppm.
All aromatic carbons resonate around 120-162 ppm.
Synthesis of bismaleimide: The synthesized diamine
(BANTM) was reacted with required amount of maleic anhy-
dride to give bismaleiamic acid. The bismaleiamic acid was
then cyclodehydrated using dehydrating agent acetic anhydride
and sodium acetate to get a bismaleimide (BMI-1) as shown
in Scheme-II.
(BNNM) was synthesized by the reaction of the BHNM with
1-chloro-4-nitro benzene in the presence of potassium carbo-
nate. Finally, the dinitro compound was reduced by hydro-
chloric acid and iron to form the diamine monomers BANTM
as shown in Scheme-I.
OH
CH3
OH
CH3
Toluene/PTSA
130oC
+ 2
CH
CHO
S
S
2
Cl
NO2
120oC
DMF/K2CO3
24hrs
OH
O
NO2
CH3
CH3
CH
S
(2a)
O
O
NH2
NH2
CH
NO2
S
O
Fe/HCl
aq.C2H5OH
O
NH2
CH3
CH
S
NH2
O
8
7
6
5
4
3
2
1
0
δ ppm
Scheme-I: Synthesis of BANTM

1092 Sivasankari et al.
Asian J. Chem.
100
80
60
40
20
0
CH3
(2b)
O
O
NH2
NH2
CH
S
3500
2500
1500
)
0500
Wavenumber (cm–1
160
140
120
100
80
δ ppm
60
40
20
0
Fig. 3. FT-IR spectra of bismaleimide
1
Fig. 2. (a) H NMR spectrum of BANTM and (b) 13C NMR spectrum of
1
BANTM
The H NMR spectrum (Fig. 4a) of bismaleimide show
the distinct signal around 7.26 ppm due to four olefinic protons.
The absence of signal at 10.5 ppm due to the carboxylic acid
protons shows complete imidization. The signal at 2.18 ppm
is due to the three protons of the methyl groups. All aromatic
protons are accountable by the signals between 6.9 and 7.08
ppm. The 13C NMR spectrum (Fig. 4b) show distinct signals
for the methyl and methine carbons at 11.8 ppm and 40 ppm,
respectively.All aromatic carbons appear between 160.8-170.2
ppm.
O
C
+
O
2
H2N R'
NH2
C
O
DMF/52-55 ºC
m-Cresol
O
C
H
H
N
O
C
Preparation of polyaspartimides: The nucleophilic
addition of diamine to bismaleimide (based on aromatic amines
having hetero cyclic ring), the Michael type addition, is a well-
known route to synthesize linear polyaspartimides.
N
R'
C
O
OH
HO
C
O
O
C
(4a)
Acetic anhydride/
sodium acetate
52-55 ºC/6 h
N
O
S
C
O
CH3
O
C
O
O
C
O
N
C
O
C
N
C
R'
N
C
O
R = BANTM
O
Bismaleimide (BMI)
7
6
5
4
3
2
1
0
Scheme-II: Synthesis of bismaleimide
δ ppm
O
C
The structure of the bismaleimide confirmed by FT-IR,
1H NMR and 13C NMR. The representative infrared spectrum
(Fig. 3) of bismaleimide shows a strong absorption at 1715
cm-1 and a weak absorption at 1776 cm-1 due to symmetric
and asymmetric C=O stretching vibrations of the imide ring,
respectively.
(4b)
N
O
S
C
O
CH3
O
C
O
N
C
O
The absence of band in the region 3500-3300 cm-1 show
that the bismaleiamic acid was completely converted into
bismaleimide and the absence of band at 1545 cm-1 due to the
N-H group of amide linkage also confirm the complete ring
formation. The band at 692 cm-1 is due to the C=C bond of the
maleimide ring. The band at 1386 cm-1 is due to the C-N-C
stretching and the band around 3100 cm-1 is due to the =C–H
group of the bismaleimide ring.
160
140
120
100
80
60
40
20
0
δ ppm
Fig. 4. (a) 1H NMR spectrum of BMI-1(MMNPP) (b) 13C NMR of BMI-1

Vol. 25, No. 2 (2013)
Synthesis and Characterization of Thiophene Containing Bismaleimide and Polyaspartimides 1093
The synthesized thiophene containing bismaleimide and
an equivalent amount of aromatic diamine were stirred together
in m-cresol containing a catalytic amount of glacial acetic acid
to promote the polymerization as shown in Scheme-III. The
structure of the polymer was confirmed by FT-IR (Fig. 5).
in Table-1. The inherent viscosity values of polyapartimides
are in the range of 0.40-0.89 dl/g8.
TABLE-1
THERMAL PROPERTIES (N2 atms)/O2 ATMS AND
INHERENT VISCOSITY OF POLYASPARTIMIDES
In N2
T10 %
In air
Char
yield (%)
O
Polymer
code
η
O
Char
yield (%)
T10 %
(ºC)
490
420
-
380
362
390
(dL/g)
Tg
(ºC)
487
469
468
445
396
379
C
C
PAS 3a
PAS3b
PAS 3c
PAS 3d
PAS 4a
PAS 4b
212
242
218
207
186
199
52
51
49
47
46
44
35
36
0.40
0.56
-
0.89
0.58
0.78
+
H N
2
R'
NH
2
N
R
N
C
O
37
35
39
C
O
m
-Cresol
96hrs
100-105oC
O
O
H
N
Thermal properties:The thermal properties of the polymers
were evaluated by DSC and thermogravimetric analysis (TGA)
at a heating rate of 20 ºC/min under nitrogen atmosphere and
are summarized in Table-1, the DSC thermograms of the
polyaspartimides (PAS-3a-4b) are shown in Fig. 6a.
C
H
C
R'
N
H
N
R'
N
C
O
C
O
,
CH
2
R=
PAS-3c
PAS-3d
R'= BANTM
Scheme-III: Synthesis of polyaspartimides
PAS-4b
PAS-4a
PAS-3b
PAS-3a
180
220
Temperature (ºC)
260
100
80
PAS-3a
PAS-4b
PAS-4a
PAS-3d
PAS-3b
PAS-3c
60
40
4000
3000
2000
1500
1000
0500
20
Wavenumber (cm–1
)
Fig. 5. FT-IR Spectra of polyaspartimides
100
300
500
700
Temperature (ºC)
The bands in 3365-3339 cm-1 range are due to N-H
stretching vibration. The disappearance of band at 691 cm-1
due to maleimide C=C bond confirms completion of the addi-
tion reaction of these double bonds. The bands around 1780-
1773 cm-1 and 1720-1709 cm-1 are due to asymmetric and sym-
metric stretching vibrations of the C=O group of the imide
ring respectively. The bands around 1382-1360 cm-1 are due
to C-N-C stretching vibrations of the imide ring. The methyl
group shows the band around 2926-2917 cm-1 due to the C-H
stretching vibrations. The spectroscopic data are well in agree-
ment with the expected structure, ensuring the formation of
polyaspartimides.
Fig. 6. (a) DSC and (b) TGA curve of polyaspartimides
The Tg values of the polymer are in the range of 199-
212 ºC as shown in Table-1, depending on the stiffness of the
polymer chain. The thermograms of the polyaspartimide are
shown in Fig. 6b. All polyaspartimides show a similar pattern
of decomposition and do not show significant weight loss be-
low 350 ºC in nitrogen atmosphere. The 10 % weight loss
temperatures (T10) of PAS (PAS-3a to PAS-4b) are in the
range of 379-487 ºC and the char yield at 800 ºC in nitrogen
atmosphere was found to be in the range of 44-52 %. All the
polyaspartimides are stable upto the temperature of ca. 360 ºC
indicating the high thermal stability of the polyaspartimides9,10
.
Properties of polyasparimides
Conclusion
Inherent viscosity: The inherent viscosity of polyaspar-
timides was determined using Ubbelohde viscometer at a
concentration of 0.5 dl/g in NMP and the results are presented
A new class of thiophene containing BMI were synthe-
sized using the prepared diamine and maleic anhydride. These

1094 Sivasankari et al.
Asian J. Chem.
monomers were characterized by using FT-IR, 1H NMR and
13C NMR. Polyaspartimides were successfully prepared by the
Michael addition reaction of the synthesized bismaleimide with
the various diamines. The polymers were characterized by
using FT-IR. The Tg values of the polyaspartimides are in the
range of 199-212 ºC. The 10 % weight loss temperatures (T10)
of PAS are in the range of 379-487 ºC and the char yield is in
the range of 44-52 % in nitrogen atmosphere. The inherent
viscosity values of polyaspartimides were found to be in the
range of 0.40-0.89 dl/g, which indicates that these materials
can be considered as easily processable polymeric materials.
Thus, this series of polyaspartimides may find use as memb-
ranes for gas separation, as well as in the micro electronics
and composite industries.
REFERENCES
1. M. Kato, T. Shirga, T. Kimura, T. Fukuda, H. Matsuda and H. Nakanishi,
Polym. Adv. Technol., 13, 120 (2002).
2. C.S. Wu, Y.L. Liu and Y.S. Chiu, Polymer, 43, 4277 (2002).
3. Y.L. Liu and S.H. Tsai, Polymer, 43, 5757 (2002).
4. C.S. Wu, Y.L. Liu and Y.S. Chiu, Polymer, 43, 1773 (2002).
5. D.J. Liaw and B.Y. Liaw and J.J. Chen, Polym. J., 42, 867 (2001).
6. F. Shiliang, F.Y.C. Boey and J.M. Abadie, Eur. Polym. J., 44, 2123
(2008).
7. T.Y. Takeichi, T. Sayto, H. Agag and T. Kawauchi, Polymer, 49, 1173
(2008).
8. M. Grigoras, M. Sava, G. Colotin and C.I. Simionescu, J. Appl. Polym.
Sci., 107, 846 (2008).
9. R. Hariharan and M. Sarojadevi, J. Appl. Polym. Sci., 108, 1126 (2008).
10. M. Sava, J. Appl. Polym. Sci., 91, 3806 (2004).
ACKNOWLEDGEMENTS
The authors are grateful to the University Grants Com-
mission, New Delhi, India for the financial support