Polymer Chemistry Accepted Manuscript

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1 Polymer Chemistry Aepted Mnusript This is n Aepted Mnusript, whih hs een through the Royl Soiety of Chemistry peer review proess nd hs een epted for pulition. Aepted Mnusripts re pulished online shortly fter eptne, efore tehnil editing, formtting nd proof reding. Using this free servie, uthors n mke their results ville to the ommunity, in itle form, efore we pulish the edited rtile. We will reple this Aepted Mnusript with the edited nd formtted Advne Artile s soon s it is ville. You n find more informtion out Aepted Mnusripts in the Informtion for Authors. Plese note tht tehnil editing my introdue minor hnges to the text nd/or grphis, whih my lter ontent. The journl s stndrd Terms & Conditions nd the Ethil guidelines still pply. In no event shll the Royl Soiety of Chemistry e held responsile for ny errors or omissions in this Aepted Mnusript or ny onsequenes rising from the use of ny informtion it ontins.

2 Pge 1 of 5 RSCPulishing Cite this: DOI: /x0xx00000x Reeived 00th Jnury 2012, Aepted 00th Jnury 2012 DOI: /x0xx00000x L-ltide polymeriztion hs een studied y One NMR Tue Experiment. Trditionl 1 NMR, providing struture, onversion nd numer verge molr mss ( ) hs een omined with Diffusion Ordered Spetrosopy (DOSY), yielding mss verged molr mss ( ). Thus, omplete kineti experiment ould e performed without smpling, in one NMR tue. Diffusion Ordered Spetrosopy (DOSY) hs een elorted ove fifty yers go nd tody every NMR spetrophotometer hs pility to ondut DOSY experiments. DOSY gives the dependene of the intensity of the pek sried to the given nulei on its diffusion oeffiient (D) nd mgneti field grdient. 1 The physil priniple of DOSY hs een explined lerly in literture nd vrious spets of experimentl set-up hve een disussed. 2-4 An exhustive review of originl ppers devoted to the method nd its pplitions in vrious res of orgni hemistry, inluding polymer hemistry, hs lso een pulished. 5 In polymer hemistry DOSY hs mostly een used in determintion of. This method hs lso een pplied in our present work on L-ltide polymeriztion, to omplement our kineti work. The detiled desription of the theoretil ses of the method, eventully relted to the Stokes-Einstein reltion-ship (1) of the size of moleules nd their diffusion oeffiients hs een given in severl ppers. 6-9 TkB D= 6πηR Where T is the solute temperture, k B is the Boltzmnn onstnt, η is visosity of the medium, nd R is hydrodynmi rdius of the studied moleule. On the sis of the men field theory molr mss M is relted to R nd leds to the dependene of M on D ording to the simple eqution (2), resemling the Mrk-ouwink-Skurd eqution. 10 (2) R = KM ν K is proportionlity onstnt nd ν is sling exponent. L-Ltide Polymeriztion Studied y 1 NMR with Diffusion Ordered Spetrosopy (DOSY). One NMR Tue Experiment Providing: Conversion, Polymer Struture, nd. P. Lewinski, S. Sosnowski, * S. Kzmierski nd S. Penzek * (1) Finlly, the reltion etween M nd diffusion oeffiient hs reltively simple form (3). D= K ' M ν (3) The K nd ν oeffiients hve een determined for few polymer-solvent systems. 7,11-13 Reently Grus et l. in pper entitled Applition of 1 DOSY for File Mesurement of Polymer Moleulr Weights pplied DOSY for the first time in studies of ontrolled polymeriztion of styrene nd of 1,5-ylootdiene (ROMP). 13 The onversion nd mss verge molr mss ( ) dt hve een determined in the Grus pper y smpling the retion mixture. We deided to follow the Grus pproh nd study the L-ltide (LA) polymeriztion in this wy, lthough in ple of smpling the retion mixture we performed polymeriztion in seled NMR tue, quiring ll the informtion on-line without tking smples. This ws possile euse the rte of the studied proess is suffiiently slow t the mesurement temperture, ssuring tht neither the mesurements nor the polymeriztion were distured. This work is divided into three prts. In the first one the dependene of diffusion oeffiient on for poly(l-ltide) (PLA) is given. In the seond this dependene is verified in kineti experiment with smpling the polymeriztion mixture. The third is devoted to the tul One NMR Tue Kineti Experiment. All experimentl detils, nlytil proedures, results of hrteriztion of the synthesized smples re desried in the Eletroni Supplementry Informtion (ESI). Five smples of PLA were prepred (polymeriztion with Sn(2- ethylhexnote) 2 (Sn(Ot) 2 )/enzyl lohol (BzO) tlyti system) nd preipitted from the polymeriztion solution. were mesured y SEC nd D using DOSY. In ddition, numer verge molr msses were determined y 1 NMR nd SEC nd ompred with lulted from the onditions of polymeriztion. The tulted (Tle 1) dt were used to determine the nlytil dependene of D on (Figure 1). Then the reltive differene (lled error ) etween determined y SEC nd lulted from D, using the estlished nlytil dependene is given in the lst olumn of Tle 1. Aepted Mnusript This journl is The Royl Soiety of Chemistry 2012 J. Nme., 2012, 00, 1-3 1

3 Pge 2 of 5 Tle 1 Chrteristis of PLA smples As seen from the dt olleted in Tle 1, the determined y SEC with MALLS detetor nd from integrtions of signls in the 1 NMR spetr re onsistent with the theoretil ones, sed on the rtio x[LA] 0 /[BzO] 0. Differenes noted for the lulted nd mesured smllest msses ould e sried to the frtiontion-removl of the lower mss moleules during preipittion of the rude smples. Low dispersities (Ð) (rnging from 3 to 9), indite ontrolled ehviour of the pplied polymeriztion proess. The DOSY spetr for PLA solutions were quired ording to the protool used y Grus et l. (detils given in ESI). 13 A novel ITAMeD lgorithm nd the Mtl sript provided reently y Urńzyk et l. hve een used for extrtion of D vlues from ttenution dey urves. 6 Compring with other methods, ITAMeD does not require ny ssumptions on omposition of the nlysed smple. The NMR signl dey urves nd otined diffusion oeffiient distriutions re presented in the ESI. The numeril vlues of D nd re given in Tle 1. log(d) id (th) D = (±0.03) (±0.006) PLA enzene ltide log( ) r 2 = Fig. 1 Weight-verged moleulr mss ( ) vs. diffusion oeffiient (D) log-log plot for PLA in enzene-d6. In Figure 1 the dependene of the diffusion oeffiients on the orresponding mss verge molr msses is given. A stright line fits the experimentl dt with orreltion oeffiient r 2 = nd psses losely to points otined for enzene nd LA. The proportionlity onstnt K is equl to (±0.03) nd vlue of the sling exponent ν = 0.598(±0.006). The vlue of the sling exponent indites tht enzene is good solvent for PLA, s it ws estlished erlier on the sis of visosity mesurements. 14 The D vlues extrted from DOSY spetr using the T1/T2 TopSpin module yield nerly identil result s the ITAMeD method: K = (±0.03) nd ν = 0.597(±0.006) (f. Figure S5 in ESI). The vlues, lulted from nlytil reltionship (f. Figure 1), were then ompred with determined y SEC. The highest notied differene ws equl to 6.3 %. Even though the estlished dependene is vlid only for the polymer onentrtion of 0.5 g l -1, fter determining orretion ftors it hs een suessfully pplied in studies of polymeriztion kinetis with hnging onentrtion of the formed polymer. Polymer onentrtion s hnges my lso influene the diffusion oeffiient y ggregtion phenomen or simply y inresing solution visosity. In order to orretly nlyse the experimentl dt the dependene of D on polymer onentrtion (from 0.5 to 30 g l -1 ) hs een determined nd plotted s in Figure x D, m 2 s Đ D orr D d (m 2 s -1 ) D exp onentrtion, gl -1 Fig. 2 Dependene of the D on nd onentrtion of polymer. Open mrks: dt used for determining of plot slopes. Crosses: dt used for onfirmtion of linerity of the onentrtion dependene. Strs illustrte orretion introdued y eqution 4. Numers indite of smples. d error e (%) A B C D E Bsed on stoihiometry nd onversion. Integrtion of 1 NMR spetr. SEC with MALLS detetion. d DOSY NMR in C 6 D 6. e ( (SEC)- (DOSY))*100/ (SEC). The dependenies re liner nd slopes do not depend on molr msses. It follows tht the men vlue of the slope (S) is equl to (1.3±0.2) m 2 l g -1 s -1 nd it is ommon for ll molr msses within the studied rnge. Thus, the orreted vlue of the diffusion oeffiient n e lulted from eqution (4): D orr = D exp S( exp - orr ) (4) Where: is onentrtion; indies exp nd orr men experimentl nd orreted vlue, respetively. Finlly the vlues were lulted from the D orr using eqution given in Fig. 1. After hving estlished the dependene of D on nd polymer onentrtion, it hd een neessry to verify the orretness of this reltionship efore performing the One NMR Aepted Mnusript 2 J. Nme., 2012, 00, 1-3 This journl is The Royl Soiety of Chemistry 2012

4 Pge 3 of 5 Tue Experiment. Therefore kineti experiment on L-ltide polymeriztion ws first performed with smpling of the polymeriztion mixture (protool nd onditions of experiments re given in ESI). The determined molr msses re given in Tle 2. Tle 2,, Ð nd D s determined y SEC, 1 NMR nd DOSY mesurements in the kineti experiment with smpling id Dt olleted in Tle 2 (s well s Figure S8 in ESI) show, tht for the ded mromoleules oth the DOSY nd SEC methods give lmost identil nd. This dditionlly indite tht the reltionship etween nd D hs een orretly determined. Moreover, Ð of polymer smples rnge from 0 to 7, s expeted for hins formed in the ontrolled-living polymeriztion. 7.5 C 6 D 6, 7.0 d,d' 2 C O d x f O C 3 O C O e d' 5.5 Đ e 5.0 C 3 C OSnO e' d,d' f' x δ / ppm Fig. 3 1 NMR 500 Mz spetrum of the living PLA in C 6 D 6 initited y Sn(Ot) 2 /BzO system. Temperture 353 K, retion time 12 h, [LA] 0 = mol l -1, [BzO] 0 = mol l -1, [Sn(Ot) 2 ] 0 /[BzO] 0. Integrtions (proton numer): d =, e = 134.0, monomer = e' Applition of DOSY for studies of the polymeriztion kinetis of L-Ltide using the One NMR Tue Experiment pproh is illustrted y polymeriztion onduted in seled NMR tues (experimentl detils re given in ESI). Polymeriztion mixture, ontining C 6 D 6, LA, nd inititing-tlyti system Sn(Ot) 2 / BzO, ws prepred nd trnsferred into NMR tue under vuum. The tue ws then seled-off nd kept in thermostt t 353 K. At predetermined time intervls the tue ws ooled nd 1 NMR s well s DOSY spetr of the polymerizing mixture were quired t 298 K. At this temperture, during the time of mesurements (20 min), polymeriztion prtilly does not tke ple. e' 4.0 O monomer 3.5 g C h' 2 C j 2 C h C x g g Đ d i C h,h' f, f' D (m 2 s -1 ) SEC with MALLS detetion. Integrtion of 1 NMR spetr. From DOSY. d ( 1 NMR)/ (DOSY) monomer j i 0.5 Tle 3 Conversion, P n,, D, nd Ð determined from 1 NMR nd DOSY mesurements for the One NMR Tue Experiment time s The monomer onversion nd degree of polymeriztion P n hve een determined from integrtions of the stndrd 1 NMR spetrum (Figure 3). The spetrum shows the struture of tive mromoleules eing in equilirium with the temporrily intive hins with O end groups, in greement with ref. 15. The monomer onversion ws lulted from the rtio of integrtion of the methine protons of the ltoyl units e signl (overlpped qurtets t δ = ppm) to integrtion of the monomer signl (qurtet entred t δ = 3.75 ppm). Signls e nd g re rodened due to equilirium etween tive nd intive hins nd therefore nnot e used for lultions of P n of living mromoleules. P n nd were lulted from the rtio of integrtions of signls e nd d (the ltter t δ = 4.89 ppm). -ln{1-p n [I] o /([M] o -[M] e )} onv. P n time / s D Đ m 2 s d numer of LA units. BzO nd SnOt end grups. / d quenhed Fig. 4 Kineti plot of the polymeriztion of LA in C 6 D 6 initited y Sn(Ot) 2 /BzO system. Temperture 353 K, [LA] 0 = mol l -1, [BzO] 0 = mol l -1, [Sn(Ot) 2 ] 0 /[BzO] 0. Figure 4 presents the experimentl plot of the left hnd side of eqution 5 s funtion of time. [ I] P 0 n ln 1 = k [ I] t p 0 (5) [ M] [ M] 0 e The orresponding eqution hs een derived for living irreversile polymeriztion in one of our previous works y omining ln([m] 0 /[M] t ) = -k p [I] 0 t nd P n = ([M] 0 -[M] t )/[I] Eqution 5, fter introdution of [M] e, is vlid for the reversile Aepted Mnusript This journl is The Royl Soiety of Chemistry 2012 J. Nme., 2012, 00, 1-3 3

5 Pge 4 of 5 polymeriztion nd n e used for determintion of the propgtion rte onstnt. The linerity of the plot (s in Figure 4) mens tht termintion nd irreversile trnsfer re simultneously sent. [I] 0 in Eqution 5 is equl to the invrint onentrtion of the living growing hins. owever, in the system studied in this work, the onentrtion of the growing hins, eing invrint, is neither equl to [Sn(Ot) 2 ] 0 nor to [BzO] 0. As the mjor im of this work is demonstrtion of the One NMR Tue Experiment, it suffies to estimte the [I] 0 vlue using n pproh presented in the work from our lortory s well s the kineti studies y Moridelli. 17,18 It hs een determined in our work, tht the instntneous onentrtion of the tive entres is funtion of [RO] for n invrint [Sn(Ot) 2 ] For the onditions used in the present work [P*] [RO]/3 (where [P*] is the onentrtion of the momentrily tive speies. This results from formtion of tive speies in the reversile retion of Sn(Ot) 2 nd BzO, followed y the propgtion step with reversile inter-onversion of tive hins into the temporrily intive ones. The slope in Figure 4 (k p [I] 0 ) is equl to s -1 nd it follows tht k p ~ l mol -1 s -1 ([I] 0 = mol l -1 ) whih is lose to l mol -1 s -1, lulted tking into ount the temperture oeffiient for k p s determined y Moridelli in ulk for the temperture rnge from 403 to 483 K. 18 The vlues of diffusion oeffiients for the instntneous polymer onentrtions were extrted from the on-line quired DOSY spetr nd orreted to the proper onentrtion (eq. (4)). vlues were otined from eqution given in Figure 1. - D 10 3, quenhed onversion Fig. 5 Dependene of, nd Ð on onversion in living polymeriztion of LA in C 6 D 6 t 353 K, initited y Sn(Ot) 2 /BzO. [LA] 0 = mol l -1, [BzO] 0 = mol l -1, [Sn(Ot) 2 ] 0 / [BzO] 0. Solid line is the lest squre fit to the dt. Numeril dt in Tle 3. In Figure 5 the dependenes of nd on onversion re given. Ð vlues shown in the figure were lulted s equl to the rtio /. The determined vlues of (nd therefore lso Ð) re higher thn expeted for ontrolled-living polymeriztion. There re severl possile resons: ggregtion of the living hins, reversiility of propgtion, prtiulrly importnt t higher onversion, nd interonversion of the tive nd temporrily intive hins. All these phenomen vnish for quenhed smples. Indeed, (nd therefore lso Ð) drop to the level hrteristi for mromoleules formed in the ontrolled living onditions. Corresponding results otined from 1 NMR/DOSY nd SEC nlyses of the killed polymers re shown in Tle 2. A derese of nd Ð ws notied lso fter quenhing the polymeriztion in the One NMR Tue Experiment (f. Tle 3 nd Figure 5). ene, the desried metodology gives lso n insight into the sutle phenomen in the polymerizing systems. Conlusions It hs een shown, in the ontrolled polymeriztion of L-ltide, tht omintion of different NMR tehniques (stndrd nd DOSY) llows studying on-line the kinetis of polymeriztion together with determintion of, nd Ð. Moreover, in the sme experiment rried out in single NMR tue, the poly(l-ltide) struture nlysis hs een possile. Aknowledgements We thnk MS Mteusz Urńzyk nd Prof. Krzysztof Kzimierzuk, University of Wrsw, Polnd, for kindly dvies on the pplition of the ITAMeD lgorithm. This work ws supported y Lmn projet PBS2/A1/12/2013 nd Ntionl Siene Center, Polnd. Notes nd referenes Centre of Moleulr nd Mromoleulr Studies Polish Ademy of Sienes, Sienkiewiz 112, Lodz, Polnd. E-mil: spenzek@mm.lodz.pl, stsosno@mm.lodz.pl.. Address here. Address here. Footnotes should pper here. These might inlude omments relevnt to ut not entrl to the mtter under disussion, limited experimentl nd spetrl dt, nd rystllogrphi dt. Eletroni Supplementry Informtion (ESI) ville: experimentl proedures, NMR nd SEC dt. See DOI: /000000x/ 1 E. O. Stejskl, J.E. Tnner, J. Chem. Phys., 1965, 42, J. N. Mki, N. M. Loening In Modern NMR Spetrosopy in Edution, Eds.: D. Rovnyk, R. Stoklnd, Amerin Chemil Soiety, 2007, h W. S. Prie, Conepts Mgneti Res., 1997, 9, W. S Prie, Conepts Mgneti Res., 1998, 10, C. S. Johnson Jr., Prog. NMR Spetros., 1999, 34, M. Urńzyk, D. Bernin, W. Koźmiński, K. Kzimierzuk, Anl. Chem., 2013, 85, A. Chen, D. Wu, C. S. Johnson Jr., J. Am. Chem. So., 1995, 117, A. Jershow, N. Müller, Mromoleules, 1998, 31, K. F. Morris, C. S. Johnson Jr., J. Am. Chem. So., 1993, 115, M. Doi, S. F. Edwrds, The Theory of Polymer Dynmis, Oxford University Press, 1994, h S. Augé, P.-O. Shmit, C. A. Cruthfield, M. T. Islm, D. J. rris, E. Durnd, M. Clemney, A.-A. Quoineud, J.-M. Lnelin, Y. Prigent, F. Tulelle, M.-A. Delsu, J. Phys. Chem. B, 2009, 113, R. Plummer, D. J. T. ill, A. K. Whittker, Mromoleules, 2006, 39, W. Li,. Chung, C. Deffler, J. A. Johnson, R.. Grus, Mromoleules, 2012, 45, Aepted Mnusript 4 J. Nme., 2012, 00, 1-3 This journl is The Royl Soiety of Chemistry 2012

6 Pge 5 of 5 14 A. Shindler, D. rper, J. Polym. Si.: Polym. Chem. Ed., 1979, 17, A. Kowlski, A. Dud, S. Penzek, Mromoleules, 2000, 33, S. Penzek, P. Kuis, R. Szymnski, Mromol. Chem. Rpid. Commun., 1991, 12, A. Kowlski, A. Dud, S. Penzek, Mromoleules, 2000, 33, Y. Yu, G. Storti, M. Moridelli, Ind. Eng. Chem. Res., 2011, 50, Aepted Mnusript This journl is The Royl Soiety of Chemistry 2012 J. Nme., 2012, 00, 1-3 5