1. 36
International Indexed & Refereed Research Journal, ISSN 0974-2832, (Print), E- ISSN- 2320-5474, Aug-Oct, 2013 ( Combind ) VOL –V * ISSUE – 55-57
Introduction:
Aromatic polyamides have attracted much
attention of researchers all over the world as a class of
hightemperatureresistantpolymers.Henceeffortswere
devoted to the synthesis of new, thermally stable poly-
mers. But aromatic polyamides have the poor
processabilityduetotheirlimitedsolubilityincommon
organicsolvents and extremelyhighglass transitionor
melt temperature. Therefore, many efforts have been
made to design the chemical structures with amide
linkage and kinked structure to obtain aramides with
improved processability. [1-4]
Here we report synthesis
andcharacterizationofnewaromaticdiamine;N,N'bis-
(4'-aminobenzoyl)benzene1,3-diamineandnovelpolya-
midestherefrom.Toincreasetheirthermalstabilityand
solubility in common organic solvents, again various
functional groups have been introduced into their
backbones, through further copolymerization.[5-6]
2.ExperimentalAndMethods
N-Methyl-2-pyrrolidone (NMP), N, N-dim-
ethyl acetamide (DMAc) were purified by distillation
underreducedpressureovercalciumhydrideandstored
over molecular sieves 4 Å. Pyridine was refluxed over
potassium hydroxide pellets under nitrogen, distilled
and stored over 4 Å molecular sieves. Terephthaloyl
chloride (TPC) and isophthaloyl chloride (IPC) were
synthesized and purified by reported procedure. 1, 3-
diaminobenzeneand4-nitrobenzoicacidE.Merkprod-
uctwererecrystallizedfromalcoholandvacuumdried.
Research Paper - Chemistry
Aug- Oct , 2013
Synthesis and Characterization ofNew Soluble
Polyamides fromN,N' bis-(4'-aminobenzoyl) benzene1,
3-diaminebyLowTemperatureSolution
PolymerizationMethod
* Satish S.Deokar
*Dept.ofChemistry,S.M.College,Akluj,Dist-Solapur- M.S.
A new aromatic diamine, N,N' bis-(4'-aminobenzoyl) benzene1,3-diamine containing amide group was synthesized and
characterized by FT-IR, NMR (1
H, 13
C, DEPT 13
C) and Mass spectrometry. A series of novel aromatic polyamides was
synthesized from diamine and IPC/TPC in various mole proportions using low temperature solution polycondensation
method. All the polyamides were obtained in very good yields and were characterized by FT-IR spectroscopy, viscosity
measurements, solubility tests, differential scanning calorimetry (DSC), thermogravimeric analysis (TGA) and X-ray
diffraction (XRD) techniques. The inherent viscosities (?inh) of these polyamides were in the range 0.31 to 0.44 dL/g in
DMAc at 30 ± 0.1 °C; indicating moderate to high molecular weight buildup. The polyamides showed solubility in aprotic
polar solvents such as N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), dimethyl sulphoxide (DMSO)
and N,N-dimethylformamide (DMF), pyridine, THF and m-Cresol. The XRD results showed that the polyamides were
partly crystalline. The glass transition temperature (Tg
) of these polyamides were in the range 154 to 207°C. The
thermogravimeric analysis of all polymers showed no weight loss below 300°C whereas the char yields at 800°C were in
the range 18 to 30 % indicating high thermal stabilities of these polymers. Thus these polymers meet high temperature
resistant requirements and could find applications as special materials in aerospace, military and microelectronics
industries. The structure-property correlation among these polyamides is discussed.
A B S T R A C T
Keywords: N, N'bis-(4'-aminobenzoyl) benzene1, 3-diamine, inherent viscosity, XRD, thermal stability.
LiCl was dried under vacuum at 15 °C for 6 hours.
Triphenyl phosphite (Aldrich) was used as received.
2.1SynthesisofN,N'Bis-(4'-nitrobenzoyl)Benzene
1,3-diamine(I)
A 250 mL three necked round bottom flask
equipped with a water condenser, a calcium chloride
guard tube, a magnetic stirrer, a nitrogen gas inlet and
a thermowell was flame dried under flow of nitrogen
gas.N-Methyl-2-pyrrolidone(NMP)50mL,pyridine25
mL,benzene1,3-diamine(MPDA)10g(0.05mol)and
4-nitrobenzoic acid 16.7 g (0.1mol) were charged into
theflask.Triphenylphosphite(TPP)31.26mL(0.12mol)
was added and the reaction mixture was heated to
110°Cunderstirring,for12h.Thereactionmixturewas
then cooled and poured into excess methanol, to pre-
cipitate the N, N'bis-(4'-nitrobenzoyl) benzene1,3-di-
amine which was filtered on Buckner funnel, washed
withhotwaterandthenwithmethanol(3x100mL)and
was dried under vacuum at 80°C.
Yield:23g(90%),M.P.:1870C
2.2SynthesisofN,N'Bis-(4'-aminobenzoyl)Benzene
1,3-diamine(Ii)
Into a 250 mL three necked round bottom flask
N, N'bis-(4'-nitrobenzoyl) benzene1, 3-diamine
(0.020mol,8.12g)and10%Pd/C(0.4g)weresuspended
in200mLethanol.Thesuspensionsolutionwasheated
torefluxand99%hydrazinemonohydrate(20mL)was
added dropwiseover1 h.Afteradditional8hofreflux-
ing,theresultantclear,darksolutionwasfiltered while

2. 37SHODH, SAMIKSHA AUR MULYANKAN
International Indexed & Refereed Research Journal, ISSN 0974-2832, (Print), E- ISSN- 2320-5474, Aug-Oct, 2013 ( Combind ) VOL –V * ISSUE – 55-57
hot to remove catalyst, and the filtrate was subjected
to distillation to remove part of solvent. The concen-
trated solution was poured into 150 mL water with
stirring, giving rise to an off white BABD (II), which
wasfiltered,washedwithwatertillfreefromhydrazine
hydrate. TheBABD(II)was recrystallized fromaque-
ous ethanol and vacuum dried.
Yield:6.5g(93%);M.P.169°C.
2.3 Polymer Synthesis: (Pa-1)
In a 100 mL three-necked round bottomflask
equipped with a magnetic stirrer, a nitrogen gas inlet
and acalciumchlorideguard tubewereplaced BABD,
0.346 g (1mmol) and DMAc, 3 mL and stirred to form
homogenous solution and cooled to -15 °C in ice-salt
bath.TothereactionmixturesolidIPC,0.203g(1mmol)
was added insmall lots over a period of1 hand stirring
wascontinuedforadditional2hat0°Candthenatroom
temperature for 12 h. The viscoussolution was poured
intomethanol,200mLwithrapid stirring.Theprecipi-
tated polymer was filtered, washed with methanol and
driedundervacuumat80°Cfor6h.Yield0.570g(98.5%);
?inh 0.30 dL/g. Other Polyamides, PA-2 to PA-5 were
synthesized by similar procedure.
Scheme: I: Synthesis of N, N' bis-(4'-aminobenzoyl)
benzene1,3-diamine(II)
Scheme: II:SynthesisofPolyamidesfromBABDand
Aromatic polyamides have commercial utility,
because fibers and films of these polymers not only
possessexcellentphysicalpropertiesatroomtempera-
ture but retain their strength and excellent response to
work loading at elevated temperatures for prolonged
period of time. Most of these polyamides are derived
from aromatic diamines by polycondensation tech-
nique.
The structure of monomer was confirmed by
IR, NMR (1
H and 13
C) and mass spectrometry. The
dinitro compound BNBD (I) showed IR band at 1345
cm-1dueto-NO2
groupwhilediaminecompoundBABD
(II) showed band at 3413 and 3320 cm-1 due to -NH2
group which indicates the total conversion of nitro
group into amino group. The PMR spectrum showed
a peak at 3.63 8 corresponding to -NH2
group. All the
polymers were characterised by viscosity measure-
ments,solubility,IR,TGA,DSCandXRDtechniques.
ElementalanalysisofBABD(II)for C,Hand N%was
in good agreement with those calculated.
Aromatic polyamides were synthesized by low-
temperature solution polycondensation of BABD (II)
withisomericaromaticdiacidchlorides,namelyIPCor
TPCinDMAc. Inasimilarmanner,co-polyamideswere
alsopreparedfromBABD(II)andamixtureofIPCand
TPC in different mole proportions(Scheme: 2).
The results of synthesis of polyamides are
presented inTable1.Allthepolymerswereobtained in
more than 96 % yields. These polyamides exhibited
inherentviscositiesintherange0.30to0.44dL/gshow-
ing that the resultant polymers were of moderate mo-
lecular weights. Inherent viscosity of polyamide PA-
5 based on TPC was highest (0.44 dL/g) among the
series. This was attributed to the higher reactivity of
TPC compared to that of IPC.
Theinherentviscosities(ninh)ofthesepolya-
mideswere in therange 0.30-0.44 dL/g in DMAcat 30
±0.1°C;indicatingmoderateto highmolecularweight
build up. The polyamides showed solubility in aprotic
C
O
OHO2N + C
O
HO NO2+
TPP
H2/Pd/C EtOH
NMP/LiCl,Py
NH2H2N
H
N
H
N CC
O O
NO2O2N
(I)
H
N
H
N CC
O O
NH2H2N
(II)
H
N
H
N CC
O O
NH2H2N
H
N Ar NH C
O
C
H
N
O
Ar NH C
O
C
O
X
100-X
Polymer Code :
X : mol % : 100 75 50 25 00
PA 1 PA 2 PA 3 PA 4 PA 5
Ar =
n
+ CCCl Cl
O O
X + (100-X)CC
O O
Cl Cl
-2n HCl DMAc
TPC
IPC
H
N
H
N CC
O O
H
N
H
N
IPC/TPC by low temperature solution polycondensa-
tion
3. Results and Discussion:
Sr.
No
Polymer
Code
mol % Yield
(%)
ηinh
(dL/g)
IPC TPC
1 PA-1 100 00 96 0.30
2 PA-2 75 25 98 0.32
3 PA-3 50 50 97 0.38
4 PA-4 25 75 98 0.33
5 PA-5 00 100 96 0.44
Table-1:%YieldandinherentviscosityofPolyamides
PA-1toPA-5fromBABD(II)andIPC/TPC
Sr. No Polymer

3. 38
International Indexed & Refereed Research Journal, ISSN 0974-2832, (Print), E- ISSN- 2320-5474, Aug-Oct, 2013 ( Combind ) VOL –V * ISSUE – 55-57
polarsolventssuchasN-methyl-2-pyrrolidone(NMP),
N,N-dimethylacetamide(DMAc),dimethylsulphoxide
(DMSO) and N, N-dimethylformamide (DMF), Pyri-
dine,THF and m-Cresol.
Thermal properties of polymers were evalu-
ated by DSC and TGA and the data on these polya-
mides is listed in Table-2. The TGAcurves are shown
infig.1
TheX-raydiffractionpatternofallpolymersexhibited
partly crystalline nature of these materials (Fig.2)
Fig.1TGACurvesofPA-1to PA-5
Fig.2XRDCurvesofPA-1toPA-5
Synthesis of a new diamine containing amide unit,
namelyN,N'bis-(4'-aminobenzoyl)benzene1,3-diamine
BABD (II) was successfully accomplished and it was
characterizedbyIR,NMRandmassspectrometrictech-
niques. A series of polyamides was synthesized by
copolymerization of the BABD (II) and IPC/TPC in
various mole proportions. Viscosity values of these
polymerswereintherangeof0.30to0.44dL/gindicat-
ing built up of moderate molecular weights. The solu-
bilityof polymers was tested in different solvents. The
Tg of polymers were in the range of 154 to 207°C.
ThermalstabilityofpolyamideswasevaluatedbyTGA
undernitrogenatmosphereandallthepolymersshowed
no weight loss below 300 °C; indicating good thermal
stability. The X-ray diffraction pattern of all polymers
exhibited partly crystalline nature of these materials.
4. Conclusions:
[1]. Liou, G. S.; Kakimoto, M. A.; Imai, Y.; J. Polym. Sci. Polym. Chem., 31, 3265 (1993).
[2] Abajo, J. D.; De la campa, J. G.; Lozano A. E.; Macromol. Symp., 199, 293 (2003).
[3] Preston, J.; Encyclopedia of Polymer Science and Technol.; Mark, H. F.; Bikales, N. M.; Overberger, C. G.; Menges, G.,
Eds.; Wiley Interscience, NewYork, 11, 381 (1988).
[4] Lin, J; Sherington, D. C.; Adv. Polym. Sci., 111, 177 (1994).
[5] Volbracht, L.; In Comprehensive Polymer Sci.; Allen G.; Bevington, J.; Eds.; Pergamon, Wheaton and Co.: Exeter, England,
5, 375 (1989).
[6] Yang, H. H.; Aromatic High-Strength Fibers; Wiley Interscience, NewYork, 202 (1989).
Table - 2: Thermal properties of Polyamides PA-1to PA-
5 from BABD (II) and IPC/TPC
R E F E R E N C E
Sr.
No.
Polymer
Code
Ti
(°C)
T10
(°C)
Tmax
(°C )
Residual
wt. at
800°C
( % )
Tg
( °C )
1 PA-1 310 440 530 19 207
2 PA-2 306 455 550 27 188
3 PA-3 302 447 548 30 185
4 PA-4 300 403 499 18 162
5 PA-5 303 435 540 20 154