Preparation and Characterization of Lyotropic Liquid Crystalline Aromatic Copolyamides Containing Twisty and Non-coplanar Moiety

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1 Polymer Journl, Vol. 38, o. 5, pp (2006) Preprtion nd hrcteriztion of Lyotropic Liquid rystlline Aromtic opolymides ontining Twisty nd on-coplnr Moiety Pengto LIU, 1 Qizhen LIAG, 1 heng LIU, 1;2 Xigo JIA, 1;2;y Dingyi G, 3 nd Yng LI 1 1 Deprtment of Polymer Science & Mterils, Dlin University of Technology, Dlin, , P. R. hin 2 Lioning Reserch enter of igh-performnce Resin Engineering nd Technology, Dlin, , P. R. hin 3 Science & Technology Development Division, SIPE, Beijing, , P. R. hin (Received ctoer 27, 2005; Accepted Jnury 17, 2006; Pulished My 15, 2006) ABSTRAT: A series of romtic rigid-chin copolymides were prepred from 1,2-dihydro-2-(4-minophenyl)- 4-[4-(4-(minophenoxyl)phenyl)](2)phthlzin-1-one (DPZ-DA), p-phenylenedimine (PPD), 1,4-is(4-minophenoxy)enzene (BAPB) nd terephthloyl dichloride (TP) y low temperture solution polycondenstion. The polymers were produced with high yields nd reltively high inherent viscosities, rnging from 1.74 to 4.31 dl/g. The introducing of phthlzinone moiety nd ether linkges into the min chin improved the soluility in some polr solvents. The T g vlues of the polymers were in the rnge of nd the 5 nd 10% weight loss tempertures in nitrogen were in the rnge of nd , respectively, indicting their good therml stility. WAXD mesures indicted tht these copolymides were semicrystlline in nture. Most of the polymers exhiited nemtic lyotropic liquid crystlline chrcteristics in concentrted 2 S 4, MP (1 wt % Lil) nd DMAc (1 wt % Lil) solutions, s evidenced y polrizing light microscopy. [doi: /polymj ] KEY WRDS Lyotropic Liquid rystlline / opolymides / Phthlzinone / emtic / Since the discovery of liquid crystlline, nisotropic ordering ehviors of liquid crystls (Ls) hve een of considerle interest to cdeme nd industry. 1 4 Liquid crystlline polymers (LPs) cn e found in numer of commercil pplictions rnging from high strength engineering plstics to opticl disply devices. Polymers tht exhiit liquid crystllinity, either in the melt or in their solutions, usully consist of comprtively rigid structures tht confer high extension on the moleculr chins. 3 6 The structure of rigid chin polymers lwys contins romtic rings together with functionl groups, hydrogen onding, nd moleculr symmetry. These structurl fctors, promoting strong intermoleculr interction nd hence liquid crystllinity, unvoidly led to high melting tempertures nd poor soluility of the resulting polymers which prevent their process or use in mny pplictions. For exmple, poly(p-phenylene terephthlmide) (PPTA) which is the chemicl structure of Kevlr Ò is lyotropic LP nd exhiits outstnding mechnicl properties, good therml stility, nd excellent chemicl resistnce, ut this polymide fier cn only e spinned from its conc. 2 S 4 solution. 7 In n ttempt to improve the soluility of rigid chin liquid crystlline polymers especilly PPTA, mny efforts hve een mde to modify the polymer chin structure. Some of these pproches include the incorportion of twist nd non-plnr moiety nd flexile links into the polymer chin It hs een found tht romtic polymides contining phthlzinone moiety nd ether linkges in the polymer ckone exhiit excellent properties including eing solule in some polr protic solvents such s MP, DMAc etc But studying of the liquid crystlline ehvior of these polymides is only t the eginning. It hs een demonstrted tht one of the prerequisites for polymer to exhiit liquid crystllinity is the strightness nd rigidity of the polymer chin, which cn e relted to persistence length Flory predicted tht for rigid rod polymer chin to exhiit liquid crystllinity, the spect rtio of the rodlike molecule should e lrger thn It will e interesting to see rigid chin polymers contining high percentge of twist non-plnr moiety nd ether linkges still exhiiting liquid crystllinity. In the present rticle, 1,2-dihydro-2-(4-minophen- yl)-4-[4-(4-(minophenoxyl)phenyl)](2)phthlzin- 1-one (DPZ-DA) nd 1,4-is(4-minophenoxy)enzene (BAPB) were introduced into the min chin of PPTA y low temperture solution polymeriztion method. 18 Thus series of copolymides contining vrying rtios of twist non-plnr moiety nd ether linkges were otined. The ility of the polymers to form L solutions ws tested. The structures of the copolymides were chrcterized nd their inherent viscosity, soluility, therml properties, nd crystllinity were lso investigted. y To whom correspondence should e ddressed (Tel: , Fx: , E-mil: xgjin@chem.dlut.edu.cn). 477

2 P. LIU et l. EXPERIMETAL Mterils 1,2-Dihydro-2-(4-minophenyl)-4-[4-(4-(minophenoxyl)phenyl)](2)phthlzin-1-one (DPZ-DA, mp: ) ws prepred ccording to the reported method. 11 p-phenylenedimine (PPD) ws purified y vcuum sulimtion. 1,4-Bis(4-minophenoxy)- enzene (BAPB, mp: ) ws prepred y the romtic sustitution rection of hydroquinone nd p-chloronitroenzene nd y the susequent reduction of the intermedite is(p-nitrophenoxy) compound. 19 Terephthloyl dichloride (TP) ws purified y vcuum distilltion. Regent grde Lil ws dried under vcuum t 180 just efore use. -methyl-2- pyrrolidone (MP) ws purified y distilltion under reduced pressure over 2 nd stored over 4 Å moleculr sieves. Pyridine (Py) ws refluxed over K pellets nd distilled. Polymer Synthesis The copolymide contining 10 mol % DPZ-DA, 30 mol % BAPB nd 60 mol % PPD is nominted s P nd the other denomintion of the polymers re the sme. A typicl exmple of the synthesis of P is shown s follows. A mixture of g (1.0 mmol) DPZ-DA, g (3.0 mmol) BAPB, g (6.0 mmol) PPD nd 0.40 g Lil were chrged into three-neck flsk contining 30 ml MP nd 1.0 ml Py t 0. After ll the dimines nd slt were dissolved, g (10.0 mmol) TP were dded into the mixture. Then the system were mintined with stirring under 2 tmosphere for out 6 h t 0. The resulting copolymide ws crushed nd poured into 400 ml ethnol/wter (1:1, v/v). The ple yellow mssive copolymer ws wshed thoroughly with hot wter nd dried then extrcted with cetone for 8 h nd dried under vcuum overnight t 100. The yield ws 99%. Anl. clcd for P :, 72.50%;, 4.1%;, 9.49%. Found:, 70.52%;, 4.23%;, 9.30%. Mesurements Inherent viscosities ( inh ) were mesured y Uelohde viscometer t concentrtion of 0.5 g/dl. FT-IR spectr were recorded y reflection method with Thermo icolet exus 470 Fourier trnsform infrred (FT-IR) spectrometer. 1 MR spectr were otined using Vrin IVA 400M nucler mgnetic resonnce. Elementl nlysis ws performed on rld Er1106 elementl nlyzer. Differentil scnning clorimetry (DS) nlysis nd thermogrvimetric nlysis (TGA) were performed on etzsch 204 DS nd stzsch 209 TG instruments, respectively. All smples were tested in flowing 2 t heting rte of 20 /min. The wide-ngle X-ry diffrction (WAXD) mesurements were performed on Rigku D/mx 2400 utomtic X-ry diffrctometer using i-filtered u K rdition (40 V, 100 ma) t room temperture. The rotted velocity of the goniometry ws 4 /min. Tensile properties of the thin polymer film specimens (out 8 mm wide nd 60 mm long) were evluted t room temperture on Shimdzu AG-2000A tester nd the extension rte ws 100 mm/min. The textures of the copolymides were identified with n lympus B-2 polrizing light microscope (PLM). RESULTS AD DISUSSI Polymer Synthesis Although Ymzki-igshi phosphoryltion method strting from dicroxylic cid nd dimine is the widely used procedure in the lortory, it is difficult to get high moleculr weight polymide The low temperture solution polycondenstion of dicidchloride with dimines is convenient method for the preprtion of high moleculr weight polymide. The synthesis route is shown in Scheme 1. By chng DPZ-DA BAPB PPD l l MP/Py/Lil * TP Scheme 1. The synthesis route of the copolymides. 478 Polym. J., Vol. 38, o. 5, 2006

3 Preprtion of Lyotropic Liquid rystlline opolymides ing the molr rtios of the dimines nd optimizing the rection prmeters, we hve successfully got series of novel copolymides with the inherent viscosity ( inh ) vlues rnged from 1.74 to 4.31 dl/g mesured in MP (1 wt % Lil) or conc. sulfuric cid ccording to their soluilities. vious rod climing phenomen nd stir oplescence were oserved during the strting period of polymeriztion. When the percentges of PPD were more thn 60%, such s P nd P , the rection systems chnged into gel stte quickly, the dry of the solutions ppered, nd the polymers were splitted into smll prticles with the intensively stirring within 20 min. When the percentges of PPD were in the rnge of 40 60%, the polymer were in jelly stte nd did not drop when they were ttched to the wll of the flsk, so just sttic plcing ws needed in the lter rection process nd the color of these products were ple yellow. While the percentges of PPD were less thn 40%, such s P nd P , the systems were very viscous liquid nd stirring could go on until the rection ws stopped nd the polymers were white (Tle I). The structures of these resulting copolymides were chrcterized y FT-IR nd 1 MR. The representtive FT-IR spectr of the polymers re shown in Figure 1. It showed the chrcteristic sorption nds ner 3300 cm 1 due to stretch, 1653 cm 1 due to = stretch, 1600 cm 1 due to = stretch, 1516 cm 1 due to comined end nd stretch, 1248 cm 1 due to Ph Ph stretch nd 1112 cm 1 due to stretch. The representtive 1 MR spectrum of P is shown s Figure 2. In the spectrum the resonnce of proton ppered t opolymer Tle I. inh (dl/g) Physicl properties nd soluility of the copolymides olor MP MP /Lil d Soluility c DMAc DMAc /Lil d onc. 2 S 4 P Yellow þ þ þ P Yellow þ þ þ þ P Yellow þ þ þ þ þ P Yellow þ þ þ þ þ P Yellow þ þ þ þ þ P White þ e þ þ þ þ P Yellow þ þ þ þ þ P Yellow þ þ þ þ þ P Yellow þ þ þ þ þ P White þ e þ þ þ þ determined t concentrtion of 0.5 g/dl in MP (1 wt % Lil) t 25. determined t concentrtion of 0.5 g/dl in concentrted sulfuric cid t 25. c Tested with 0.02 g of the polymers in 1 ml of solvent: þ: solule t room temperture; þ : prtilly solule; : insolule. d Solvent contining 1 wt % Lil. e Good films were csted from their MP solutions. The tensile strength, initil modulus, nd rek elongtion for P film were Mp, 2.18 Gp, nd 6.2%; for P film were Mp, 2.42 Gp, nd 6.7%, respsctively. the chemicl shift of ppm nd the resonnce of of romtic rings ppered t ppm. The pek t 8.46 ppm corresponded to the protons which is specil shift of phthlzinone. The rtio of integrl re of the peks of : : (except ) ws 5.08:1:38.79 which in very ner the theoreticl rtio of 5:1:39. Therefore the structure of the otined copolymer ws coincident with our design. P P P P Wvenumers (cm -1 ) Figure 1. FT-IR spectr of copolymides. Polym. J., Vol. 38, o. 5,

4 P. LIU et l Figure 2. 1 MR spectrum of P Polymer Soluility The soluility of the copolymides ws qulittively tested in some typicl orgnic solvents, nd the results re reported in Tle I. They showed improved soluility with the content of phthlzinone moieties nd ether linkges increse, which ws coincide with the phenomenon of polymeriztion. The more percentges of PPD in the ction systems resulted in poor soluility nd thus the time of homogeneous rection ws shortened. This is ttriute to the fct tht twist nd non-coplnr phthlzinone moiety nd ether linkges reduce the tight pcking of the polymer chins nd do not llow the mcromolecules to pck closely through hydrogen onds etween mides groups, thus they fcilitte the penetrtion of the smll molecules of solvent into the polymer chins. Almost ll the polymers were solule in MP or DMAc oth contining few Lil. When the rtio of PPD is less thn 40%, the polymers were solule in MP. These mke it possile for the polymers to form lyotropic L in the polr solvents nd to pply in spinning or csting processes. Therml Properties To study the therml ehvior of the polymers, differentil scnning clorimetry (DS) test ws performed etween in flowing 2 t heting rte of 20 /min. o trnsition due to softening or melting ws oserved. The glss trnsition tempertures (T g, tken s the midpoint of the chnge in slope of the seline) of polymides were found in the rnge of nd the otined results re collected in Tle II. The therml decomposition tempertures of the polymers were evluted y mens of thermogrvimetric nlysis (TGA) nd derivtive thermogrvimetric (DTG) nlysis t heting rte of 20 / min in flowing 2. All of these polymers showed similr decomposition ehvior nd the representtive curves re shown in Figure 3. Most of the polymers showed no significnt weight loss up to 400. But there were more ether linkges in P nd P which were esy to decomposition, the initil weight loss temperture ws low. The tempertures Tle II. opolymer Therml properties of the copolymides T g T 5% T 10% T mx y ( ) ( ) ( ) c ( ) d (%) f P g P P P , 562 e 53 P P P P , 570 e 60 P , 573 e 55 P From DS mesurements conducted t rte of 20 /min in nitrogen. Temperture for 5% weight loss in 2, heting rte of 20 /min. c Temperture for 10% weight loss in 2, heting rte of 20 /min. d Temperture for the mximum in 2, heting rte of 20 /min. e Two peks in the DTG curves. f hr yield clculted s the percentge of solid residue fter heting from 200 to 800 in 2. g not detected. for 10% grvimetric loss (T 10% ), which re importnt evidence for therml stility, were in the rnge of The tempertures for 5% weight loss (T 5% ) nd for the mximum weight loss rte (T mx ) were in the rnge of nd , respectively. In ddition, chr yield ( y ) t 800 for the polymers were out 53 62% (Tle II). These resultnt dt suggested tht the introduction of the romtic heterocyclic phthlzinone moiety into the polymer ckone retins the excellent therml stility of Kevlr. Polymer rystllinity The crystllinity of the copolymides ws exmined y wide ngle X-ry diffrctions otined on slice smples. All of the polymers exhiited morphous ptterns efore eing nneled. As shown in Figure 4, the representtive polymides exhiited rod dispersive peks of diffrction t round 2 ¼ 20{22. This oservtion is quite resonle ecuse the presence of twist non-coplnr conformtion of the phthlzinone moiety decrese the intermoleculr force e- 480 Polym. J., Vol. 38, o. 5, 2006

5 Preprtion of Lyotropic Liquid rystlline opolymides Weight (wt%) TGA DTG. P P Temperture ( o ) Deriv. weight (wt%/ o ) Reltive Intensity P P P P Thet [deg.] Weight (wt%) TGA DTG. P P Temperture ( o ) tween the polymer chins, susequently cuse decrese in crystllinity. owever, when the smples were heted up to 360, which is slightly ove their T g s, nd kept t this temperture for 2 h, the polymer chins could receive enough energy to overcome the hindrnce nd rerrnge in the more regulr form. Then the smples were cooled grdully nd the rerrnged min chin structures were remined, which imprted the smples with the semicrystlline chrcter. As shown in Figure 5, severl ovious diffrction 0.0 Deriv. weight (wt%/ o ) Figure 3. TGA ( ) nd DTG ( ) curves of copolymides in nitrogen, heting rte of 20 /min. Reltive Intensity Figure 4. nneled. P P P P Thet [deg.] X-Ry diffrction ptterns of copolymides efore Figure 5. nneled. X-Ry diffrction ptterns of copolymides fter peks in their X-ry diffrction pttern were oserved fter eing nneled. The ngle peks of the spectrum were t 2 ¼ 20{23 corresponding to the intermoleculr lyer thickness of Å. Additionlly, when the percentges of PPD decresed from 60 to 20%, the thickness incresed from 4:05 to 4:35 Å. These dt lso indicte tht the kink non-plnr phthlzinone moiety nd ether linkges in the polymer chins increse the disordered stte nd thus increse the distnce of the polymer chins. Lyotropic Behvior For the formtion nd exmintion of prospective lyotropic systems, the polymers re dissolved in conc. 2 S 4, MP (1 wt % Lil), DMAc (1 wt % Lil) or pure MP, respectively, to form clss of solutions with different concentrtion in the rnge of 4 30 wt %. oncentrtions higher thn 30 wt % were not investigted since the polymers were not solule thoroughly in the system. Then the homogeneous polymer solutions were plced on glss slide nd covered with cover glss nd oserved on polrizing light microscope (PLM) under crossed polrizer. The criticl concentrtion vlues in different solvents t room temperture re listed in Tle III. Most of these copolymides formed nisotropic phse in their conc. 2 S 4, MP (1 wt % Lil) nd DMAc (1 wt % Lil) solutions, with vlues in the rnge of 20 28, 5 16 nd 4 13 wt %, respectively. The of different copolymer in the sme solvent vried evidently. With the molr rtio of PPD in the dimines decresed, the density of hydrogen onds etween interchins decresed nd the polymer chin ecme disorder ecuse of the twisted non-coplnr phthlzinone structure nd flexile ether linkges. So it needed higher concentrtion to form L nd thus the incresed. Tle III lso shown tht the vlues in MP/Lil or DMAc/Lil re lower thn the corresponding vlues in conc. 2 S 4. This cn e understood s ex- Polym. J., Vol. 38, o. 5,

P. LIU et l. Tle III. opolymer riticl concentrtion vlues of the copolymides onc.

8 7 6 P-404020 16 14 13 The criticl concentrtion (wt %) vlues t which the lyotropic phse ppers t room temperture. ot determined for the limited soluility.

plined y Ahroni tht the onset of nisotropy nd ttinment of full nisotropy re dependent on the mgnitude nd sign of the polymer solvent interction prmeter, 22 the smller the interction prmeter, the

Droplet texture, threded texture, schlieren texture nd mrled texture cn e seprted from these photos, which re the typicl texture of nemtic liquid crystls.

6 P. LIU et l. Tle III. opolymer riticl concentrtion vlues of the copolymides onc. 2 S 4 (wt %) MP /1% wt Lil MP DMAc /1% wt Lil P D D P D P D 5 P D 4 P D 5 P c P D 6 P D 6 P P The criticl concentrtion (wt %) vlues t which the lyotropic phse ppers t room temperture. ot determined for the limited soluility. c Lyotropic phse ws not ville under the test condition. plined y Ahroni tht the onset of nisotropy nd ttinment of full nisotropy re dependent on the mgnitude nd sign of the polymer solvent interction prmeter, 22 the smller the interction prmeter, the lower the vlues of the criticl concentrtions. As representtive exmples, four photogrphs of different copolymides in different solutions t room temperture re shown in Figure 6. Droplet texture, threded texture, schlieren texture nd mrled texture cn e seprted from these photos, which re the typicl texture of nemtic liquid crystls. It is exciting to discover tht polymide contining twist nd non-plnr moiety nd ether linkges in the polymer ckone lso exhiit lyotropic liquid crystllinity. The formtion of the liquid crystlline solutions of romtic polymides is complex nd influenced y comintion of fctors. 15,16 In solution the polymide chins must hve n extended rigid chin chrcter including trns configurtion of the mide linkges. The soluility must e sufficiently high to exceed the criticl concentrtion t which the formtion of iphsic solution (liquid crystlline phse coexisting with isotropic phse) occurs. Soluility nd chin stiffness re ffected y polymer structure, polymer solvent interctions, ggregtion, moleculr weight, nd temperture. Although the introduction of phthlzinone moiety nd ether linkges destroy the tightness of the polymer chins, it improved the soluility nd polymer polr solvent interction oviously nd it is possile to form lyotropic phse in polr orgnic solvent. When the solutions were plced under PLM with hot stge, we could oserve tht the vlues were grdully incresed with the temperture. Tke P in MP/Lil solution for exmple, the vlue t room temperture (20 ) ws 5% nd when the temperture is 180, the vlue incresed to 8.1%. A B D Figure 6. pticl microgrphs of copolymide solutions (mgnifiction 40): (A) P t 9 wt % in MP/Lil (1% w/v) solution (droplet texture); (B) P t 8 wt % in DMAc/Lil (1% w/v) solution (schlieren texture); () P t 16 wt % in MP (threded texture); (D) P t 25 wt % in conc. 2 S 4 (mrled texture). 482 Polym. J., Vol. 38, o. 5, 2006

7 Preprtion of Lyotropic Liquid rystlline opolymides Temperture ( o ) Isotropic L+I Liquid rystl essing nd pplictions such s dry-wet spinning of fiers or the preprtion of films, memrnes nd cotings. Acknowledgment. The uthors cknowledge with gret plesure the finncil support provided y the tionl igh Technology Reserch nd Development Progrm of hin (863, o. 2003AA33G030) nd SIPE oncentrtion (wt%) REFEREES Figure 7. Phse digrm derived from opticl microscopy of P in MP/Lil (1% w/v) solution; The lower curve is the ppernce of isotropic inclusions in the L phse nd the upper curve is the disppernce of the irefringence t the nemtic isotropic trnsition tempertures. The temperture-concentrtion ehvior of the solutions ws lso oserved. When glss slide with solution ws plced on hot stge etween crossed polr, irefringent (right) nemtic texture ws ppered. Upon heting, the L texture melted nd drk res corresponding to the isotropic phse ppered. ontinued heting incresed the size of drk res until they finlly colesced to give completely isotropic field of view t temperture T I, which we defined s the nemtic isotropic trnsition temperture. The representtive phse digrm of P in MP/ Lil (1% w/v) solution is shown s Figure 7 nd ll the other copolymers hd the similr digrm in different solutions. LUSIS A series of romtic copolymides contining phthlzinone moiety nd ether linkges were synthesized. The polymers exhiit improved soluility in polr protic solvents with or without the ddition of Lil ecuse the introduction of twisted non-coplnr phthlzinone moiety nd flexile linkges. The polymers possessed high T g vlues nd excellent therml stility. WAXD mesures indicted tht the polymers were semicrystlline fter eing nneled. servtions under PLM demonstrted tht the texture of the polymers solutions were nemtic lyotropic liquid crystlline in conc. 2 S 4, MP (1 wt % Lil) nd DMAc (1 wt % Lil). The polymides with excellent properties mde it possile for the different proc- 1. A. A. ollyer, Liquid rystlline Polymers: From Structures to Applictions, Elsevier Science, London nd ew York, 1992, chpt. 1 2, p L. S. Prk, D.. Lee, Y. S. Kil, nd T.. Ahn, J. Appl. Polym. Sci., 69, 1517 (1998). 3. T. S. hung, Polym. Eng. Sci., 26, 901 (1986). 4. K. Rmeshu nd P. Knnn, Liq. ryst., 31, 843 (2004). 5. R. i, J. Preston, nd E. T. Smulski, Mcromolecules, 25, 563 (1992). 6. S. M. Ahroni, Mcromolecules, 12, 94 (1979). 7. J. Preston, Armide Fiers. In Kirk-thmer Encyclopedi of hemicl Technology, 3rd ed., John Wiley & Sons, ew York, 1978, vol I. K. Spiliopoulos nd J. A. Mikroynnidis, Mcromolecules, 31, 1236 (1998). 9. M. R. Bellomo, G. D. Psqule, A. L. Rose, A. Pollicino, nd G. Sircus, Polymer, 37, 2877 (1996). 10. S.. sio nd Y.. hng, Eur. Polym. J., 40, 1749 (2004). 11. X. G. Jin nd L. heng, J. Polym. Sci., Prt A: Polym. hem., 37, 1565 (1999). 12. X. L. Zhu nd X. G. Jin, J. Polym. Sci., Prt A: Polym. hem., 42, 2026 (2004) Liu, P. T. Liu, J. Y. Wng,. R. Wu, P. Wng, nd X. G. Jin, hem. J. hin. Univ., 26, 558 (2005). 14. L. Z. hen nd X. G. Jin, Polym. J., 31, 560 (1999). 15. P. J. Flory, Proc. R. Soc. London, 73, 234 (1956). 16. A. M. Donld nd A.. Windle, Liquid rystlline Polymers,. R. luser, Ed., mridge University Press, mridge, Englnd, P. J. Flory, Advnces in Polymer Science, Liquid rystl Polymers I; Springer-Verlg, Berlin, B. Tmmi nd. Yegneh, Eur. Polym. J., 38, 933 (2002). 19. G. S. Liou nd S.. sio, J. Polym. Sci., Prt A: Polym. hem., 41, 94 (2003). 20. T.. Su, S.. sio, nd G. S. Liou, J. Polym. Sci., Prt A: Polym. hem., 43, 2085 (2005). 21. D. J. Liw, F.. hng, M. Leung, M. Y. hou, nd K. Muellen, Mcromolecules, 38, 4024 (2005). 22. Y.. Lee nd I. J. hung, Polym. Bull., 28, 441 (1992). Polym. J., Vol. 38, o. 5,

TEMPLATE SYNTHESIS OF Cu AND Cu-Sn NANOPARTICLES USING CARBON FOAM AS A SUPPORT. Ivania MARKOVA-DENEVA, Tihomir PETROV, Ivan DENEV

TEMPLATE SYNTHESIS OF Cu AND Cu-Sn NANOPARTICLES USING CARBON FOAM AS A SUPPORT Ivni MARKOVA-DENEVA, Tihomir PETROV, Ivn DENEV University of Chemicl Technology nd Metllurgy, 8, Kl. Ohridski lvd., Sofi,