Research Article Synthesis and Characterization of Novel...

Research ArticleSynthesis and Characterization ofNovel Processable and Flexible Polyimides Containing36-Di(4-carboxyphenyl)pyromellitic Dianhydride

Muhammad Kaleem Khosa1 Muhammad Asghar Jamal1

Rubbia Iqbal1 and Mazhar Hamid2

1 Department of Chemistry Government College University Faisalabad Faisalabad 38000 Pakistan2National Engineering and Scientific Commission PO Box 2801 Islamabad Pakistan

Correspondence should be addressed to Muhammad Kaleem Khosa mkhosapkyahoocom

Received 28 June 2014 Revised 7 August 2014 Accepted 8 August 2014 Published 10 September 2014

Academic Editor Alexandra Munoz-Bonilla

Copyright copy 2014 Muhammad Kaleem Khosa et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

A series of six novel polyimides containing 36-di(4-carboxyphenyl)pyromellitic dianhydride were synthesized via two steps con-densation method Aromatic diamines monomers 4-(4-aminophenoxy)-N-(4-(4-aminophenoxy)benzylidene)-3-chloroaniline(DA1) 4-(4-amino-3-methylphenoxy)-N-(4-(4-amino-3-methylphenoxy)benzylidene)-3-chloroaniline (DA2) 4-(4-amino-2-methylphenoxy)-N-(4-(4-amino-2-methylphenoxy)benzylidene)-3-chloroaniline (DA3) 4-(4-aminophenoxy)-N-(4-(4-amino-phenoxy)benzylidene)-2-methylaniline (DA4) 4-(4-amino-3-methylphenoxy)-N-(4-(4-amino-3-methylphenoxy)benzylidene)-2-methylaniline (DA5) and 4-(4-amino-2-methylphenoxy)-N-(4-(4-amino-2-methylphenoxy)benzylidene)-2-methylaniline(DA6) were prepared and used to synthesize new polyimides by reaction with resynthesized 36-di(4-carboxyphenyl)pyromelliticdianhydride by using two-step condensation method The inherent viscosities of polyimides range from 068ndash104 dL gmminus1 andwere soluble in polar solvents Polyimides have excellent thermal stability by showing 10 weight loss temperature was above450∘C Their glass transition temperatures lie in the range of 250ndash335∘C Wide-angle X-ray diffractometer investigations revealedthe amorphous nature of polyimides Therefore these polymers can be a potential candidate as processable high performancepolymeric materials

1 Introduction

Polyimides are very interesting group of amazingly strongand marvellously heat resistant polymers [1] Aromatic poly-imides have received much attention for half a century dueto their excellent combination of properties and potentialapplications in aerospace microelectronics (flexible printedboards for electronic devices) photoelectronic industry (asphotoresists) and separation industry [2ndash6] Other appli-cations include adhesives and matrix resins for compositesHowever some of their properties like limited solubilityrigid chain characteristics strong chain-chain interactionhigh glass transition and melting temperatures create dif-ficulties in their processing That is why applications ofthese rigid polyimides are restricted in technological and

industrial applications Extensive research has been carriedout to improve their solubility by synthesizing soluble poly-imideswithout disturbing their excellent properties [7ndash15] Inpresent days a number of ways exist to alter chemical struc-ture of synthesizing polymeric materials while maintainingthe excellent level of their thermal andmechanical propertiesSeveral modifications have been made in their chemicalstructure by the introduction of bulky alkyl side substitutionnoncoplanar alicyclic structures flexible aryl or alkyl etherlinkages and asymmetric biphenyl moieties in the back boneof rigid polyimides [16ndash20] By the introduction of flexiblelinkages progress in solubility and significant processabilityhave been achieved by altering crystallinity and intermolec-ular interactions The incorporation of aliphatic segments

Hindawi Publishing CorporationAdvances in ChemistryVolume 2014 Article ID 759594 10 pageshttpdxdoiorg1011552014759594

2 Advances in Chemistry

and noncoplanar structures helps to improve solubility ofpolyimides but is deleterious for thermal and mechanicalproperties To achieve better quality polyimides there is needto design new monomers that is diamines and dianhydridewith structural modifications [21ndash24] Researchers are doingefforts to design and synthesize new diamines and dianhy-dride monomers thus producing a wide range of polyimideswith promising processability and solubility for various tech-nological and industrial applications These efforts make itpossible to synthesize many polyimides which are solubleand easily processable without disturbing their excellentproperties Among these polyimides fluorinated monomershave also gained attention When bulky fluorinated groupsare incorporated soluble polyimides with excellent thermalproperties can be achieved [25ndash28] Asymmetric introduc-tion of bulky substituent or linkages in the backbone of poly-imides is another effective approach to improve the solubilityof polyimides Another approach is the introduction of etherlinkages using a nucleophilic aromatic substitution reactionDue to the presence of flexible moieties on the polyimidebackbone there will be a decrease in rigidity of polymerchain to improve the solubility of polyimides To improve thesolubility of polyimides carboxy groups were also introducedin the backbone of polyimides and were found very helpful inimproving solubility of polyimidesThe carboxy functionalityis desirable in developing new applications such as fabricationof nanostructure by molecular self-assembly ion exchangemembranes polymer electrolytes or ionomers Thus com-ponents into the polyimide main chain are one of the mostsuccessful approaches in attaining solubility without chang-ing their excellent properties These structural modificationsfor monomers have also led to new polyimides with severalimproved properties Consequently it was of interest toinvestigate the thermal stability of aromatic polyimides withvarious linking groups in their backbone The azomethinelinkage is of distinctive significance due to its remarkableproperties such as liquid crystalline property semiconductiv-ity ability to form metal chelates fibre-forming ability finethermal stability and nonlinear optical activity [26ndash29] Avariety of polymers with a Schiff-base structure have beensynthesized characterized and investigated with respect totheir properties [30] Keeping in view the useful propertiesof polyimides thus a diamine monomer containing etherand azomethine linkage has been designed synthesized andexploited to prepare novel poly azomethine imides with goodthermal stability and processability The aromatic diaminescontaining azomethine moiety along with ether linkageswere incorporated in polymer backbone to examine theirstructure-property relationship in terms of inherent viscositysolubility in various solvents thermal stability glass transi-tion temperature and so forth Introduction of azomethinemoiety in the polymer backbonewill incorporate features likesemiconductivity [31] biomedical activity [32] as thermalstabilizers [33] and corrosion inhibition [34ndash36] in the newlysynthesized polymers The monomers and polyimides PI (1ndash6) were characterized by means of elemental analyses FTIR1H-NMR spectroscopy

2 Experimental

21 Materials 4-amino-3-methylphenol 4-amino-2-chloro-phenol 4-fluoronitrobenzene 5-fluoro-2-nitrotoluene2-flu-oro-5-nitrotoluene4-hydroxybenzaldehyde potassium per-manganate tetrakis(triphenylphosphine) palladium p-tol-ylboronic acid sodiumcarbonate dibromodurene hydrazinemonohydrate and pyridine were purchased from E Merckand Aldrich and used without further purification Allorganic solvents dimethyl sulfoxide (DMSO) dimethyl-formamide (DMF) NN-dimethylacetamide (DMAc) N-dimethylpyrolidone (NMP) m-cresol methanol ethanoland toluene were purchased from E Merck Germany andwere dried before used according to the standard methods[37]

22Measurements Melting points were determined by usingcapillary tube on an electrochemical melting point appara-tus model MP-D Mitamura Riken Kogyo Japan and areuncorrected Infrared absorption spectra were recorded asKBr disc on Bio-Rad Excalibur FT-IR Model FTS 3000 MXElemental analysis was performed using a Perkine Elmer2400 CHN elemental analyzerThe 1H spectra were recordedon a BRUKER Spectrometer operating at 300MHz Solventused for analysis was deutrated dimethyl sulfoxide (DMSO-d6) Thermal and DSC analysis were carried out usingPerkin Elmer TGA-7 and DSC 404C Netzsch under nitro-gen atmosphere Wide-angle diffractograms were obtainedusing 304060 XrsquoPert PRO diffractrometer Viscosities wereobtained by usingGilmount falling ball viscometer Solubilitywas determined in different solvents Moisture absorptionvalues were determined by changes in weight of the dried filmbefore and after immersion of water at 25∘C

23 Synthesis of Monomers Six new diamine monomers ie4-(4-aminophenoxy)-N-(4-(4-aminophenoxy) benzylidene)-3-chloroaniline (DA1) 4-(4-amino-3-methylphenoxy)-N-(4-(4-amino-3-methylphenoxy)benzylidene)-3-chloroaniline(DA2) 4-(4-amino-2-methylphenoxy)-N-(4-(4-amino-2-methylphenoxy)benzylidene)-3-chloroaniline (DA3) 4-(4-aminophenoxy)-N-(4-(4-aminophenoxy)benzylidene)-2-methylaniline (DA4) 4-(4-amino-3-methylphenoxy)-N-(4-(4-amino-3-methylphenoxy)benzylidene)-2-methylaniline(DA5) and 4-(4-amino-2-methylphenoxy)-N-(4-(4-amino-2-methylphenoxy)benzylidene)-2-methylaniline (DA6) weresynthesized in three steps as shown in the Scheme 1 Infirst step Schiff bases were prepared by condensation of0025mol of substituted p-hydroxyamines and 0025molof 4-hydroxyaldehyde in dry ethanol (15ndash20mL) in thepresence of acetic acid which act as catalyst After stirringof about 1 h the reaction mixture was refluxed 4-5 hReaction was monitored by thin layer chromatography(TLC) The reaction mixture was filtered and precipitateswere collected The crude product was washed with ethanoland recrystallized with methanol In the second step 1 g ofdihydroxy Schiff base compound was treated with 001mol ofsubstituted 4-fluoronitrobenzene and 001mol of potassium

Advances in Chemistry 3

R1R2

OHH2N OHC

Acetic acidreflux

EtOH

OH

R1 R2

OHHO N CH

R3 R4

NO2FK2CO3DMAc

R1 R2R3R4

N CH

R3 R4

NO2OO2N

NH2-NH2-H2OPd-C

EtOH

O

OO N CH

R3 R4R1 R2R3R4

NH2H2N

+

DA1 R1 Cl R2 H R3 H R4 HDA2 R1 Cl R2 H R3 CH3 R4 HDA3 R1 Cl R2 H R3 H R4 CH3

DA4 R1 H R2 CH3 R4 HDA5 R1 H R2 CH3 R3 H R4 CH3

DA6 R1 H R2 CH3 R3 CH3 R4 H

R3 H

Scheme 1

carbonate in DMAc (60mL) in two necks round bottom flaskunder inert conditions The reaction mixture was heatedat 100∘C for 18ndash20 h The reaction mixture was cooled toroom temperature and poured into water Solid obtained waswashed thoroughly with water and filtered Product obtainedwas recrystallized from ethanol In third step for reduction of

nitro compounds 1 g of above synthesized dinitro compoundwas suspended in 250mL of two-necked flask with 10mLof hydrazine monohydrate and 006 g of 5 palladium oncarbon (Pd-C) and 60mL of dry ethanol The reactionmixture was heated at refluxed for 16 h and then filteredto remove Pd-C Solvent was evaporated through rotary


evaporator and the solid product obtained was recrystallizedfrom ethanol [24]

Data of DA1 Molecular formula C25

H20

N3

O2

Cl meltingpoint 172 plusmn 1 yield 75 elemental analysis calculated(found) C 6977(6975) H 465(463) N 976(97)IR(KBr)cmminus1 3400 3325(ndashNH

2

) 1624(ndashC=N) 1355 (ndashCndashN)1H NMR (DMSO-d

6

120575 ppm) 511 (ndashNH2

) 668ndash780 (m15H aromatic) 865 (s 1H azomethine)


H24

N3

O2


2


6

120575 ppm) 220 (6H CH3

) 545 (ndashNH2

)648ndash768 (m 13H aromatic) 864(s 1H azomethine)


H24

N3

O2


2

) 1618(ndashC=N) 1365 (CndashN)1HNMR (DMSO-d

6

120575 ppm) 214 (s 6H CH3

) 601 (ndashNH2

)661ndash760 (m 13H aromatic) 852 (s 1H azomethine)


H23

N3

O2

meltingpoint 185 plusmn 1 yield 85 elemental analysis calculated(found) C 7628(7619) H 562(560) N 1027(1022)IR(KBr)cmminus1 3443 3365(ndashNH

2

) 1698(ndashC=N)1350 (ndashCndashN)1HNMR (DMSO-d

6

120575 ppm) 212 (s 3H CH3

) 574 (ndashNH2



H27

N3

O2

meltingpoint 160 plusmn 1 yield 80 elemental analysis calculated(found) C 7688(7685) H 617(616) N 961 (960)IR(KBr)cmminus1 3405 3355(ndashNH

2

) 1645(ndashC=N) 1366(ndashCndashN)1HNMR (DMSO-d

6

120575 ppm)206 (s 9H CH3

) 612 (ndashNH2



H27

N3

O2

meltingpoint 160plusmn1 yield 80 elemental analysis calculated(found)C 7688(7684) H 617(612) N 961 (959) IR(KBr)cmminus1 3412 3362(ndashNH

2

) 1645(ndashC=N) 1365(ndashCndashN) 1HNMR(DMSO-d

6

120575 ppm) 210 (s 9H CH3

) 552 (ndashNH2

) 665ndash796(m 13H aromatic) 856 (s 1H azomethine)

24 Synthesis of 423564-Hexamethyl-p-terphenyl Dian-hydride used for the synthesis of polyimides was resyn-thesized by following the reported method [10] A 250mLflask was charged with 467 g (16mmol) dibromodurene100mL toluene 11 g (096mmol) Pd(PPh

3

)4

and 100mL2M Na

2

CO3

solution After addition of 47 g (35mmol) p-tolylboronic acid in 30mL ethanol the mixture was refluxedfor 24 hrs After cooled to room temperature 125mLofH

2

O2

(30) was added with great care under vigorous stirringand the mixture was again stirred for hour After stirringtwo layers were formed in the reaction mixture Separatethe organic layer and dried with MgSO

4

The solvent wasevaporated to obtain crude product which was washed bycold ethanol to remove byproducts and recrystallized from

ethyl acetate Yield 68 mp 282ndash285∘C IR (KBr cmminus1)528 (para-subst oop) 1524(ndashC=C) 1565 1645 1789 1900(para-subst) 2915ndash3045(ndashCH) 1HNMR (DMSO-d

6

ppm)185(s 6H CH

3

) 248(s 12H CH3

) 715ndash730(m 8H Ar)

25 Synthesis of 36-Di(4-carboxyphenyl)pyromellitic Acid A250mL three-necked flask equipped with magnetic stirrerand condenser was charged with 314 g (001mol) of 14-ditolyldurene 120mL of pyridine and 10mL of water Themixture was heated up to 120∘C then added 284 g (018mol)of KMnO

4

portion wise After complete addition of KMnO4

the reaction mixture was further refluxed 12 h This hotreaction mixture was vacuum filtered over a glass funnel toremove MnO

2

After evaporating the filtrate a solid residuewas left behindThat solidwas put into a 250mL three-neckedflask with stirrer and condenser It was treated with 100mL of4 aqueous NaOH solution under agitation After that flaskcontents were heated to 100∘C 948 g (006mol) of KMnO

4

was added and refluxed it for 12 hrs Excess KMnO4

wasremoved using ethanol until the KMnO

4

colour disappearedThen filtered the reaction mixture to remove MnO

2

and thefiltrate was acidified with HCl to get product which wasfurther purified by recrystallization in water Yield 79 IR(KBr cmminus1) 1610(C=C Ar) 1678(ndashC=O) 3550ndash2565(ndashOHacid) 1HNMR (DMSO-d

6

ppm) 724ndash782(m 8H) 131(s 6HCOOH) [10]

26 Synthesis of 36-Di(4-carboxyphenyl)pyromellitic Dianhy-dride A 100mL two-necked flask was charged with whitecrystal of 36-di(4-carboxy)phenylpyromellitic acid (458 g10mmol) and 50mL of acetic anhydride in inert conditionsAfter the reflux of 5 h acetic anhydride was evaporated out toget yellow solids which were further recrystallized from driedDMAc Yield 87 elemental analysis (C

24

H10

O10

) (45833)calculated (found) C 6283(6290) H 218(223) O 34903467 IR (KBr cmminus1) 1675(C=O acid) 1868 and 1775(C=Oanhydride) 3545ndash2550(OndashH acid) 1H NMR (DMSO-d6ppm) 765ndash826(m 8H Ar) 1301(s 2H acid) [10]

27 Synthesis of Polyimide (PI) The synthesized monomerswere subjected to polyimide synthesis polyimides weresynthesized by polycondensation of diamine monomersDA1 DA2 DA3 DA4 DA5 and DA6 with resynthesizeddianhydride monomer 36-di(4-carboxyphenyl)pyromelliticdianhydride [10] Three-necked flask equipped with nitrogeninlet and mechanical stirrer was charged with 12mol ofdiamine in 5ndash10mL of NMP Then 12moL of 36-di(4-carboxyphenyl)pyromellitic dianhydride was added slowly inthe dissolved diamine in NMP The reaction mixture wasstirred for 24 h at room temperature to produce polyamicacid in inert conditionsThe resulting polyamic acid solutionwas converted into polyimides through chemical imidizationand thermal method For chemical imidization in polyamicacid solution equimolar pyridine and acetic anhydride wasaddedThe reactionmixture was stirred at room temperaturefor one hour and then heated at 100∘C for 3 h The resultingsolutionwas poured intomethanol and fibrous precipitates ofpolyimides were collected and dried as shown in Scheme 2


O

O

O

O

O

O

COOH

COOH

NH2H2N

COOH

O

O

O

O

NN

COOH

Ar

Ar

OO N CH

R3 R4R1 R2R3R4

+

Ar

NMP

n

PI1 R1 Cl R2 H R3 H R4 HPI2 R1 Cl R2 H R3 CH3 R4 HPI3 R1 Cl R2 H R3 H R4 CH3

PI4 R1 H R2 CH3 R4 HPI5 R1 H R2 CH3 R3 H R4 CH3

PI6 R1 H R2 CH3 R3 CH3 R4 H

R3 H

Scheme 2


Table 1 FTIR 1H NMR of polyimides (PI-1ndashPI-6)

Compound IR (KBr)cmminus11H NMR (DMSO-d6 120575 ppm)

(s singlet m multiplet)

PI-1 1725 (CO)sym 1788 (CO)asym1665 (C=N)

1301 (s 2H COOH)678ndash790 (m aromatic protons)

865 (s 1H azomethine)















825 (s 1H azomethine)In DMSO-d6 at 295K

For thermal treatment polyamic acid solution was poured inglass petri dishes and placed in oven at 90∘C overnight forfilm preparation Further the film was treated by heating at150∘C for 30min 200∘C for 30min and 280∘C for 1 h [37]

3 Results and Discussion

Six new different polyimides were synthesized by poly-condensation method All the synthesized diamines werecharacterized by IR NMR and elemental analysis FT-IR andNMR spectroscopic techniques confirmed the structures ofdiamines monomers and polyimides

31 IR Spectroscopy FT-IR analysis and spectral data con-firmed the chemical structure of monomers diamines (DA1ndashDA6) and their respective polyimides The data is presentedin Table 1 The presence of imide ring was confirmed bythe characteristic bands at 1788minus1715 cmminus1 for (CO)asym and(CO)sym stretching respectively The dehydration cyclizationof polyamic acid (PAA) to form an imide ring was confirmedby the disappearance of the band at 1690 cmminus1 (related toC=O of amic acid) Further the formation of polyimideswas confirmed by the absence of NndashH vibration at 3500and 3200 cmminus1 Characteristic band at 1627ndash1664 cmminus1 corre-sponding to the azomethine group (ndashCH=Nndash) indicated thepresence of azomethine moiety in polyimides as shown inFigure 1 The disappearance of the amide and carbonyl bandsindicated virtually a complete conversion of the imide ring inthe resulting polyimide [38]

32 1119867 NMR Spectroscopy Formation of diamines and theirrespective polyimides were confirmed by 1H NMR 1HNMR confirmed the reduction of nitro compounds into

3500 2500 1500 500

DA-4

PI-1

PI-2

PI-4

PI-5

Tran

smitt

ance

()

Figure 1 Spectra of DA-4 PI-1 PI-2 PI-4 and PI-5

amines by high field shift of aromatic protons Signals dueto NH

2

protons were found near 511ndash612 Characteristicsignals of C=Nndash at 815ndash866 in spectra of diamines andpolymer confirmed the presence of azomethine moiety Thepeaks between 206 and 220 ppm confirmed the presenceof aliphatic proton structure in the polymer that is methylThe aromatic proton peaks can be observed between 630and 800 ppm regions The characteristic signal of aminogroup disappears in the 1H NMR of polyimides confirm thesynthesis of polyimides and complete imidization [39]


Table 2 Solubility and inherent viscosity of polyimides (PI-1ndashPI-6)

Polyimide DMSO DMAc DMF THF m-cresol H2SO4 120578inn (dLg)PI-1 ++ + + minus + +++ 068PI-2 ++ + minus minus ++ +++ 098PI-3 +++ minus ++ + ++ +++ 101PI-4 ++ + + minus ++ +++ 072PI-5 ++ + + + ++ +++ 094PI-6 +++ + minus + ++ +++ 104+++ = soluble at room temperature ++ = soluble on heating + = slightly soluble on heating minus = insoluble

Table 3 Thermal stability of the polyimides (PI-1ndashPI-6)

Polymer code 119879119892

(∘C) Thermal stability1198795

(∘C)a 11987910

(∘C)b 119879max (∘C)c Char yield ()d

PI-1 250 455 480 500 58PI-2 325 470 498 498 60PI-3 270 498 525 495 65PI-4 280 460 485 525 59PI-5 335 490 515 520 63PI-6 310 498 520 496 64a119879

5

b11987910

temperatures at 5 10 weight loss respectivelycTemperature of maximum decomposition ratedResidual weight when heated to 600∘C in nitrogen

33 Viscosity Measurement Viscosities of all the synthesisedpolyimides were obtained by using Gilmount falling ballviscometer in H

2

SO4

at 30∘C The inherent viscosities of thesynthesized polyimides were calculated between the rangesof 068 and 104 dLg indicated that polymers have moderateto higher molecular weights Most of the polyimides showedhigher value of inherent viscosity than other reported poly-imides having azomethine linkages [40 41]

34 Organosolubility of Polymers Solubility of the synthe-sized polyimides was investigated in different solvents likeDMSO DMAc DMF m-cresol and THF and summarizedin Table 2 Polyimides were found to be soluble in mostof the polar protic solvents The improvement in solubilityis attributed to flexibility induced by incorporated moietiesalong with carboxyl group in polyimide structure whichis related with intermolecular interaction and packing ofpolyimide films Some polyimides were soluble at roomtemperature and some were soluble on heating The etherlinkages along with other aliphatic substitutions like methyland chloro also helpful in increasing solubility of polyimides[10 24]

35Moisture Absorption Thepolyimides were also subjectedto analyse the moisture absorption capacity through changein weight of dried polyimide before and after immersion indistilled water at 25∘C for 24 hrs The moisture absorptionof the polyimides was in the range from 102 to 128 Thatincrease in water uptake of the polymers is might be due tothe incorporation of carboxyl group [10]

36 Thermal Behavior The thermal properties of the syn-thesized polyimides were evaluated by TGA and DSC atheating rate of 10∘C minminus1 The obtained data is summarizedin Table 3Thermal properties of the compounds are stronglydepended on their chemical structure Polyimides showedexcellent thermal properties (Figure 2) They were foundthermally stable up to 480ndash525∘C from the 10 weight loss119879max of ca 495ndash525∘C and char yields of 58ndash65 at 600∘CThe loss of weight in the first degradation step may be dueto the ndashCOOH group So it may be predicted that first stepwas decarboxylation step and showed the decompositionof polyimide backbone Dehydration behaviour of polymerswas also observed by loss of 2-3 of weight This mightbe due to water uptake ability of polyimides Taking intoaccount the results from TGA analysis it was found that thepresented polyimides possess good thermal stability withoutsignificant weight losses up to 380∘C This implies that nothermal decomposition occurs below this temperature andthat the onset decomposition temperature was as high as400∘C for the all polyimidesThe glass transition temperature(119879119892

) of the PIs samples which is one of the key parametersof polymers when considering the high-temperature devicesfabrication and the long-termheat releasing environmentwastaken as themidpoint of the change in slope of the baseline inDSC curves The glass transition temperature 119879

119892

as a secondorder endothermic transition could be considered as the tem-perature at which a polymer undergoes extensive cooperativesegmental motion along the backbone The flexible linkagesdecreased the energy of internal rotation and lowered the119879119892

[42 43] Different intra- and intermolecular interactionsincluding hydrogen bonding electrostatic and ionic forces


100

90

80

70

60

50

200 400 600

PI-1PI-2PI-3

PI-4PI-5PI-6

Wei

ght (

)

Figure 2 TGA curves of polyimides (PI-1 to PI-6)

chain packing efficiency and chain stiffness also affected the119879119892

The 119879119892

of the polyimides (PI-1ndashPI-6) were observed inthe range of 250ndash335∘C depending upon the structure ofdiamine component along with dianhydride and decreasedwith the decreasing of rigidity of the polymer backbone (PI-5) exhibited the highest 119879

119892

(335∘C) owing to the highly rigidpyromellitimide unit along with azomethine backbone withmethyl substituents

37 X-Ray Diffraction X-ray diffraction analysis was alsocarried out for the characterization of polyimides (Figure 3)All the polyimides showed broad peaks in wide-angle X-raydiffraction pattern indicated the amorphous nature of poly-imides It might be due to strong chain interaction betweenthe acid groups which could not help in building regularstructure and disturb chain packing of the polyimides Thestrong interaction among carboxyl group hindered the chainmobility The bulky phenyl groups inside the polymer chainwith ether linkages might have introduced the amorphouscharacteristic in these polyimides The amorphous nature ofpolyimides is responsible for the improvement in solubility ofpolyimides [10 24]

4 Conclusion

Anew series of polyimides were synthesized by condensationmethod of newly synthesized diamines having ether andazomethine linkages with resynthesized dianhydride All thepolyimides were found soluble in most of the polar aproticsolvents and have inherent viscosities in the range of 068ndash104 dLg indicated themoderate to highermolecular weightsof polyimides All the polyimides were found thermally stableupto 498ndash523∘C All the polyimides have amorphous nature

Rela

tive i

nten

sity

10 20 30 40

PI-1

PI-2

PI-3

PI-4

PI-5

PI-6

2120579

Figure 3 X-ray diffraction pattern of polyimides (PI-1 to PI-6)

indicated by the wide-angle X-ray diffraction analysis Onthe basis of such results it is concluded that these polyimidescould be considered for new processable high performancepolymeric materials

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors are grateful to the Higher Education Com-mission of Pakistan for financial support under indigenousscholarship program for PhD [Pin no106-2119-PS6-029]

References

[1] M K Ghosh and K L Mittal Polyimides Fundamentals andApplications Marcel Dekker New York NY USA 1996

[2] C E Sroog ldquoPolyimidesrdquo Journal of Polymer Science Macro-molecular Reviews vol 11 no 1 pp 161ndash208 1976

[3] F Li S Fang J J Ge et al ldquoDiamine architecture effects on glasstransitions relaxation processes and other material propertiesin organo-soluble aromatic polyimide filmsrdquo Polymer vol 40no 16 pp 4571ndash4583 1999

[4] R Rubner ldquoPhotoreactive polymers for electronicsrdquo AdvancedMaterials vol 2 pp 452ndash457 1990

[5] T Fukushima Y Kawakami T Oyama and M Tomoi ldquoPho-tosensitive polyetherimide (Ultem) based on reaction develop-ment patterning (RDP)rdquo Journal of Photopolymer Science andTechnology vol 15 no 2 article 191 2002

[6] T Fukushima T Oyama T Iijima M Tomoi and H ItatanildquoNew concept of positive photosensitive polyimide Reaction


development patterning (RDP)rdquo Journal of Polymer Science APolymer Chemistry vol 39 pp 3451ndash3463 2001

[7] H S Li J G Liu J M Rui L Fan and S Y YangldquoSynthesis and characterization of novel fluorinated aromaticpolyimides derived from 11-bis(4-amino-35-dimethylphenyl)-1-(35-ditrifluoromethylphenyl)-222-trifluoroethane and var-ious aromatic dianhydridesrdquo Journal of Polymer Science APolymer Chemistry vol 44 no 8 pp 2665ndash2674 2006

[8] C P Yang Y Y Su and F Z Hsiao ldquoSynthesis and propertiesof organosoluble polyimides based on 11-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]cyclohexanerdquo Polymer vol 45no 22 pp 7529ndash7538 2004

[9] K H Choi K H Lee and J G C Jung ldquoSynthesis of newpoly(amide imide)s with (n-alkyloxy)phenyloxy side branchesrdquoJournal of Polymer Science Part A Polymer Chemistry vol 39no 21 pp 3818ndash3825 2001

[10] J C Choia H S Kima B H Sohna W C Zina and MReea ldquoSynthesis and characterization of new alkali-solublepolyimides and preparation of alternating multilayer nano-films therefromrdquo Polymer vol 45 no 5 pp 1517ndash1524 2004

[11] T Fukushima KHosokawa TOyama T IijimaM Tomoi andH Itatani ldquoSynthesis and positive-imaging photosensitivity ofsoluble polyimides having pendant carboxyl groupsrdquo Journal ofPolymer Science A Polymer Chemistry vol 39 no 6 pp 934ndash946 2001

[12] M Ueda and T A Nakayama ldquoA new negative-type photosen-sitive polyimide based on poly(hydroxyimide) a cross-linkerand a photoacid generatorrdquoMacromolecules vol 29 no 20 pp6427ndash6431 1996

[13] D J Liaw F C Chang M K Leung M Y Chou andM KlausldquoHigh thermal stability and rigid rod of novel organosolublepolyimides and polyamides based on bulky and noncoplanarnaphthalene-biphenyldiaminerdquo Macromolecules vol 38 pp4024ndash4029 2005

[14] B LiuW Hu TMatsumoto Z Jiang and S J Ando ldquoSynthesisand characterization of organosoluble ditrifluoromethylatedaromatic polyimidesrdquo Journal of Polymer Science Part A Poly-mer Chemistry vol 43 no 14 pp 3018ndash3029 2005

[15] S Tamai A Yamaguchi and M Ohta ldquoMelt processiblepolyimides and their chemical structuresrdquo Polymer vol 37 no16 pp 3683ndash3692 1996

[16] C-P Yang S-H Hsiao and M-F Hsu ldquoOrganosoluble andlight-colored fluorinated polyimides from 441015840-bis(4-amino-2-trifluoromethylphenoxy)biphenyl and aromatic dianhydridesrdquoJournal of Polymer Science A Polymer Chemistry vol 40 no 4pp 524ndash534 2002

[17] C P Yang R S Chen and K H Chen ldquoEffects of diamines andtheir fluorinated groups on the color lightness and preparationof organosoluble aromatic polyimides from22-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]-hexafluoropro-panerdquo Jour-nal of Polymer Science A Polymer Chemistry vol 41 no 7 pp922ndash938 2005

[18] T M Moy C D Deporter and J E McGrath ldquoSynthesisof soluble polyimides and functionalized imide oligomers viasolution imidization of aromatic diester-diacids and aromaticdiaminesrdquo Polymer vol 34 no 4 pp 819ndash824 1993

[19] J Xu C He and T S Chung ldquoSynthesis and characterizationof soluble polyimides derived from [111015840410158401rdquo]terphenyl-2101584051015840-diol and biphenyl-25-diolrdquo Journal of Polymer Science Part APolymer Chemistry vol 39 no 17 pp 2998ndash3007 2001

[20] H B Zhang and Z Y Wang ldquoPolyimides derived from novelunsymmetric dianhydriderdquoMacromolecules vol 33 no 12 pp4310ndash4312 2000

[21] DMHergenrother K AWatson J G Smith JWConnel andR Yokota ldquoPolyimides from 233101584041015840-biphenyltetracarboxylicdianhydride and aromatic diaminesrdquo Polymer vol 43 no 19pp 5077ndash5093 2002

[22] X Z Fang Q X Li Z Wang Z H Yang L X Gao and M XJ Ding ldquoSynthesis and properties of novel polyimides derivedfrom 2233-benzophenonetetracarboxylic dianhydriderdquo Jour-nal of Polymer Science A Polymer Chemistry vol 42 pp 2130ndash2144 2004

[23] S H Hsiao and K H J Lin ldquoPolyimides derived from novelasymmetric ether diaminerdquo Journal of Polymer Science APolymer Chemistry vol 43 pp 331ndash341 2005

[24] Y Shao Y F Li X Zhao X L Wang T Ma and F CYang ldquoSynthesis and properties of fluorinated polyimides froma new unsymmetrical diamine 14-(21015840-Trifluoromethyl-4101584041015840-diaminodiphenoxy)benzenerdquo Journal of Polymer Science Part APolymer Chemistry vol 44 no 23 pp 6836ndash6846 2006

[25] D S Reddy C H Chou C F Shu and G H Lee ldquoSynthesisand characterization of soluble poly(ether imide)s based on221015840-bis(4-aminophenoxy)-991015840-spirobifluorenerdquo Polymer vol44 no 3 pp 557ndash563 2003

[26] G I Rusu A Airinei M Rusu et al ldquoOn the electronic trans-port mechanism in thin films of some new poly(azomethinesulfone)srdquo Acta Materials vol 55 pp 433ndash442 2007

[27] A Zabulica E Perju M Bruma and LMarin ldquoNovel lumines-cent liquid crystalline polyazomethines Synthesis and study ofthermotropic and photoluminescent propertierdquo Liquid Crystalvol 41 no 2 pp 252ndash262 2014

[28] L Marin V Cozan and M Bruma ldquoComparative study ofnew thermotropic polyazomethinesrdquo Polymers for AdvancedTechnologies vol 17 pp 664ndash672 2006

[29] LMarinM Dana and D Damaceanu ldquoNew thermotropic liq-uid crystalline polyazomethines containing luminescent meso-gensrdquo Soft Materials vol 7 pp 1ndash20 2009

[30] CH Li and T C Chang ldquoThermotropic liquid crystalline poly-mer III Synthesis and properties of poly(am ide-azomethine-ester)rdquo Journal of Applied Polymer Science A Polymer Chem-istry vol 29 pp 361ndash367 1991

[31] A Atta ldquoAlternating current conductivity and dielectric proper-ties of newly prepared poly(bis thiourea sulphoxide)rdquo Interna-tional Journal of Polymeric Materials vol 52 no 5 pp 361ndash3722003

[32] J D DrsquoCruz T K Venkatachalam and F M Uckun ldquoNovelthiourea compounds as dual-function microbicidesrdquo Biology ofReproduction vol 63 no 1 pp 196ndash205 2000

[33] M W Sabaa R R Mohamed and A A Yassin ldquoOrganicthermal stabilizers for rigid poly(vinyl chloride) VIII Pheny-lurea and phenylthiourea derivativesrdquo PolymerDegradation andStability vol 81 no 1 pp 37ndash45 2003

[34] I Dehri and M Ozcan ldquoThe effect of temperature on thecorrosion of mild steel in acidic media in the presence of somesulphur-containing organic compoundsrdquo Materials Chemistryand Physics vol 98 pp 316ndash323 2006

[35] M Ozcan I Dehri and M Erbil ldquoOrganic sulphur-containingcompounds as corrosion inhibitors for mild steel in acidicmedia correlation between inhibition efficiency and chemicalstructurerdquo Applied Surface Science vol 236 pp 155ndash164 2004


[36] T K Venkatachalam E Sudbeck and F M Uckun ldquoStructuralinfluence on the solid state intermolecular hydrogen bonding ofsubstituted thioureasrdquo Journal of Molecular Structure vol 751no 1ndash3 pp 41ndash54 2005

[37] D D Perrin W L F Armarego and D R Perrin Drying ofSolvents and Laboratory Chemicals Purification of LaboratoryChemicals Pergamon 2nd edition 1980

[38] S H Hsio C P Yang and S H Chen ldquoSynthesis andproperties of ortho-linked aromatic polyimides based on 12-bis(4-aminophenoxy)-4-tert-butylbenzenerdquo Journal of PolymerScience A Polymer Chemistry vol 38 pp 1551ndash1559 2000

[39] S J Zhang Y F Li X L Wang D X Yin Y Shao and X ZhaoldquoSynthesis and characterization of novel polyimides based onpyridine-containing diaminerdquoChinese Chemical Letters vol 16no 9 pp 1165ndash1168 2005

[40] D L Pavia G M Lampman and G S Kriz Introduction toSpectroscopy Harcourt Brace College San Diego Calif USA1996

[41] H S Hsiao C P Yang and C L Chung ldquoSynthesis andcharacterization of novel fluorinated polyimides based on27-bis(4-amino-2-trifluoromethylphenoxy)naphthalenerdquo Jour-nal of Polymer Science A Polymer Chemistry vol 41 p 20012003

[42] G R Srinivasa S N Narendra Babu C Lakshmi and D CGowda ldquoConventional and microwave assisted hydrogenolysisusing zinc and ammonium formaterdquo Synthetic Communica-tions vol 3 pp 1831ndash1837 2004

[43] H Behniafar and H Ghorbani ldquoNew heat stable and pro-cessable poly(amidendashetherndashimide)s derived from 5-(4-trime-llitimidophenoxy)-1-trimellitimido naphthalene and variousdiaminesrdquo Polymer Degradation and Stability vol 93 no 3 pp608ndash617 2008

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


and noncoplanar structures helps to improve solubility ofpolyimides but is deleterious for thermal and mechanicalproperties To achieve better quality polyimides there is needto design new monomers that is diamines and dianhydridewith structural modifications [21ndash24] Researchers are doingefforts to design and synthesize new diamines and dianhy-dride monomers thus producing a wide range of polyimideswith promising processability and solubility for various tech-nological and industrial applications These efforts make itpossible to synthesize many polyimides which are solubleand easily processable without disturbing their excellentproperties Among these polyimides fluorinated monomershave also gained attention When bulky fluorinated groupsare incorporated soluble polyimides with excellent thermalproperties can be achieved [25ndash28] Asymmetric introduc-tion of bulky substituent or linkages in the backbone of poly-imides is another effective approach to improve the solubilityof polyimides Another approach is the introduction of etherlinkages using a nucleophilic aromatic substitution reactionDue to the presence of flexible moieties on the polyimidebackbone there will be a decrease in rigidity of polymerchain to improve the solubility of polyimides To improve thesolubility of polyimides carboxy groups were also introducedin the backbone of polyimides and were found very helpful inimproving solubility of polyimidesThe carboxy functionalityis desirable in developing new applications such as fabricationof nanostructure by molecular self-assembly ion exchangemembranes polymer electrolytes or ionomers Thus com-ponents into the polyimide main chain are one of the mostsuccessful approaches in attaining solubility without chang-ing their excellent properties These structural modificationsfor monomers have also led to new polyimides with severalimproved properties Consequently it was of interest toinvestigate the thermal stability of aromatic polyimides withvarious linking groups in their backbone The azomethinelinkage is of distinctive significance due to its remarkableproperties such as liquid crystalline property semiconductiv-ity ability to form metal chelates fibre-forming ability finethermal stability and nonlinear optical activity [26ndash29] Avariety of polymers with a Schiff-base structure have beensynthesized characterized and investigated with respect totheir properties [30] Keeping in view the useful propertiesof polyimides thus a diamine monomer containing etherand azomethine linkage has been designed synthesized andexploited to prepare novel poly azomethine imides with goodthermal stability and processability The aromatic diaminescontaining azomethine moiety along with ether linkageswere incorporated in polymer backbone to examine theirstructure-property relationship in terms of inherent viscositysolubility in various solvents thermal stability glass transi-tion temperature and so forth Introduction of azomethinemoiety in the polymer backbonewill incorporate features likesemiconductivity [31] biomedical activity [32] as thermalstabilizers [33] and corrosion inhibition [34ndash36] in the newlysynthesized polymers The monomers and polyimides PI (1ndash6) were characterized by means of elemental analyses FTIR1H-NMR spectroscopy

2 Experimental

21 Materials 4-amino-3-methylphenol 4-amino-2-chloro-phenol 4-fluoronitrobenzene 5-fluoro-2-nitrotoluene2-flu-oro-5-nitrotoluene4-hydroxybenzaldehyde potassium per-manganate tetrakis(triphenylphosphine) palladium p-tol-ylboronic acid sodiumcarbonate dibromodurene hydrazinemonohydrate and pyridine were purchased from E Merckand Aldrich and used without further purification Allorganic solvents dimethyl sulfoxide (DMSO) dimethyl-formamide (DMF) NN-dimethylacetamide (DMAc) N-dimethylpyrolidone (NMP) m-cresol methanol ethanoland toluene were purchased from E Merck Germany andwere dried before used according to the standard methods[37]

22Measurements Melting points were determined by usingcapillary tube on an electrochemical melting point appara-tus model MP-D Mitamura Riken Kogyo Japan and areuncorrected Infrared absorption spectra were recorded asKBr disc on Bio-Rad Excalibur FT-IR Model FTS 3000 MXElemental analysis was performed using a Perkine Elmer2400 CHN elemental analyzerThe 1H spectra were recordedon a BRUKER Spectrometer operating at 300MHz Solventused for analysis was deutrated dimethyl sulfoxide (DMSO-d6) Thermal and DSC analysis were carried out usingPerkin Elmer TGA-7 and DSC 404C Netzsch under nitro-gen atmosphere Wide-angle diffractograms were obtainedusing 304060 XrsquoPert PRO diffractrometer Viscosities wereobtained by usingGilmount falling ball viscometer Solubilitywas determined in different solvents Moisture absorptionvalues were determined by changes in weight of the dried filmbefore and after immersion of water at 25∘C

23 Synthesis of Monomers Six new diamine monomers ie4-(4-aminophenoxy)-N-(4-(4-aminophenoxy) benzylidene)-3-chloroaniline (DA1) 4-(4-amino-3-methylphenoxy)-N-(4-(4-amino-3-methylphenoxy)benzylidene)-3-chloroaniline(DA2) 4-(4-amino-2-methylphenoxy)-N-(4-(4-amino-2-methylphenoxy)benzylidene)-3-chloroaniline (DA3) 4-(4-aminophenoxy)-N-(4-(4-aminophenoxy)benzylidene)-2-methylaniline (DA4) 4-(4-amino-3-methylphenoxy)-N-(4-(4-amino-3-methylphenoxy)benzylidene)-2-methylaniline(DA5) and 4-(4-amino-2-methylphenoxy)-N-(4-(4-amino-2-methylphenoxy)benzylidene)-2-methylaniline (DA6) weresynthesized in three steps as shown in the Scheme 1 Infirst step Schiff bases were prepared by condensation of0025mol of substituted p-hydroxyamines and 0025molof 4-hydroxyaldehyde in dry ethanol (15ndash20mL) in thepresence of acetic acid which act as catalyst After stirringof about 1 h the reaction mixture was refluxed 4-5 hReaction was monitored by thin layer chromatography(TLC) The reaction mixture was filtered and precipitateswere collected The crude product was washed with ethanoland recrystallized with methanol In the second step 1 g ofdihydroxy Schiff base compound was treated with 001mol ofsubstituted 4-fluoronitrobenzene and 001mol of potassium


R1R2

OHH2N OHC

Acetic acidreflux

EtOH

OH

R1 R2

OHHO N CH

R3 R4

NO2FK2CO3DMAc

R1 R2R3R4

N CH

R3 R4

NO2OO2N

NH2-NH2-H2OPd-C

EtOH

O

OO N CH

R3 R4R1 R2R3R4

NH2H2N

+




R3 H

Scheme 1






H20

N3

O2


2


6




H24

N3

O2


2


6

120575 ppm) 220 (6H CH3

) 545 (ndashNH2



H24

N3

O2


2


6

120575 ppm) 214 (s 6H CH3

) 601 (ndashNH2



H23

N3

O2


2


6

120575 ppm) 212 (s 3H CH3

) 574 (ndashNH2



H27

N3

O2


2


6

120575 ppm)206 (s 9H CH3

) 612 (ndashNH2



H27

N3

O2


2


6

120575 ppm) 210 (s 9H CH3

) 552 (ndashNH2



3

)4

and 100mL2M Na

2

CO3


2

O2


4



6

ppm)185(s 6H CH

3

) 248(s 12H CH3



4



2


4



4


2


6



24

H10

O10




O

O

O

O

O

O

COOH

COOH

NH2H2N

COOH

O

O

O

O

NN

COOH

Ar

Ar

OO N CH

R3 R4R1 R2R3R4

+

Ar

NMP

n




R3 H

Scheme 2




























3500 2500 1500 500

DA-4

PI-1

PI-2

PI-4

PI-5

Tran

smitt

ance

()



2








(∘C)a 11987910


PI-1 250 455 480 500 58PI-2 325 470 498 498 60PI-3 270 498 525 495 65PI-4 280 460 485 525 59PI-5 335 490 515 520 63PI-6 310 498 520 496 64a119879

5

b11987910



2

SO4






119892




100

90

80

70

60

50

200 400 600

PI-1PI-2PI-3

PI-4PI-5PI-6

Wei

ght (

)



The 119879119892


119892



4 Conclusion


Rela

tive i

nten

sity

10 20 30 40

PI-1

PI-2

PI-3

PI-4

PI-5

PI-6

2120579





Acknowledgments


References
























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


R1R2

OHH2N OHC

Acetic acidreflux

EtOH

OH

R1 R2

OHHO N CH

R3 R4

NO2FK2CO3DMAc

R1 R2R3R4

N CH

R3 R4

NO2OO2N

NH2-NH2-H2OPd-C

EtOH

O

OO N CH

R3 R4R1 R2R3R4

NH2H2N

+




R3 H

Scheme 1






H20

N3

O2


2


6




H24

N3

O2


2


6

120575 ppm) 220 (6H CH3

) 545 (ndashNH2



H24

N3

O2


2


6

120575 ppm) 214 (s 6H CH3

) 601 (ndashNH2



H23

N3

O2


2


6

120575 ppm) 212 (s 3H CH3

) 574 (ndashNH2



H27

N3

O2


2


6

120575 ppm)206 (s 9H CH3

) 612 (ndashNH2



H27

N3

O2


2


6

120575 ppm) 210 (s 9H CH3

) 552 (ndashNH2



3

)4

and 100mL2M Na

2

CO3


2

O2


4



6

ppm)185(s 6H CH

3

) 248(s 12H CH3



4



2


4



4


2


6



24

H10

O10




O

O

O

O

O

O

COOH

COOH

NH2H2N

COOH

O

O

O

O

NN

COOH

Ar

Ar

OO N CH

R3 R4R1 R2R3R4

+

Ar

NMP

n




R3 H

Scheme 2




























3500 2500 1500 500

DA-4

PI-1

PI-2

PI-4

PI-5

Tran

smitt

ance

()



2








(∘C)a 11987910


PI-1 250 455 480 500 58PI-2 325 470 498 498 60PI-3 270 498 525 495 65PI-4 280 460 485 525 59PI-5 335 490 515 520 63PI-6 310 498 520 496 64a119879

5

b11987910



2

SO4






119892




100

90

80

70

60

50

200 400 600

PI-1PI-2PI-3

PI-4PI-5PI-6

Wei

ght (

)



The 119879119892


119892



4 Conclusion


Rela

tive i

nten

sity

10 20 30 40

PI-1

PI-2

PI-3

PI-4

PI-5

PI-6

2120579





Acknowledgments


References
























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




H20

N3

O2


2


6




H24

N3

O2


2


6

120575 ppm) 220 (6H CH3

) 545 (ndashNH2



H24

N3

O2


2


6

120575 ppm) 214 (s 6H CH3

) 601 (ndashNH2



H23

N3

O2


2


6

120575 ppm) 212 (s 3H CH3

) 574 (ndashNH2



H27

N3

O2


2


6

120575 ppm)206 (s 9H CH3

) 612 (ndashNH2



H27

N3

O2


2


6

120575 ppm) 210 (s 9H CH3

) 552 (ndashNH2



3

)4

and 100mL2M Na

2

CO3


2

O2


4



6

ppm)185(s 6H CH

3

) 248(s 12H CH3



4



2


4



4


2


6



24

H10

O10




O

O

O

O

O

O

COOH

COOH

NH2H2N

COOH

O

O

O

O

NN

COOH

Ar

Ar

OO N CH

R3 R4R1 R2R3R4

+

Ar

NMP

n




R3 H

Scheme 2




























3500 2500 1500 500

DA-4

PI-1

PI-2

PI-4

PI-5

Tran

smitt

ance

()



2








(∘C)a 11987910


PI-1 250 455 480 500 58PI-2 325 470 498 498 60PI-3 270 498 525 495 65PI-4 280 460 485 525 59PI-5 335 490 515 520 63PI-6 310 498 520 496 64a119879

5

b11987910



2

SO4






119892




100

90

80

70

60

50

200 400 600

PI-1PI-2PI-3

PI-4PI-5PI-6

Wei

ght (

)



The 119879119892


119892



4 Conclusion


Rela

tive i

nten

sity

10 20 30 40

PI-1

PI-2

PI-3

PI-4

PI-5

PI-6

2120579





Acknowledgments


References
























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


O

O

O

O

O

O

COOH

COOH

NH2H2N

COOH

O

O

O

O

NN

COOH

Ar

Ar

OO N CH

R3 R4R1 R2R3R4

+

Ar

NMP

n




R3 H

Scheme 2




























3500 2500 1500 500

DA-4

PI-1

PI-2

PI-4

PI-5

Tran

smitt

ance

()



2








(∘C)a 11987910


PI-1 250 455 480 500 58PI-2 325 470 498 498 60PI-3 270 498 525 495 65PI-4 280 460 485 525 59PI-5 335 490 515 520 63PI-6 310 498 520 496 64a119879

5

b11987910



2

SO4






119892




100

90

80

70

60

50

200 400 600

PI-1PI-2PI-3

PI-4PI-5PI-6

Wei

ght (

)



The 119879119892


119892



4 Conclusion


Rela

tive i

nten

sity

10 20 30 40

PI-1

PI-2

PI-3

PI-4

PI-5

PI-6

2120579





Acknowledgments


References
























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




























3500 2500 1500 500

DA-4

PI-1

PI-2

PI-4

PI-5

Tran

smitt

ance

()



2








(∘C)a 11987910


PI-1 250 455 480 500 58PI-2 325 470 498 498 60PI-3 270 498 525 495 65PI-4 280 460 485 525 59PI-5 335 490 515 520 63PI-6 310 498 520 496 64a119879

5

b11987910



2

SO4






119892




100

90

80

70

60

50

200 400 600

PI-1PI-2PI-3

PI-4PI-5PI-6

Wei

ght (

)



The 119879119892


119892



4 Conclusion


Rela

tive i

nten

sity

10 20 30 40

PI-1

PI-2

PI-3

PI-4

PI-5

PI-6

2120579





Acknowledgments


References
























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of







(∘C)a 11987910


PI-1 250 455 480 500 58PI-2 325 470 498 498 60PI-3 270 498 525 495 65PI-4 280 460 485 525 59PI-5 335 490 515 520 63PI-6 310 498 520 496 64a119879

5

b11987910



2

SO4






119892




100

90

80

70

60

50

200 400 600

PI-1PI-2PI-3

PI-4PI-5PI-6

Wei

ght (

)



The 119879119892


119892



4 Conclusion


Rela

tive i

nten

sity

10 20 30 40

PI-1

PI-2

PI-3

PI-4

PI-5

PI-6

2120579





Acknowledgments


References
























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


100

90

80

70

60

50

200 400 600

PI-1PI-2PI-3

PI-4PI-5PI-6

Wei

ght (

)



The 119879119892


119892



4 Conclusion


Rela

tive i

nten

sity

10 20 30 40

PI-1

PI-2

PI-3

PI-4

PI-5

PI-6

2120579





Acknowledgments


References
























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

Research Article Synthesis and Characterization of Novel...

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