Preparation and characterization of some physical properties of new copolymers containing azo linked

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1 Intrnational Journal of Scintific & Enginring Rsarch Volum 4, Issu 2, Fbruary Prparation and charactrization of som physical proprtis of nw copolymrs containing azo linkd Zainab A. Jabarah AL Mousway Abstract - A fiv nw typs of PVA copolymrs containing azo groups wr synthsizd using Cold Warm strfacation of PVA with 4,4-Azo dibnzoic acid, which was synthsizd by air oxidation of P-nitro bnzoic acid. Th structurs of th synthsizd compounds wr idntifid by FT- IR spctroscopy. Copolymrization of PVA with 4,4-Azo dibnzoicacid was targt to obtain nw polymric matrials with original physical and chmical proprtis adaptabl to spcific uss. Swlling, crosslinking and mchanical tsting studis will b conductd simultanously. Th azo polymrs having high molcular wight rang abov 72,000 g mol 1 wr solubl in most of th polar solvnts lik N,N-dimthyl formaldyhd, dimthylsulfoxid, and dichloromthan but thy wr all insolubl in xyln. Th swlling bhavior of ths hydrogls was rlatd to th dgr of cross linking. DSC analysis showd good thrmals by th rang C for fiv copolymrs. Indx Trms - Estrfaction, polyvinyl alcohol 72000, 4,4-Azo dibnzoic acid, crosslinking, swlling bhavior,dsc, and tnsil. 1 INTRODUCTION Polyvinyl alcohol (oftn abbrviatd as PVOH) is a watrsolubl synthtic matrial usd as an mulsifir and adhsiv, PVA can b modifid by raction of pndant OH groups with various ragnts to form nw polymrs with novl surfactant proprtis (Grg, t al.2010). Linar PVA is synthsizd from vinyl actat and availabl with various molcular wights (Martins, t al, 2000). PVA hav high hydrophilicity, good film-forming proprtis and outstanding physical and chmical stability, (PVA) is an xcllnt mmbran matrial for prparation of hydrophilic ultra filtration (UF) and nano filtration mmbrans (yang, t,al. 2008). Th tissu-lik high watr contnt and lastic proprtis mak hydro gls advantagous for many biological applications, including contact lnss, controlld rlas matrics, and bio adhsivs ( Pppas, t al, 1987 & Muhbach, 1997). Chmical modification is a powrful tool for obtaining polymrs with nw proprtis and thrfor for incrasing th scop of thir applications (zhang, t al, 2005). Azo compounds hav a grat biological activity as wll as industrial importanc bcaus of thir mutagnic and carcinognic ffcts (Patai, 1975). Thy ar capabl of oxidizing many compounds baring th functional groups R- N=N-R' (Azo-dys), in which R and R' can b ithr aryl or alkyl groups. Ths compounds ar widly usd and discardd in workr collctions. Additionally, azo-dys can caus biological altration (Houk, & Chung, 1992). Author works in Division of basic scinc, Agricultur collg, Baghdad univrsity. zainab2004a@yahoo.com Th purpos of this study was to prpar hydrogls mmbran from (PVA) With 4,4-azodibnzoic acid. Th physical proprtis of prpard polymrs was studid. 2 Matrial Instrumntal and Mthods: Poly (vinyl alcohol) with a molcular wight of g/mol (Fluka), and wr usd without purification. P-nitro bnzoic acid and othr solvnts. Infrard spctra of th azo compounds and its copolymr wr rcordd on (shimadzu, FTIR.8400s) in th rang ( ) cm -1 using KBr pllts. Molar conductanc of th copolymr was dtrmind in thanol (10-3 ) at room tmpratur using (Philips PW-Digital Conduct mtr). 2.1 Synthsis of PVA- 4,4-azodibnzoic acid copolymrs: 2.1.1Synthsis of 4,4-azodibnzoic acid: Synthsis of 4,4-azodibnzoic acid was obtaind by condnsation of P-Nitro bnzoic acid with itslf undr air oxidation, (Khalil, at l., 2007). As shown in schm (1) synthsis of copolymrs: (10 gm, mmol) of PVA was addd In 250 ml of 2-nkd round bottom flask containing magntic bar and dissolv with 100ml of distill watr fittd with thrmomtr. th mixtur was stirrd, hatd at 50 C till a clar solution was obtaind, fw drops (2-3 drops) of Conc. H 2 SO 4 was addd and th raction mixtur was stirrd for 2hr., cool with ic watr bath to 10 C for 30 min, thn (2.16 gm, 0.008mmol) of 4,4-azodibnzoic acid was addd and anothr (2-3 drops) of Conc. H 2 SO 4 was addd. Th raction mixtur was hatd for anothr 2 hours at C, Until light orang color of azo polymr was obtaind. Thn pourd on a glass mould and lft to dry slowly at room tmpratur in a dark plac for 2 days. Th drid sampl was thn washd with distilld watr to rmov th un ractd PVA matrials and r-drid again in an ovn at 30ºC for 2 hours and stord in a dry and dark glass box. Th xprimnt was rpatd with 20%, 30%, 40% and 50%.of PVA and 4,4-azodibnzoic acid compound, as shown in tabl (1), schm (1). TABLE 1

2 Intrnational Journal of Scintific & Enginring Rsarch Volum 4, Issu 2, Fbruary Th prcntag of polyvinyl alcohol racts with 4, 4- Azodibnzoic aci Sampl No. PEG SCHEME 1 4,4-Azodibnzoic acid color I 10% 2.16 Light orang II 20% 4.32 Light 0rang III 30% 6.48 orang IV 40% 8.64 Rddish orang V 50% Rddish orang Synthsis Of Copolymrs (Azo poly vinyl alcohol) Thrmal bhaviors of th modifid PEG-AZO and its modifid compounds with diffrnt prcntag wr studid using diffrntial scanning calorimtr (DSC- 60 Shimadzu) to idntify whthr th modification lads to produc cross linkd or/and graftd structurs. Each 10 mg sampl was wighd into an aluminum crimpd pan which gav an air tight sal and th rfrnc was mpty pan. Th instrumnt was calibratd using indium of known mlting point and hat of fusion, and th scanning rat of 10 ºC /min. 2.4 Solubility: 0.2 gm (M1) of ach compound undr invstigation was dissolvd in diffrnt solvnts (s Tabl 2) at 25ºC with continuous shaking for 12 hours and lft to stand ovrnight. Th solution was thn filtratd through pr wighd filtr papr No.41, and thn th filtr papr was r-wighd aftr a complt drying. Th diffrnc in wight givs th mass of th dissolvd sampl (M2). Th prcntag of solubility (S %) can b calculat from th following rlation (Finch, 1973) : S % = M2 / M1 x (1) 2.5 Copolymr Swlling: O 2 N Air NaOH C 6 H 12 O 6 COOH Swlling of copolymr was carrid out in watr at 25 C using film sampls with an avrag mass in th rang of gm. Th sampl mass to watr volum ratio was Th sampls wr rmovd from watr at th prdtrmind tim intrvals, wipd gntly with filtr papr and wighd using an analytical balanc. Th sampl mass chang rsulting from th watr uptak xprssd in prcnt was calculatd according to th formula: m = (m t m 0 ) / m 0 * 100 (2) HOOC N=N COOH Whr m 0 and m t ar th masss of dry and wt sampls, rspctivly. (Katazyna, t al., & Jatuphorn, t al., 2007). 4,4- Azo dibnzoic acid ( I) -(-CH2-CH2-) n OH - (2n-1) H 2 O (-CH 2 -CH 2 -O-) m C=O -(-CH 2 -CH 2 -)- n OH H 2 SO 4 N=N CO 3 Rsult and discuss : Th structur of th polymr was confirmd by spctral analysis (FT-IR) which show a strtching absorption of OH at ( cm -1 ), (C=O) =1730cm-1, azo group (N=N) = 1590cm -1,and C-O-C singl of stric group at 1095cm-1. Th polymr Azo - PVA is composd of pndant azobnzn groups through str linkags. Diffrntial scanning calorimtry (DSC) was usd to study th thrmal proprtis and kintic paramtrs involvd in th cross linking procsss, w find that th azo poly vinyl alcohol is good thrmal proprtis spcially whn mixd th 50% of PVA with 50% of 4,4- azo dibnzoic acid by rang ( C) and th rsult for all copolymrs obtaind in tabl (2). fig.(1). Azo Poly vinylalcohol (II) 2.3 DSC Analysis:

3 Intrnational Journal of Scintific & Enginring Rsarch Volum 4, Issu 2, Fbruary Fig. (1): DSC Curvs of Azopolymrs (I), (II), (III), (IV) and (V) of 10 C / min. Th xprimnts of swlling wr carrid out at room tmpratur (25 C). Th sampls wr wighd at diffrnt tim intrvals until th hydratd wight was constant. Absorbncy was calculatd as grams of watr pr gram of dry polymr. In th scond procdur a polymr sampl that had bn wighd accuratly was immrsd in distilld watr at room tmpratur and lft until quilibrium was attaind tabl(2), fig (2). All copolymrs obtaind in th study swlld in distilld watr. Th amount of absorbd watr was dpndnt on th matrial composition. Th most hydrophobic polymrs basd on poly vinyl alcohol and azo dibnzoic acid absorbd ( % ).Th sam incras of th PVA hydro gls obtaind by frzing-thawing procsss at 20 C/20 C has bn vidncd by othr rsarchrs, corrsponding to th rlativ swlling dcras ( Pat,achial, 2009). Fig. 2. Swlling bhaviors as a function of tim for copolymrs (I), (II), (III), (IV), and (V) in 25 C.

4 Intrnational Journal of Scintific & Enginring Rsarch Volum 4, Issu 2, Fbruary polymrs was studid by diffrntial scanning calorimtry (DSC) xprimnts, Th polymrs showd initial crosslinking tmpratur in th rang of C. ACKNOELEGMENT Th authors' wish to thanks Prof. Dr. Zakaria H. Aioub and Prof. Dr. Jawad K. Al-Khafaji, in Chmistry Dpartmnt, Collg of Education Ibn-Al-Haithm, Univrsity of Baghdad, for thir suprvision and hlp thm. Th synthsizd AZO-PVA drivativs wr solubl in organic solvnts such as DMF, DMSO, but thy wr all wk solubl in THF and pyridin and insolubl in thanol...tc, tabl (3). Whil th modifid PVA as diffrnt prcntag wr obsrvd lowr solubility than th pur PVA at th sam conditions and that could b copolymr lads to dcras th numbr of intr molculs hydrogn bonds of th copolymrs. Tnsil strngth is important for a matrial that is going to b strtchd or undr tnsion, thrfor, fibr hav nd good tnsil strngth to improv th tnsil of a polymr sampl. W tak th sampl which is strtchd by a machin such as an in stron, thn using Zwigl machin and continu to incras th amount of forc, on th sampl until it braks. Th strss ndd to brak th sampl rprsnts th tnsil strngth of th matrial. Sinc tnsil strss is th forc placd on th sampl dividd by th cross-sctional ara of th sampl, tnsil strss and tnsil strngth as wll as both masurd I unit of for dividd by units of ara and it is usually N/m 2 (Jang, 1994). Th rinforcing ordr can b writtn as follows :- Azo polyvinylalcohol (V) > Azo polyvinylalcohol (IV) > Azo polyvinylalcohol (III) >Azo polyvinylalcohol (II) >Azo polyvinylalcohol (I). S tabl (2). TABLE 2 Som proprtis of azo poly vinyl alcohol. Sampl Tnsil strngth DSC Swlling No. MPa dgr % I II III VI V CONCLUISION PVA polymr was modifid via strfaction of som OH groups with 4,4- di Azo Bnzoic Acid group, to obtain half strs with carboxylic acid groups, physical propartis of PVA-Azo copolymr mmbran was studid and. Watr absorption was dtrmind gravimtrically as a function of tim at room tmpratur. Th thrmal bhavior of th TABLE 3

5 Intrnational Journal of Scintific & Enginring Rsarch Volum 4, Issu 2, Fbruary Solubility of copolymrs in diffrnt solvnts at 25 C. Samp l No. DMSO DMF DMAC pyridin TH F xyln hxanol Chloroform Acton Tolun bnzn I S S S W W N.S N.S N.S N.S N.S N.S II S S S W W N.S N.S N.S N.S N.S N.S III S S S W W N.S N.S N.S N.S N.S N.S IV w w w W W N.S N.S N.S N.S N.S N.S V w w w W W N.S N.S N.S N.S N.S N.S -V.S= vry strong whn th prcntag rachd >80%, S= strong whn rachd 70%, W= slightly solubl wak whn rachd 50% and N.S = not solubl whn lss than 50%. REFERNCES [1] Chung, K.,Cmiglia, C.;Mutagnticity of azo dys: structur-activity raction rsarch,(1992)vol, 277, no. 3. Pp [2] Finch, C.; (1973). Poly (vinyl alcohol): proprtis and applications, Wily, Nw York. [3] Grg S., Bn M., (2010). Analysis of Modifid Polyvinyl Alcohol by GPC Viscomtry using th Agilnt 390-MDS Multi Dtctor Suit. Agilnt Tchnologis, Inc.UK,p.1-2. [4] Houk, v.,(1992). Th gntoxicity of industrial wasts and fflunts: a rviw, Mutation rsarch, vol. 277, no. 2, pp [5] Jatuphorn, W.; Naruman, S.; (2007). "Modification of polyvinyl alcohol for us as an lctrolyt mmbran in dirct mthanol ful cll, MSc. Thsis, King Mongkuts Univrsity of tchnology Thorburi, Bangkok. Pp [6] Jang, B.Z., (1994). Advancd Polymr composits Principls and Application ASTM. Intrnational Matrials Park. [7] Katarzyna, G.; Sylwstr, G.; (2002). In vitro dgradation of novl mdical biodgradabl aliphatic polyurthans' basd on E-Caprolacton and plutonic, with various hydrophlicitis, polymr dgradation ad stability 75, [8] Khalil, F.; Mohsn, H.; (2007). Nw aromatic polyamid with azo and phosphin oxid groups in th main chain, Turk.J. Chm. 31, [9] Muhlbach A, Mullr B, Pharisa C, Hofmann M, Sifrling B, Gurry D. (1997). Journal of Polymr Scinc A: Polymr Chmistry;35: [10] Martns, K.S. Ansth, (2000). Charactrization of hydrogls formd from acrylat modifid poly(vinyl alcohol) macromrs. Polymr 41, [11] Pat achia1,s. Flora1,C. Chr. Fridrich2, Y. Thomann2.(2009): Tailoring of poly(vinyl alcohol) cryogls proprtis by salts addition. xprss Polymr Lttrs Vol.3, No.5, [12] Patai, S.,(1975). Th chmistry of hydrazo, azo and azoxy groups. Part I, Wily, Nw York. [13] pppas, NA., ditr (1987): Hydrogls in mdicin and pharmacy. Proprtis and applications, vol III. Bocaraton: CRC Prss. [14] Ying Sh., Yulian P., (2008). UF mmbran of PVA modifid with TDI. Dsalination 221, [15] Zhang Jing, Tu Wiping and Xia Z., (2005).Rsarch progrss in polyvinyl alcohol modification, China Synth. Fibr Ind., 28 (1),57 60.