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  1. 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. 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. 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