research article synthesis and characterization of...

Research ArticleSynthesis and Characterization of New Organosolubleand Thermally Stable Poly(thioether-amide)s Bearing PyridineSubunit in the Main Chain

Esmael Rostami Maryam Bagherzadeh Tahereh Alinassab Maryam MohammadpourMasume Zangooei Mahmood Feraidooni Fatemeh Tavazo and Zahra Keshavarz

Department of Chemistry Payame Noor University PO Box 19395-3697 Tehran Iran

Correspondence should be addressed to Esmael Rostami esmrostamiyahoocom

Received 11 January 2014 Accepted 3 February 2014 Published 27 April 2014

Academic Editors H-L Chen W S Chow and A V Raghu

Copyright copy 2014 Esmael Rostami et alThis is an open access article distributed under theCreative CommonsAttribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

We report the synthesis of new polyamides containing 26-bis(2-thio-2-(4-carboxyphenyl)-1-oxo)pyridine subunit undermicrowave irradiation using Yamasaki phosphorylationmethodThe solubility thermal behavior and viscosity of polyamides wereevaluatedThe structures of polymers have been characterized using IR and 1HNMR spectroscopyThese polyamides showed goodsolubility viscosity high thermal stability and glass transition temperatures Their viscosities and glass transition temperatures arein the range of 063ndash088 and 223ndash295∘C respectivelyThermal stabilities for 10weight loss (T10) are 137ndash173∘C and for 50weightloss (T50) are in the range of 483ndash523∘CThe study of surface morphology showed particle and amorphous structures

1 Introduction

Aromatic polyamides (aramides) explore high thermal sta-bility good chemical resistance excellent mechanical prop-erties and a series of reliable properties that have broadapplications in many areas of research and engineering [1ndash4] However all of these polymers have the main problem ofbeing difficult to process and of fabrication because of theirinfusibility and poor solubility in common organic solventsThe reasons are strong interchain forces and interactionsinherent macromolecular rigidity or crystallinity

There has been an increased attention in the preparationof polyamides with different substituents or structural irreg-ularities to improve their process ability without loweringtheir other desired properties These studies include enteringflexible adducts into the polymer main chain [5ndash7] replacingsymmetrical aromatic rings by unsymmetrical ones [8ndash10]introducing bulky and reliable pendent groups to minimizecrystallization [11ndash15] and forming a noncoplanar and non-symmetrical structure [16ndash18]

Since the first published reports on the use of microwaveirradiation to improve chemical transformations by Gedyeet al in 1986 [19] a large number of research papers have

been published in this active field referred to as microwave-assisted organic synthesis (MAOS) [20 21] Microwaveheating compared to conventional heating procedures indi-cated that it could reduce reaction times increase productyields and enhance product purities by reducing byproductsThe advantages of this efficient technology have also beenexplored in the context of multistep total synthesis [22]medicinal chemistry and drug discovery [23] Also thesemethods were used in a series of fields such as polymersynthesis [24] material sciences [25] nanotechnology [26]and biochemical processes [27] The use of microwaveirradiation in polymer chemistry has thus become such apopular technique that a series of chemists will probably usemicrowave energy to heat chemical reactions on a laboratoryscale to prepare a large number of polymers [28]This efficientmethod of organic synthesis has been used in a large numberof polymer reactions such as step-growth polymerization forthe preparation and synthesis of polyamides [29] polyimides[30] poly(amide-imide)s [31] polyesters [32] polyurea andpolythiourea [33] Also chain growth polymerization undermicrowave (MW) irradiation has been applied for the syn-thesis of a large number of polymers and macromolecules[34]

Hindawi Publishing CorporationISRN Polymer ScienceVolume 2014 Article ID 531754 7 pageshttpdxdoiorg1011552014531754

2 ISRN Polymer Science

NClCl

O

1 2

3

4

N NHHNOO

SS O

OH

O

HO

5

N NH

SH

HNOO

ClCl

3

H2N NH2

+

+

CH3CN

Et3N

CO2HDMFK2CO3

Scheme 1 Synthesis of monomer (5 PDA)

In this study new poly(thioether-amide)s containingpyridine [35] thioether-amide subunits in the main chainwere synthesized undermicrowave irradiation and character-ized It has been demonstrated that they are soluble in a seriesof common organic solvents and showed thermal resistanceSurface morphology of these polymers was studied usingscanning electron microscopy (SEM)

2 Experimental

21 Materials Instruments and Physical Measurements Thereactions for the synthesis of monomer were carried out in anefficient hood All the materials were purchased fromMerckFluka Across Organics and Aldrich chemical companiesN-Methyl-2-pyrrolidinone (NMP Merck) and pyridine (PyMerck) were purified by distillation under reduced pressureover calcium hydride and stored over 4A∘ molecular sievesTriphenyl phosphite (TPP Merck) was purified by fractionaldistillation under vacuum Reagent grade aromatic diamines(Aldrich) including 26-pyridine diamine (PYDA 6) 13-phenylenediamine (PHDA 7) 331015840-diaminodiphenylsulfone(8) and 441015840-diaminodiphenylsulfone (9) were recrystallizedfrom ethanol The melting points (uncorrected) were mea-sured with a Barnstead Electrothermal engineering LTD 9100apparatus Elemental analysis was performed by a CHNndashOndash Rapid Heraeus elemental analyzer FT-IR spectra wererecorded in potassiumbromide pellets on a Bruker apparatusThe 1H NMR and 13C NMR spectra were obtained usingBruker Avance DRX 500MHz apparatus and mass spectrawere obtained with Shimadzu GC-MS-QP 1100 EX modelScanning electron micrograph (SEM) images were obtainedusing a XL30 (Philips) apparatus The MicroSYNTH system

of Milestone which is a multimode platform and is equippedwith a magnetic stirring plate was used for the microwavesynthesis Inherent viscosities (120578inh = ln 120578119903119888 at a con-centration of 05 g dLminus1) were measured with an Ubbelohdesuspended-level viscometer at 30∘C using DMSO as solventThermogravimetric analysis (TGA) was recorded on a V 51ADuPont 2000 system under argon atmosphere at a heatingrate of 10∘C Minminus1 and differential scanning calorimetry(DSC) recorded on a V 4OB DuPont 2000 system underargon atmosphere at a heating rate of 10∘CMinminus1

22 Synthesis of 26-Bis (2-Thio-2-(4-phenylcarboxy)-1-oxo)pyridine (PDA 5) To DMF (30mL) were added 26-bis(2-chloro-1-oxo)pyridine [36] (3 1 mmol 0259 g) K

2CO3

(4mmol 056 g) and thiosalicylic acid (4 2mmol 030 g)at room temperature as shown in Scheme 1 The reactionmixture was stirred at room temperature for 24 h Aftercompletion of the reaction (monitored by TLC) water wasadded and the reaction mixture was neutralized with HClsolution After standing for 2 h the resulting precipitate wasfiltered and recrystallized in ethanol to obtain diacid (5) in94 yield and melting point of 223-224∘C IR (KBr) ] cmminus1was 3356 3078 2898 2363 1697 1646 1446 1146 and 732 1HNMR (500MHz DMSO-d

6) 120575was 399 (s 4H) 722ndash725 (m

2H) 749ndash753 (m 4H) 773ndash778 (m 3H) 992 (dd 119869= 1 8Hz2H) and 1036 (s 2H) ppm13C NMR (125MHz DMSO-d6) 120575 was 16865 16830 15084 14133 14127 13336 13191

12864 12640 12515 11004 and 3705 ppm MS (EI) 119898119911(relative intensity ) was 497 [M]+ (6) 461 (12) 285 (24)150 (73) 109 (100) 82 (76) and 39 (71) Analytical calculationfor C23H19N3O6S2(119872 = 49754) was C 5552 H 385 N

845 and found C 5558 H 381 N 857

ISRN Polymer Science 3

N NHHN

OO

SSDiamines

NMPTPP

MW

NH

AHN

n

N

S

O

O

SO O

O

OH

O

HO

5

N NHHN

OO

SS OO

10 11 12

13

+

6ndash9

10ndash13

( )

PyCaCl2

A =

Scheme 2 Synthesis of polyamides (10ndash13)

23 Synthesis of Polyamides Polyamides were synthesizedthrough the phosphorylation reaction of 26-bis(2-thio-2-(4-phenylcarboxy)-1-oxo)pyridine (5 PDA) with variousdiamines as shown in Scheme 2 A typical example forthe preparation of polyamides is given A mixture of 5

(1mmol 0498 g) 13-phenylenediamine (1mmol 011 g)03 g of CaCl

2 06mL of TPP 05mL of pyridine and 4mL

of NMP was added to the quartz tube and irradiated undermicrowave conditions in 600W for 9Min (3 times 3Min) andfor the rest time of 10Min (2 times 5Min) After cooling to


room temperature the resulting viscose reactionmixture waspoured into 300mL of boiling methanol The resulting crudeproduct was precipitated and then filtered The resultingpolymer was washed with hot methanol (50mL) hot water(twice 50mL) and then hot methanol (50mL) respectivelyand dried under vacuum at 100∘C overnight The yieldswere almost quantitative Spectral data thermal propertiesviscosity and solubility of these polyamides were presentedin the tables and figures

3 Results and Discussion

In this research work we wish to report the synthesisand characterization of polyamides which were obtainedfrom the reaction of a new monomer (5 PDA) contain-ing 26-bis(2-thio-2-(4-phenylcarboxy)-1-oxo)pyridine sub-unit and aromatic diamines under microwave irradiationDichloroamide (3) was readily prepared by using a publishedmethod with some modifications from the reaction of 1 andchloroacetyl chloride [35] Diacidmonomer (5) was preparedby the reaction of 3 and thiosalicylic acid (4) in DMF atroom temperature The IR spectrum of diacid (5 PDA) ispresented in Figure 1 The polymerizations were carried outvia Yamasaki phosphorylation reaction by the reaction ofdiacid (5) and different diamines in the presence of triph-enyl phosphite (TPP) pyridine (Py) N-methylpyrrolidinone(NMP) and calcium chloride (CaCl

2) under microwave

irradiation almost in quantitative yields (Table 1) Polymerswere precipitated in boiling methanol and washed with hotwater and methanol respectively The inherent viscositiesand the yields of polyamides were revealed in Table 1 Theviscosities of polyamides were measured in DMSO at 30∘Cand are in the range of 063ndash088 (Table 1) The structures ofpolymers were fully characterized by their 1H NMR and IRspectra (Table 2) The IR spectrum of polyamide 13 (PPS)appears in Figure 2 and shows good agreement betweenabsorptions and the corresponding structure (Table 2)

The thermal stability of polyamides was studied bythermogravimetric analysis (TGA) and differential scanningcalorimetry (DSC) methods in a wide range of temperatureThe entire polymers showed good thermal stability theresults appear in Table 3 and curves are displayed in Figure 3Glass transition temperature (119879

119892)measurementswere carried

out by use of a differential scanning calorimetry (DSC)and were in the range of 223ndash295∘C The results appear inTable 3 According to the effects of diamine structure onthe thermal behaviour the insertion of a sulfone group intothe diamine structure decreases the overall flexibility of thepolymer chains and increased the 119879

119892value The polymers

containing diamines with no flexible groups (such as 14-and 13-phenylenediamine and 26-pyridinediamine deriva-tives) have high 119879

119892 possibly due to a less flexible polymer

backboneThe thermal stability was measured by thermogravi-

metric analysis (TGA) and shown that polymers are wellthermally stable their decomposition at argon atmospherefor temperature of 10 weight loss 119879 (10) was in the range of137ndash173∘C and the temperature of 50weight loss119879 (50) was

140

120

100

80

60

40

20

0

4000 3500 3000 2500 2000 1500 1000 500

Tran

smitt

ance

()

Wavenumber (cmminus1)

289873

236332

169794

164616

160389

152772

149068

144624

137933

131871

124805

114617

109676

106104

104289

92683

80723

73264

69090

64661

54508

48759

Figure 1 FT-IR spectrum of diacid (5 PDA)

140

120

100

80

60

40

20

0

Tran

smitt

ance

()

4000 3500 3000 2500 2000 1500 1000 500


336665

243306

166398

159343

152667

140021

132009

113873

104370

98822

56002

Figure 2 FT-IR spectrum of polyamide (13 PPS)

Table 1 Inherent viscosity and the yields of polyamides

Polymer Yield () 120578Inh (gdL)a

PPY (10) 94 075PPH (11) 92 063PMS (12) 96 082PPS (13) 98 088aMeasured at a polymer concentration of 05 gdL in DMSO solvent at 30∘C

in the range of 483ndash523∘CThe polymers decomposition tem-peratures for various percent of decomposition and char yieldat 550∘C for all polymers are presented in Table 3 Accordingto the data obtained by thermal stability measurements theincorporation of sulfone units into the polymers backboneenhanced the thermal stability

The solubility behavior of polyamides is investigatedqualitatively in a series of organic solvents such as N-methyl-pyrrolidinone (NMP) NN-dimethylformamide (DMF) tet-rahydrofuran (THF) dimethyl sulfoxide (DMSO) NN-dimethylacetamide (DMAc) and m-cresol and the resultsare summarized in Table 4 All the polymers showed reliablesolubility in polar organic solvents This might be due tothe presence of aromatic and methylene subunits and thedecrease of intermolecular and intramolecular hydrogenbonding Amine amide and thioether units increase theintermolecular and intramolecular hydrogen bonding and


Table 2 Spectral data of polymers

Polymer IR (]cmminus1) 1H NMR (500MHz DMSO-d6) 120575 (ppm)

PPY (10) 3358 3072 2897 2361 1698 1661 1647 1445 1149 and 733469 (s 4H) 741 (d J = 9Hz 2H) 754ndash757 (m 3H)

768ndash772 (m 3H) 793 (d J = 85Hz 2H) 799 (d J = 75Hz2H) 830 (d J = 85Hz 2H) 1042 (s 2H) and 1044 (s 2H)

PPH (11) 3376 3145 2983 2491 1683 and 1115437 (s 4H) 598 (m 1H) 615 (m 2H) 697 (m 1H)

728ndash733 (m 2H) 756ndash762 (m 4H) 778ndash782 (m 3H) 995(dd J = 1 8Hz 2H) 1038 (s 2H) and 1039 (s 2H)

PMS (12) 3481 3363 3224 2983 2431 1698 1667 1622 1595 1137 and1045

399 (s 4H) 685ndash687 (m 2H) 708-709 (m 2H) 718ndash720(m 2H) 728ndash731 (m 2H) 761ndash763 (m 4H) 779ndash781 (m

3H) 993 (dd J = 1 8Hz 2H) 1037 (s 2H) and 1038 (s 2H)

PPS (13) 3366 3281 2985 2433 1663 1593 1138 and 1043

399 (s 4H) 708 (dd J = 25 75Hz 2H) 741ndash743 (m 3H)745ndash747 (m 2H) 768 (d J = 9Hz 2H) 773 (d J = 75Hz

2H) 778-779 (m 2H) 795ndash798 (m 2H) 886 (s 1H) 892 (s1H) 1092 (s 2H) and 1093 (s 2H)

0

20

40

60

80

100

120

0 100 200 300 400 500 600

1011

1213

(W

)

T (∘C)

Figure 3 TGA of polyamides (10ndash13)

Table 3 Thermal properties of polyamides

Polymer 119879119892(∘C) 119879

10

a (∘C) 11987950

b (∘C) Char yieldsc 550∘C ()PPY (10) 234 144 495 38PPH (11) 223 137 483 32PMS (12) 268 173 512 43PPS (13) 295 159 523 47aTemperature of 10 weight loss determined in argon atmospherebTemperature of 50 weight loss determined in argon atmospherecChar yield calculated as the percentage of solid residue after heating fromroom temperature to 550∘C under argon

then increase the crystallinity and close packing On theother hand sulfone units in the aromatic diamines reducethe flexibility and increased close packing and crystallinityAccording to the above discussion therefore the solubilityof polyamides was affected by the several variables andsignificantly the structural variations in diacid monomer (4)and aromatic diamine components can be considered

The surface morphology of polymers has been studiedby scanning electron microscopy using their SEM images

Figure 4 SEM image of polyamide PPY (10)

Table 4 The solubility of polyamides

Polymer NMP DMAc DMF DMSO m-Cresol THFPPY (10) ++ ++ ++ ++ plusmn +PPH (11) ++ ++ ++ ++ + +PMS (12) ++ ++ ++ ++ minus minus

PPS (13) ++ ++ ++ ++ minus minus

(++) soluble at room temperature (+) soluble upon heating (plusmn) partiallysolubleaSolubility measured at a polymer concentration of 005 gmL

(Figures 4 5 6 and 7) According to these images 10 and 13showed particle structure also 11 and 12 showed amorphousstructures

4 Conclusion

In summary we have synthesized and characterized a newset of polyamides based on the pyridine and thiosalicylicacid subunits They were successfully obtained throughthe direct polycondensation reaction of 26-bis(2-thio-2-(4-phenylcarboxy)-1-oxo)pyridine with various diamines viaYamazaki method under microwave irradiation (MW) Thesolubility and thermal stability polymers are high This maybe due to the presence of pyridine and methylene groups inthe presence of the tetrahedral sulfide functional group Thepresence of sulfone group in the diamine subunit increased


Figure 5 SEM image of polyamide PPH (11)

Figure 6 SEM image of polyamide PMS (12)

Figure 7 SEM image of polyamide PPS (13)

glass transition temperature and as a result polymers withhigher symmetric and rigid structures in diamine subunitand as a result in overall polymer backbone showed thehighest thermal stability Thus we afforded polyamides withimproved solubility and high heat resistance The studyof surface morphology of polyamides showed particle andamorphous structures

Conflict of Interests

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

References

[1] S Jamshidi H Yeganeh and S Mehdipour-Ataei ldquoPrepa-ration and properties of one-pack polybenzoxazine-modifiedpolyurethanes with improved thermal stability and electrical

insulating propertiesrdquo Polymer International vol 60 no 1 pp126ndash135 2011

[2] K Faghihi M Ashouri and A Feyzi ldquoSynthesis and character-ization of new polyimideorganoclay nanocomposites contain-ing benzophenone moieties in the main chainrdquo Journal of theMexican Chemical Society vol 57 no 2 pp 133ndash136 2013

[3] D J Yoo S H Hyun A R Kim G G Kumar and K S NahmldquoNovel sulfonated poly(arylene biphenylsulfone ether) copoly-mers containing bisphenylsulfonyl biphenyl moiety structuralthermal electrochemical and morphological characteristicsrdquoPolymer International vol 60 no 1 pp 85ndash92 2011

[4] A-H M El-Aassar ldquoPolyamide thin film composite mem-branes using interfacial polymerization synthesis characteriza-tion and reverse osmosis performance for water desalinationrdquoAustralian Journal of Basic and Applied Sciences vol 6 no 6 pp382ndash391 2012

[5] X Yu X Zhao C Liu et al ldquoSynthesis and properties ofthermoplastic polyimides with ether and ketone moietiesrdquoJournal of Polymer Science A Polymer Chemistry vol 48 no13 pp 2878ndash2884 2010

[6] D Chao L He E B Berda SWang X Jia and CWang ldquoMul-tifunctional hyperbranched polyamide synthesis and proper-tiesrdquo Polymer vol 54 no 13 pp 3223ndash3229 2013

[7] M Ghaemy and M Barghamadi ldquoFluorene-ring-containingdiamine and resultant soluble thermally stable polyamidesrdquoJournal of Applied Polymer Science vol 110 no 3 pp 1730ndash17382008

[8] S H Hsiao C W Chen and G S Liou ldquoNovel aromaticpolyamides bearing pendent diphenylamino or carbazolylgroupsrdquo Journal of Polymer Science A Polymer Chemistry vol42 no 13 pp 3302ndash3313 2004

[9] W Xie G M Geise B D Freeman H-S Lee G Byun andJ E McGrath ldquoPolyamide interfacial composite membranesprepared m-phenylenediamine trimesoyl chloride and a newdisulfonateddiaminerdquo Journal of Membrane Science vol 403-404 pp 152ndash161 2012

[10] R R Pal P S Patil M M Salunkhe N N Maldar andP P Wadgaonkar ldquoSynthesis characterization and constitu-tional isomerism study of new aromatic polyamides containingpendant groups based on asymmetrically substituted meta-phenylene diaminesrdquo European Polymer Journal vol 45 no 3pp 953ndash959 2009

[11] M Ghaemy and M Barghamadi ldquoSynthesis and characteriza-tion of novel photoactive polyamide derived from substitutedfluorene by copper (I) catalystrdquo Journal of Applied PolymerScience vol 114 no 6 pp 3464ndash3471 2009

[12] P Blondin J Bouchard S Beapre M Belletete G Durocherand M Leclerc ldquoMolecular design and characterization ofchromic polyfluorene derivativesrdquo Macromolecules vol 33 no16 pp 5874ndash5879 2000

[13] S-H Chen C-S Shiau L-R Tsai and Y Chen ldquoPoly(99-dihexylfluorene) derivatives containing electron-transportingaromatic triazole segments synthesis optical and electrochem-ical propertiesrdquo Polymer vol 47 no 26 pp 8436ndash8443 2006

[14] D-J Liaw and W-H Chen ldquoSynthesis and characterizationof new soluble cardo poly(amidendashimide)s derived from 22-bis[4-(4-trimellitimidophenoxy)phenyl]norbornanerdquo Polymervol 44 no 14 pp 3865ndash3870 2003

[15] H-J Yen and G-S Liou ldquoNovel thermally stable triarylamine-containing aromatic polyamides bearing anthrylamine chro-mophores for highly efficient green-light-emitting materialsrdquo


Journal of Polymer Science A Polymer Chemistry vol 46 no22 pp 7354ndash7368 2008

[16] M Ghaemy and R Alizadeh ldquoSynthesis characterization andphotophysical properties of organosoluble and thermally stablepolyamides containing pendent N-carbazole grouprdquo Reactiveand Functional Polymers vol 71 no 4 pp 425ndash432 2011

[17] Y-L Liu and S-H Tsai ldquoSynthesis and properties of neworganosoluble aromatic polyamides with cyclic bulky groupscontaining phosphorusrdquo Polymer vol 43 no 21 pp 5757ndash57622002

[18] E Rostami ldquoSynthesis and characterization of new polyamidescontaining pyridine thioetherunits in the main chain undermicrowave irradiation (MW) and their nanostructurerdquo Interna-tional Journal of Polymeric Materials and Polymeric Biomateri-als vol 62 no 3 pp 175ndash180 2013

[19] R Gedye F Smith K Westaway et al ldquoThe use of microwaveovens for rapid organic synthesisrdquo Tetrahedron Letters vol 27no 3 pp 279ndash282 1986

[20] P Lidstrom and J P Tierney EdsMicrowave-Assisted OrganicSynthesis Blackwell Oxford UK 2005

[21] B A Roberts and C R Strauss ldquoToward rapid ldquogreenrdquo pre-dictable microwave-assisted synthesisrdquo Accounts of ChemicalResearch vol 38 no 8 pp 653ndash661 2005

[22] D D Artman A W Grubbs and R M Williams ldquoConciseasymmetric stereocontrolled total synthesis of stephacidins AB and notoamide Brdquo Journal of the American Chemical Societyvol 129 no 19 pp 6336ndash6342 2007

[23] C O Kappe and D Dallinger ldquoThe impact of microwavesynthesis on drug discoveryrdquo Nature Reviews Drug Discoveryvol 5 no 1 pp 51ndash63 2006

[24] R Hoogenboom and U S Schubert ldquoMicrowave-assisted poly-mer synthesis recent developments in a rapidly expanding fieldof researchrdquo Macromolecular Rapid Communications vol 28no 4 pp 368ndash386 2007

[25] J Perelaer B-J de Gans and U S Schubert ldquoInk-jet printingand microwave sintering of conductive silver tracksrdquo AdvancedMaterials vol 18 no 16 pp 2101ndash2104 2006

[26] A Burya O Kuznetsova A Konchits and A Redchuk ldquoTheinfluence of nanocluster carbon materials on the structure andproperties of polyamide nanocompositesrdquo Materials ScienceForum vol 674 no 2 pp 189ndash193 2011

[27] J M Collins and N E Leadbeater ldquoMicrowave energy aversatile tool for the biosciencesrdquo Organic amp BiomolecularChemistry vol 5 no 8 pp 1141ndash1150 2007

[28] T N Glasnov and C O Kappe ldquoMicrowave-assisted synthe-sis under continuous-flow conditionsrdquo Macromolecular RapidCommunications vol 28 no 4 pp 395ndash410 2007

[29] S Mallakpour and M Taghavi ldquoMolten tetrabutylammoniumbromide as eco-friendly media for the synthesis of opticallyactive and thermal stable polyamides under microwave irradi-ationrdquo Polymer Journal vol 40 no 11 pp 1049ndash1059 2008

[30] SMallakpour andZ Rafiee ldquoApplication ofmicrowave-assistedreactions in step-growth polymerization a reviewrdquo IranianPolymer Journal vol 17 no 12 pp 907ndash935 2008

[31] H N Isfahani K Faghihi M Hajibeygi and M BokaeildquoNew optically active poly (amide-imide)s from NN1015840- (bicycle[222] oct-7-ene-2356-tetracarboxylic) bis-l-phenyl alanineand aromatic diamines synthesis and characterizationrdquo Poly-mer Bulletin vol 64 no 7 pp 633ndash646 2010

[32] S Sinnwell and H Ritter ldquoRecent advances in microwave-assisted polymer synthesisrdquo Australian Journal of Chemistryvol 60 no 10 pp 729ndash743 2007

[33] A Banihashemi H Hazarkhani andA Abdolmaleki ldquoEfficientand rapid synthesis of polyureas and polythioureas from thereaction of urea and thiourea with diamines under microwaveirradiationrdquo Journal of Polymer Science A Polymer Chemistryvol 42 no 9 pp 2106ndash2111 2004

[34] C Holtze M Antonietti and K Tauer ldquoUltrafast conversionand molecular weight control through temperature program-ming in microwave-induced miniemulsion polymerizationrdquoMacromolecules vol 39 no 17 pp 5720ndash5728 2006

[35] K R Reddy A V Raghu H M Jeong and S SiddaramaiahldquoSynthesis and characterization of pyridine-based polyure-thanesrdquo Designed Monomers and Polymers vol 12 no 2 pp109ndash118 2009

[36] N I Abdel-Sayed ldquoNovel synthesis of new symmetricalbis-heterocyclic compounds synthesis of bis-thiazolo bis-pyrazolo- bis-benzotriazolo bis-indolo- and bis-pyrazolylthiazolo-26-diamino pyridine derivativesrdquo Bulgarian ChemicalCommunications vol 42 no 1 pp 20ndash26 2010

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Nano

materials


Journal ofNanomaterials


NClCl

O

1 2

3

4

N NHHNOO

SS O

OH

O

HO

5

N NH

SH

HNOO

ClCl

3

H2N NH2

+

+

CH3CN

Et3N

CO2HDMFK2CO3

Scheme 1 Synthesis of monomer (5 PDA)

In this study new poly(thioether-amide)s containingpyridine [35] thioether-amide subunits in the main chainwere synthesized undermicrowave irradiation and character-ized It has been demonstrated that they are soluble in a seriesof common organic solvents and showed thermal resistanceSurface morphology of these polymers was studied usingscanning electron microscopy (SEM)

2 Experimental

21 Materials Instruments and Physical Measurements Thereactions for the synthesis of monomer were carried out in anefficient hood All the materials were purchased fromMerckFluka Across Organics and Aldrich chemical companiesN-Methyl-2-pyrrolidinone (NMP Merck) and pyridine (PyMerck) were purified by distillation under reduced pressureover calcium hydride and stored over 4A∘ molecular sievesTriphenyl phosphite (TPP Merck) was purified by fractionaldistillation under vacuum Reagent grade aromatic diamines(Aldrich) including 26-pyridine diamine (PYDA 6) 13-phenylenediamine (PHDA 7) 331015840-diaminodiphenylsulfone(8) and 441015840-diaminodiphenylsulfone (9) were recrystallizedfrom ethanol The melting points (uncorrected) were mea-sured with a Barnstead Electrothermal engineering LTD 9100apparatus Elemental analysis was performed by a CHNndashOndash Rapid Heraeus elemental analyzer FT-IR spectra wererecorded in potassiumbromide pellets on a Bruker apparatusThe 1H NMR and 13C NMR spectra were obtained usingBruker Avance DRX 500MHz apparatus and mass spectrawere obtained with Shimadzu GC-MS-QP 1100 EX modelScanning electron micrograph (SEM) images were obtainedusing a XL30 (Philips) apparatus The MicroSYNTH system

of Milestone which is a multimode platform and is equippedwith a magnetic stirring plate was used for the microwavesynthesis Inherent viscosities (120578inh = ln 120578119903119888 at a con-centration of 05 g dLminus1) were measured with an Ubbelohdesuspended-level viscometer at 30∘C using DMSO as solventThermogravimetric analysis (TGA) was recorded on a V 51ADuPont 2000 system under argon atmosphere at a heatingrate of 10∘C Minminus1 and differential scanning calorimetry(DSC) recorded on a V 4OB DuPont 2000 system underargon atmosphere at a heating rate of 10∘CMinminus1

22 Synthesis of 26-Bis (2-Thio-2-(4-phenylcarboxy)-1-oxo)pyridine (PDA 5) To DMF (30mL) were added 26-bis(2-chloro-1-oxo)pyridine [36] (3 1 mmol 0259 g) K

2CO3

(4mmol 056 g) and thiosalicylic acid (4 2mmol 030 g)at room temperature as shown in Scheme 1 The reactionmixture was stirred at room temperature for 24 h Aftercompletion of the reaction (monitored by TLC) water wasadded and the reaction mixture was neutralized with HClsolution After standing for 2 h the resulting precipitate wasfiltered and recrystallized in ethanol to obtain diacid (5) in94 yield and melting point of 223-224∘C IR (KBr) ] cmminus1was 3356 3078 2898 2363 1697 1646 1446 1146 and 732 1HNMR (500MHz DMSO-d

6) 120575was 399 (s 4H) 722ndash725 (m

2H) 749ndash753 (m 4H) 773ndash778 (m 3H) 992 (dd 119869= 1 8Hz2H) and 1036 (s 2H) ppm13C NMR (125MHz DMSO-d6) 120575 was 16865 16830 15084 14133 14127 13336 13191

12864 12640 12515 11004 and 3705 ppm MS (EI) 119898119911(relative intensity ) was 497 [M]+ (6) 461 (12) 285 (24)150 (73) 109 (100) 82 (76) and 39 (71) Analytical calculationfor C23H19N3O6S2(119872 = 49754) was C 5552 H 385 N

845 and found C 5558 H 381 N 857


N NHHN

OO

SSDiamines

NMPTPP

MW

NH

AHN

n

N

S

O

O

SO O

O

OH

O

HO

5

N NHHN

OO

SS OO

10 11 12

13

+

6ndash9

10ndash13

( )

PyCaCl2

A =










2) under microwave










140

120

100

80

60

40

20

0

4000 3500 3000 2500 2000 1500 1000 500

Tran

smitt

ance

()


289873

236332

169794

164616

160389

152772

149068

144624

137933

131871

124805

114617

109676

106104

104289

92683

80723

73264

69090

64661

54508

48759


140

120

100

80

60

40

20

0

Tran

smitt

ance

()

4000 3500 3000 2500 2000 1500 1000 500


336665

243306

166398

159343

152667

140021

132009

113873

104370

98822

56002












PPH (11) 3376 3145 2983 2491 1683 and 1115437 (s 4H) 598 (m 1H) 615 (m 2H) 697 (m 1H)


PMS (12) 3481 3363 3224 2983 2431 1698 1667 1622 1595 1137 and1045


3H) 993 (dd J = 1 8Hz 2H) 1037 (s 2H) and 1038 (s 2H)

PPS (13) 3366 3281 2985 2433 1663 1593 1138 and 1043



0

20

40

60

80

100

120

0 100 200 300 400 500 600

1011

1213

(W

)

T (∘C)



Polymer 119879119892(∘C) 119879

10

a (∘C) 11987950










4 Conclusion









References















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




N NHHN

OO

SSDiamines

NMPTPP

MW

NH

AHN

n

N

S

O

O

SO O

O

OH

O

HO

5

N NHHN

OO

SS OO

10 11 12

13

+

6ndash9

10ndash13

( )

PyCaCl2

A =










2) under microwave










140

120

100

80

60

40

20

0

4000 3500 3000 2500 2000 1500 1000 500

Tran

smitt

ance

()


289873

236332

169794

164616

160389

152772

149068

144624

137933

131871

124805

114617

109676

106104

104289

92683

80723

73264

69090

64661

54508

48759


140

120

100

80

60

40

20

0

Tran

smitt

ance

()

4000 3500 3000 2500 2000 1500 1000 500


336665

243306

166398

159343

152667

140021

132009

113873

104370

98822

56002












PPH (11) 3376 3145 2983 2491 1683 and 1115437 (s 4H) 598 (m 1H) 615 (m 2H) 697 (m 1H)


PMS (12) 3481 3363 3224 2983 2431 1698 1667 1622 1595 1137 and1045


3H) 993 (dd J = 1 8Hz 2H) 1037 (s 2H) and 1038 (s 2H)

PPS (13) 3366 3281 2985 2433 1663 1593 1138 and 1043



0

20

40

60

80

100

120

0 100 200 300 400 500 600

1011

1213

(W

)

T (∘C)



Polymer 119879119892(∘C) 119879

10

a (∘C) 11987950










4 Conclusion









References















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials







2) under microwave










140

120

100

80

60

40

20

0

4000 3500 3000 2500 2000 1500 1000 500

Tran

smitt

ance

()


289873

236332

169794

164616

160389

152772

149068

144624

137933

131871

124805

114617

109676

106104

104289

92683

80723

73264

69090

64661

54508

48759


140

120

100

80

60

40

20

0

Tran

smitt

ance

()

4000 3500 3000 2500 2000 1500 1000 500


336665

243306

166398

159343

152667

140021

132009

113873

104370

98822

56002












PPH (11) 3376 3145 2983 2491 1683 and 1115437 (s 4H) 598 (m 1H) 615 (m 2H) 697 (m 1H)


PMS (12) 3481 3363 3224 2983 2431 1698 1667 1622 1595 1137 and1045


3H) 993 (dd J = 1 8Hz 2H) 1037 (s 2H) and 1038 (s 2H)

PPS (13) 3366 3281 2985 2433 1663 1593 1138 and 1043



0

20

40

60

80

100

120

0 100 200 300 400 500 600

1011

1213

(W

)

T (∘C)



Polymer 119879119892(∘C) 119879

10

a (∘C) 11987950










4 Conclusion









References















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials








PPH (11) 3376 3145 2983 2491 1683 and 1115437 (s 4H) 598 (m 1H) 615 (m 2H) 697 (m 1H)


PMS (12) 3481 3363 3224 2983 2431 1698 1667 1622 1595 1137 and1045


3H) 993 (dd J = 1 8Hz 2H) 1037 (s 2H) and 1038 (s 2H)

PPS (13) 3366 3281 2985 2433 1663 1593 1138 and 1043



0

20

40

60

80

100

120

0 100 200 300 400 500 600

1011

1213

(W

)

T (∘C)



Polymer 119879119892(∘C) 119879

10

a (∘C) 11987950










4 Conclusion









References















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










References















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials

































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



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