AQUEOUS SEC-MALLS OF AMINE FUNCTIONAL POLYMERSDERIVED FROM N-ETHENYLFORMAMIDE

Dennis J. NagyAir Productsand Chemicals, Inc.

Allentown, PA 18195

Presented at the 1994 Intemational GPC Symposium,Orlando, Florida, June 1994

Introduction "

N-ethenylformamideis a new,water-solublemonomerused inthe polymerizationof aminefunctionalpolymerssuchas poly(ethenylformamide),or PEF, which is aprecursorfor poly(vinylamine). Poly(vinylamine)containspendant,primaryaminefunctionalityalongthe polymerbackboneand can existas the free amineor cationicsalt. This makesthe polymersuitablefor applicationssuchas waste-water treatment,paper coatings,personalcare products,textiles,and adhesives.N-ethenylformamideis very useful as the startingpointfor the synthesisofpoly(vinylamine)sincevinylaminesare not stableand do notpolymerize.

N-ethenylformamide(structureshownin Figure 1) is readilypolymerizedbyfreeradical initiatorsusingprecipitation,aqueoussolution,or inverseemulsionpolymerization. Dependingon the polymerizationprocessemployed,themolecularweightof the resultingPEF can range from lessthan 50,000 daltonsto greaterthanone milliondaltons. Aqueoussolutionor solventprecipitationpolymerizationis usuallyused to synthesizehomopolymersof PEF inthe 50,000to 500,000 molecularweight rangewith polydispersitiesof 2.0 to 3.5. Highmolecularweight homopolymersof PEF of one milliondaltonsor greater arepreparedby inverse emulsionpolymerization. N-ethenylformamidemonomercan also be copolymerizedwith a variety of unsaturatedmonomerssuch as vinylacetate, acrylamide,butylacrylate,and methylmethacrylate(1).

Water-solublehomopolymersof PEF may be hydrolyzedwith eitherstrong acidsor bases as shownin Figure2. Poly(vinylamine)inthe free base form may bepreparedby addingan equivalentamountof base for the desireddegree ofhydrolysis.Poly(vinylamine)hydrochloridesalt (PVam-HCI) may be prepared byaddingan equivalentdegree of acid for the desired degreeof hydrolysis,resultingin a cationicpolymer.

The physicalpropertiesand performanceof PEF, free basepoly(vinylamine)andcationicPVAm-HCIare stronglydependenton the molecularweightandmolecularweight distribution. For example,the relationshipof solutionviscosityand molecularweightof PEF is linear overa wide range(1). In applications

71

such as waste-water treatment, the efficiency of particulate flocculation isstrongly dependent on the molecular weight of PVAm-HCI. Thus, it is critical thssensitive and reliable methods such as aqueous size exclusion chromatography(SEC) be employed for molecular weight analysis. In addition to molecularweight, the determination of polymer size is an important physical propertymeasurement. For example, size determination is very useful for studying thediffusion of a polymer through a porous substrate, the effect on solution viscosit_or thickening, and the sensitiyity of an ionic polymer, such as PVAm-HCI, tovarious salt conditions. Light scattering, particularly the angular variation ofscattered light, is the principal means for characterizing polymer size in solution.The use of aqueous SEC coupled to multi-angle laser light scattering (MALLS)detection is a powerful tool for the measurement of absolute molecular weightand polymer size of amine functional polymers.

MALLS has added a new dimension in the characterization of PEF and cationicPVAm-HCI over other techniques such low-angle laser light scattering (LALLS)and differential viscometry. As will be desc,ribed, SEC-MALLS provides absolutemolecular weight, size, and conformational information. MALLS is a primarytechnique since it can determine molecular weight and size in solution,independent of elution volume and without the need for column calibration.MALLS measures the angular dependence of scattered light which directlyresults in the determination of polymer size. This unique capability distinguishesthe technique from a single, angular measurement such as LALLS whichprovides only molecular weight and no size or conformational information.

Polymer size is often referred to as the "radius of gyration." However, truepolymer size is more correctly defined as the so-called root mean square (RMS)radius, typically the z-average when a distribution of molecular sizes is present.Once molecular weight and RMS radius of a polymer are determined over adistribution, it then becomes possible to examine conformation or shape (2).

This paper describes the application of aqueous SEC-MALLS for characterizingmolecular weight, RMS radius, and conformation of PEF and homopolymers andcopolymers of cationic poly(vinylamine). SEC of free base poly(vinylamine) isnot presented and is reserved for future discussions.

MALLS Theory for Molecular Weight and Size

Forsolvatedmoleculesat low concentrations,the weight-averagemolecularweight (Mw) andthe z-average meansquare radiuscan be determinedfromtheexpandedformof the Rayleighequation"

K c / R(e) = (1 / Mw) [1+ (16=2/3Zo2) <rg2>sin2(ei2)] + 2A2 c [1]

?2

whereR(9) is the lightscatteredby the solutionat an angle 0 inexcess of thatscatteredby the pure solventdividedby the incidentlight intensity,c isthe

molecularconcentration,Zo is the.yacuumwavelengthof the incidentlight,<rg2>is the mean-squareradiusof gyration,and A2 is the secondvirial coefficient.The opticalconstant

K = 4 _2no2(dn/dc)2/ [Zo4 NA] [2]

where no isthe refractiveindexof the solvent,dn/dc is the specificrefractiveindexincrementof the polymerat the same wavelength of lightas the lightscatteringinstrument,and NA isAvogadro'snumber.

Molecularweightsare calculated acrossall incrementsof a chromatogramusingthe Debye plotof R(e) / K c versussin2(0/2). The y-interceptis the weight-averagemolecularweight,Mw, and the slope is the mean-squareradiusofgyration,<rg2>. Under conditionsnormallyused in SEC, the quantity2A2 c isusually<< 1 and can be ignored.

Experimental Procedures

Figure3 is a schematicof our instrumentsetupused for aqueousSEC-MALLSmeasurementsof PEF and PVAm-HCI. The MALLS photometerwas configuredinseriesbetweenthe SEC instrumentand a refractive index(RI) detector,usedformeasuringconcentration. For these studies,the SEC consistedof a Waters150C GPC interfacedto a Waters Model410 RI detector (Waters/MilliporeCorporation,Milford, MA) and a Wyatt TechnologyModel Dawn F MALLSphotometer(Wyatt TechnologyCorporation,Santa Barbara,CA). Our Dawn Futilizeda 10 milliwatt,488 nm argon-ionlaser with verticallypolarized lightandupto 15 fixed angles of detection(35.5° to 144.5°). A set of Toyo SodaTSK-PW columns (Toyo Soda Corporation)were used for the separationof PEF inthe SEC at 35° C with a flowrate of 1.0 ml/minand an aqueous mobilephaseof0.05 M sodiumnitrate in Milli-Qwater (MilliporeCorporation). A set ofSynChromCATSEC columnswere usedfor the separationof PVAm-HCIat aflowrate of 0.4 ml/minat 35° C. The mobilephase consistedof variousconcentrationsof sodiumnitratefrom0.005 to 0.30 M with 0.1% trifluoroaceticacid (TFA) at pH =2.5. Differentsalt concentrationswere used to examinetheeffecton polymerRMS radius.

Molecularweight,RMS radius,andmolecularweight distributionare calculatedusingASTRA-EASI softwarefrom WyattTechnology. Specificrefractiveindexincrement(dn/dc)valueswere measuredon a Wyatt TechnologyOptilab903Photometer. A dn/dc plotfor PEF is shownin Figure4 (dn/dc = 0.155 ml/gfromthe y-axis intercept) alongwith that for another nonionic,water-solublepolymer,poly(vinylalcohol) (PVA). PVA exhibitsa similarvalue of 0.150 ml/g.

73

PVAm-HCIwas also characterized usinga Wyatt Technology Mini-DawnMALLSphotometerunder the same conditionsdescribedabove. The Mini-Dawnutilizesthreeangles of detection(45°, 90°, and 135°) witha 690 nm,20 milliwattphotodiodelaser. Molecularweightand RMS radiuscalculationsare calculatedusingASTRETTE softwarefromWyatt Technology.

Boththe Dawn F and Mini-Dawn requireinstrumentcalibrationand normalizationof the photodiodedetectorswhichsurroundthe flowcell and monitorlightintensityat a givenangle. Instrumentcalibrationis requiredbecausenomeasureof the transmittedlaser lightintensitythroughthe sample is possibledue to the flow-cellconfiguration. Since the photodiodedetectorsexhibitdifferentgains,normalizationis necessary(3). Normalizationmustbe performedwith an isotropicscatterer, usuallya lowmolecularweightpolymer. In ourcase,a monodisperse,poly(saccharide)standard(a maltotriose)with a molecularweight of 23,700 daltonsand polydispersityof 1.07 is used (PolymerLaboratories,Amherst,MA).

Characterization of PEF using the Dawn-F

The use of an aqueous-basedmobilephasefor measuringlightscatteringcanprovequitechallengingsince water is a notoriousscattererof contaminantsanddust,especiallyat lowangles. Inthis regard, lightscatteringmeasurementsinorganicsolventssuch as tolueneor tetrahydrofuranare considerablyeasier touse. The use of an aqueous mobilephase requiresproperfilteringandpreparationin lightscatteringanalysessuch as MALLS. A convenientway toexaminethe lightscatteringresponsefrom each angle of detectionis shown inFigure 5 for PEF. The chromatogramsfrom all 15 anglesof detection(includingthe RI chromatogram)are overlaidas a functionof detectorangle. Detectornumber4 is 35.5°, the lowestaccessibleangleon the Dawn-F for the cellconfigurationused (K5 type). Detectornumber11 correspondsto 90° anddetector number18 is 144.5°. Notethe low degreeof baseline noise (lowamountof excessscattering) inthe chromatogramat 35.5°. This angle is themostsensitiveto excessscatter. For thiswork,ourmobilephase was filteredthrougha 0.22 micronmembraneandwas allowedto recyclethroughthe SECduringtimeswhen MALLS measurementswere notbeing made. This exampleillustratesthe importanceof usingclean, prefilteredsolventsfor performingMALLS measurementsunderaqueous conditions. With propercare andpatience, it is possible to obtainchromatographiclightscattering resultsas goodas thosefrom organic-basedSEC-MALLS.

It is also importantto note in Figure5 how the chromatogramsexhibit a gradualincrease in intensitywith decreasingdetectorangle (decreasing detectornumber). It isthisangularvariationwhich enablesdeterminationof the RMSradius.

74

Molecular weight distribution curvesfor three molecularweightgrades of PEFare shownin Figure6. The lowmolecularweight PEF exhibitsMw = 43,400 witha polydispersityof 2.0, the mediummolecularweightPEF exhibitsMw = 293,000witha polydispersityof 3.0, and the highmolecularweight PEF exhibits Mw =1,605,000 witha polydispersityof 2.5.

The data in Table 1 summarizeMw and RMS radiusvaluesfor eight differentmolecularweightsof PEF rangingfromapproximately40,000 daltonsto 700,000daltons. The data showthe expectedtrendin whichRMS radiusincreaseswithincreasingmolecularweight.

RMS radiusdata for low molecularweightpolymersare particularlychallengingbecausethey exhibit littleor no angularvariationin scattered light intensity. Thedata inTable 1 raisethe questionas to how lowan RMS radiuscan bemeasuredfor PEF. Fromourdata we havemeasureda value of 9.5 nmwhichcorrespondsto a weight-averagemolecularweightof 40,600 daltons. Theminimumradiusthat can be determinedby lightscatteringis (Z/20)/2, where _,=;Lo/no(4). Forourwork,no= 1.332 (the refractiveindexof the aqueousmobilephase) and Zo= 488 (the laserwavelength). Fromthis calculation, the lowestmeasuredvalue for the RMS radius is9 nm, in excellentagreementwith ourmeasuredvalue of 9.5 nm.

The measurementof molecularweightand RMS radiusprovidesthe meanstoexaminethe conformationalcharacteristicsof a polymerusingthe relationship:

RMS = k Mo_ [3] Jt

where c_isthe conformationalcoefficientandk is the proportionalityconstant. It !is known that o_= 1.0 for a rigidrods,0.5 for randomcoils ina theta solvent,and0.33 for a sphere. FIoryhas shownthat the value forc¢of a polymer ina goodsolventis 0.55 - 0.60 (5). The conformationalcoemcientis determinedfromtheslopeof a log-logplotof RMS radiusversusmolecularweight. Such a plotfor alow-mediumweightPEF is shown in Figure7. The slopecorrespondsto an o_value of 0.51 or that of a randomcoil in a theta solvent. This resultsuggeststhat the mobilephase solutionof 0.05 M sodiumnitrateis closerto that of atheta solventfor PEF than that of a thermodynamicallygoodsolvent.

A summaryof polymerconformationdata for PEF andseveralother common,water-solublepolymerswhich we have examinedby SEC-MALLSare shown inTable 2. Fully-hydrolyzedpoly(vinylalcohol), partially-hydrolyzedpoly(vinylalcohol),poly(ethyleneoxide),poly(saccharide),alongwith PEF exhibit valuestypicalfor randomcoil polymers. The o_value of 0.38 for the commercialdextranis consistentwith the fact that this materialis highlybranched. Similarvalueshavealso been reportedusingaqueousSEC-MALLS (6).

75

Table 1MALLS Data for PEF

Mw RMS Radius, nm

40,600 9.584,100 13.1

145 000 19.2195 000 23.2222 000 25.3276 000 27.8366 000 30.3700 000 48.3

Table 2ConformationalValues for PEF

and SelectedNonionicWater-Soluble Polymers

Polymer o_

PEF 0.51Fully-HydrolyzedPVA 0.50

Partially-HydrolyzedPVA 0.48Poly(ethyleneoxide) 0.49

Poly(saccharide) 0.56Dextran 0.38

Calculationof molecularweightusing SEC-MALLS does not require inputof anexact valuefor the mass of polymerinjected if the dn/dc value is known. Thisprocedureknownas the "drYdcMethod" in the ASTRA softwarecan provequiteusefulsince itcalculatesa theoreticalmass injected. Percent recoveryof thepolymerthroughthe SEC can then be determined. Figure8 exhibitsRI and 90°chromatogramsfor a PEF withthe limits(shownas verticalarrowsto the left anddght of the chromatograms)for the molecularweightcalculations. Over theselimits,a theoreticalmassinjectedwas calculatedas 0.57 mg usinga dn/dc=0.155. The actual calculatedmasswas 0.59 rag,determinedfromthe knownconcentrationof the PEF solutionand the injectedvolume of 0.200 ml. Thepercent recoverywas 103%. However, if thisPEF was initiallypresentas asolutioninwhichthe concentrationof PEF was notpreciselyknown(forexample,approximately20% weightsolids),we wouldstillbe able to calculate

76

molecularweightvalues using dn/dc = 0.155. This procedure can also proveveryusefulwhen measuringmolecularweight of PEF ina formulationinwhichthe exactconcentrationof the polymeris not known.

Characterization of Cationic Poly(vinylamine) using the Dawn-F

The acid-hydrolyzedproductfromPEF, PVAm-HCI, can be readilycharacterizedby aqueousSEC coupledwith MALLS detection. These type of cationicpolymerselutewithoutadsorptionusingSynChromCATSEC columnsandeluantsof varying ionicstrengths(7). CATSEC columnsemploya crosslinkedpoly(ethyleneimine)coatingon silica packingwhich impartsa cationicchargeon the surface.

Figure9 showsan overlayof the 90° and RI chromatogramsfor a PVAm-HCIhomopolymerwith Mw = 102,000 and an RMS radius= 24.3 nm. Thisseparationwas performedusinga mobilephase ionicstrengthof 0.05 M sodiumnitratewith 0.1% trifluoroaceticacid (pH = 2.5). The MALLS chromatogramofthe polymerexhibitsonlyminimalbaselinescatter (noise).

The ionicstrengthof the mobilephasewill directlyaffectthe elutionvolumeandthe RMS radiusvalue of PVAm-HCI. Figure 10 is a plotof molecularweight(calculateddirectlyusingASTRA) versuselutionvolumefor a PVAm-HCIhomopolymer(Mw = 95,000) for three ionicstrengthlevels in the mobilephase.These include0.008 M (TFA only, no sodiumnitrate),0.02 M sodiumnitratewith0.1% TFA, and0.20 M sodiumnitratewith 0.1% TFA. As the ionicstrengthof

the mobilephaseincreases_suppressionof electrostaticdouble layer effects Ibetweenthe packingand polymerresultsin an increase inelutionvolume,as !morepore volumein the SEC packing becomesaccessibleto the polymer. Atlowionicstrengths,the increased levelof electrostaticrepulsionbetweenpackingand polymercontributesto lessaccessiblepore volumeand lowerelutionvolumes. This type of effect has been previouslymeasuredusingon-linedifferentialviscometrydetectionfor cationicpolymers(7). This is the firstreporteduse of MALLS detectionfor distinguishingelectrostaticeffectsoncationicvinylamine-basedpolymers.

The variationof ionicstrength (salt concentration)has a dramaticeffectontheRMS radiusof the PVAm-HCIas shown in Figure 11. As the salt concentrationincreases,the RMS radiusdropsaccordingly.The increased salt concentrationof the mobilephase contributesto suppressionof intramolecularscreeningandrepulsiveeffectsof the cationicPVAm-HCI, resultingina decreasedhydrodynamicsize. A poly(vinylalcohol-vinylamine)-HCIcopolymer(PVA-VAm-HCI),which containsapproximately6 molepercent of vinylaminepresentas thehydrochloridesalt, is also shown in Figure 11 for comparativepurposes. It

i

77

exhibits a less dramatic drop in the RMS radius as ionic strength increasesdueto the lower level of ionicchargealong the polymerbackbone.

Knowing the molecular weight and RMS radiusat a given ionicstrength,permitsthe examinationof polymerconformation. At 0.008 M and 0.02 M, theconformationalcoefficient,cz,for the cationicPVAm-HCIexhibitsnearly identicalvaluesof 0.50 and 0.49, respectively. This suggestsa randomcoil, whichisconsistentwith the expectedconformationat levelsof low ionicstrength. At thehigherionicstrength,0.20 M, c_= 0.27. This representsa tightly-coiled,spherical configurationof the polymer. The suppressionof intramolecular,electrostaticscreeningeffects are expectedto yield this type of conformation.However,the lowvalue for o_(less than the theoreticalvalue of 0.33 for asphere) raisesthe questionas to the validityof this result. Lowvaluesforconformationalcoefficientshave been reportedbranchedpolymers(2) andchitosans(8). However,our resultssuggestthat further investigationiswarranted to betterunderstandthese effects.

Characterization of Cationic Poly(vinylamine) using the Mini-Dawn

The Wyatt TechnologyMini-DawnMALLS detectorhas been usedto measuremolecularweight and RMS radiusof bothcationicpoly(vinylamine)homopolymersand copolymers. A chromatogram(detector angle = 45°) of aPVAm-HCI homopolymeris shownin Figure 12 usinga mobilephaseof 0.05 Msodiumnitratewith 0.1% TFA. A low degree of excessbaselinescatter is readilyobservedas was the case withthe Dawn-F at lowscatteringangles. This type ofbehavioris a necessaryprerequisitefor accuratecalculationof molecularweightand RMS radiusvaluesdue to the use of onlythreeangles of detectioncompared to 15 anglesfor the Dawn-F. This pointis further illustratedin Table 3by a comparisonof molecularweightsobtainedfromthe Mini-Dawnand Dawn-Ffor a PVAm-HCIand twoPVA-VAm-HCIcopolymers. Excellentagreementisobservedfor molecularweightusingthe twodetectors. These data illustratethehighdegree of accuracypossiblewiththe use of onlythree angles of detectionfrom Debye calculationsfor molecularweight. For these measurements,thedn/dcvaluesof PVAm-HCIand PVA-VAm-HCIwere determinedat 690 nmandare summarizedinTable 4. PVAm-HCIexhibitsa highvalue for dn/dccomparedto PVA-VAm copolymer. This translatesintomore intenselightscatteringsignalsfor cationicPVAm-HCIunderthese conditions.

With an accuratemeansto measure the molecularweightof PVAm-HCI,a directcomparisonto the molecularweightof the starting PEF is now possible. Figure13 illustratestwo molecularweightdistributions:a PEFwith Mw = 147,000 fromthe Dawn-F andthe correspondingacid hydrolyzedPVAm-HCIfromthe Mini-Dawn. If all the hydrolyzablesiteson the PEF shown in Figure 13 wereconvertedto the pendant-NH3HCI, then a molecularweight of 164,000 daltons

78

Table 3

Molecular Weight Comparisonof Cationic Polymersfrom the Mini-Dawnandthe Dawn-F

(Dawn-F values in italics)

Mw Mn Mw/Mn

PVam-HCI 95,000 56,100 1.7102,000 59,900 1.7

PVA-VAm-HCI 123,000 69,400 1.8120,000 67,300 1.8

PVA-VAm-HCI 104,000 61,600 1.7101,000 59,500 1.7

Table 4

SpecificRefractiveIndexValues for CationicPolymersat 690 nm

Polymer dn/dc, ml/g

PVAm-HCI 0.214PVA-VAm-HCI 0.162

would be expected for the PVAm-HCI. In actuality,we measure a molecularweightof 134,000 daltons. These data can be explainedin twoways. First,only82% of the PEF siteswere hydrolyzed,and second,there existsa looseassociationof someof the chloridecounterionswiththe poly(vinylaminebackbone). The firstexplanationis notconsideredvalidsince itwas determinedfromcarbon-13 NMR analysisthat thisparticularPEF was fullyconverted toPVAm-HCI via acid-hydrolysis.Thus, the possibilityexiststhat all thecounterionsmay not be totallyincludedinthe calculationof molecularweightdue to electrostaticrepulsioneffects or looseassociationwiththe ammoniummoietyon the polymerbackbone. Further investigationsare pending.

RMS radiusvalues determinedfrom the Mini-Dawncan be usedto ascertainionicstrengtheffects,as was previouslydescribedfor the Dawn-F. Figure14 is

a plot of RMS radius versus sodium nitrate concentration for a PVAm-HCIhomopolymer, a PVA-VAm-HCI copolymer and a nonionic PVA. The RMSradius for the PVAm-HCI and PVA-VAm-HCI exhibit the expected decrease withincreasing ionic strength. The PVA-VAm-HCI decreases less than the PVAm-HCI due to the lower amount of cationic charge compared to the PVAm-HCIhomopolymer. The PVA exhibits virtually no change in RMS radius due to itsnonionic character. These data demonstrate the sensitivity of MALLS detectionwith the Mini-Dawn to changes in hydrodynamic size.

Summary

AqueousSEC-MALLS is a powerfultechnique for the characterizationof aminefunctionalpolymersbecausebothmolecularweightand hydrodynamicsize canbe directlymeasured. Molecularweightshave been measuredfromless than50,000 to over 1,000,000 daltons. Our studiesshowthat PEF exhibitsa randomcoil configurationconsistentwiththose of otherwater-solublepolymerssuch aspoly(ethyleneoxide),poly(sacchadde),and poly(vinylalcohol). The RMS radiusof cationicPVAm-HCIand cationicPVA-VAm copolymersis stronglydependenton the ionicstrengthof the mobilephase and can be measuredusingthe Dawn-F (15 angles of detection)orthe Mini-Dawn (threeangles of detection). SEC-MALLS shouldproveusefulfor characterizing molecularweight, size, andconformationof varioustypes of otherwater-solublepolymers.

Acknowledgment

The author wishesto thankAir Productsand ChemicalsInc. for permissiontopublishthis work.

8O

References

1. Vinamer_ Product Bulletin, Air Products and Chemicals, Inc., 1992.

2. P.J. Wyatt, Analytica Chimica Acta, 272, 1 (1993).

3. Wyatt TechnologyASTRA SoftwareManual for Dawn-F.

4. P. Kratochvil, Classical Light Scattering from Polymer Solutions, 1stEdition, iElsevier,Amsterdam, 1987. i

I.5. P. Flow, Principlesof PolymerChemistry,1st. Edition,Comell University

Press, Ithaca, New York, 1981.

6. W.S. Bahary, M. P. Hogan, InternationalGPC Symposium,June 1994,Orlando,FL.

7. D.J. Nagy, D. A. Terwilliger,J. LJq.Chrom., 8, 1431 (1989).

8. R.G. Bed, J. Walker, EoT. Reese, J. E. Rollings,Carbohy. Res., 238, 11(1993).

8]

N-ETHENYLFORMAMIDE MONOMER

H2C _ CHI

NH

HC _OOOFO

m Precipitation Polymerization

= Aqueous Solution Polymerization

m Inverse Emulsion Polymerization

FIGURE 1 It

AMINE-FUNCTIONAL POLYMER SYNTHESIS

__.=o_,_. 1NH2OH n

- -_H2C = CH - - H=C-CH POLY(VINYLAMINE)I PVAmH I. NH

,oo HC=O HC=O

- - n H2C_CH

L " NH_CI• nNEF POLY(ETHENYLFORMAMIDE)POLY(VINYLAMINE)•HCl

PEF PVAm-HCI

FIGURE 2

EXPERIMENTAL SETUP

SOLVENTRESERVOIR

MALLSWATERS 150C GPC _ PHOTOMETER

L (TSK-PW COLUMNS)SAMPLES IN (AUTO INJECT)

m_mmn

ASTRA; EASI, F_ASTRETTE -JI-_A _ I/

so_w_ II_-_/

WASTECOLLECTION

COMPUTER

RGURE 3

SPECIFIC REFRACTIVE INDEX INCREMENTdn/dc

488 nm, 0.05 M SODIUM NITRATE

PVA PEF

0.180 0.180

0.170 -- 0.170O') 13')

t_ v W v

"_ 0.150 --0.150

0.140 - 0.140 --

0.130 ,,,I,,,I=,,I,=, 0.130 ,,,I,,,I,,,I,,,0 1.0 2.0 3.0 4.0 0 1.0 2.0 3.0 4.0

CONCENTRATION, mg/ml CONCENTRATION, mg/ml

dn/dc = 0.150 ml/g dn/dc = 0.155 ml/g

FIGURE 4

MALLS CHROMATOGRAMS OF PEF

Signal, mv

ooo_

45

67

B9

tOtt

Detector No.

t6

Elution Volume, mlri

RGURE 5

MOLECULAR WEIGHT DISTRIBUTIONS OF PEF

L Mw = 1,605,000O)..£ 1.5"o Mw = 43,400 Mw = 293,000

Z0 1.o

0.5

W

0.01.0e + 3 1.0e + 4 1.0e + 5 1.0e + 6 1.0e + 7

MOLECULAR WEIGHT

FIGURE 6

•1 .........

--''''"le

PEFRMS RADIUS vs. MOLECULAR WEIGHT

100.0

f

oo O 10.0o_ Z I

<l:IJLI

p- IJl145,000O - 'V'w

O _ =0.51n"

1.0 I I I JllJlJ i I = Illl=J I i I Jill=1.0e+ 4 1.0e+ 5 1.0e+ 6 1.0e+7

MOLECULAR WEIGHT

FIGURE 7i

CALCULATION OF PEF MOLECULAR WEtGHT 1_dnldc Method

Calculated Mass = 0.59 mg Theoretical Mass = 0.57 mgi i

il.tilB Mw = 28,900 _ _ 90° MALLS

Volts _ n = 15, 0 . RI

OO

II .BSil

.....:9, , , I , , , I , , ,, I , , , I ,

28 3B 40 50 6BElutionVolume,ml

FIGURE 8

CHROMATOGRAMS OF PVAm-HCIFROM DAWN-F

Mw = 102,000 Mn = 60,800 RMS = 24.3 nm

_,_ 90° MALLS0.200

Volts / / _,\-9_--- RI

_OO

El.100

0 000 ---'--;......... '.',,,,, i,,,, t,,,, I I

5.08 7.50 t.0.06 t2.50

EluUon Volume, ml

FIGURE 9

MOLECULAR WEIGHT VS. ELUTION VOLUMEPVAm-HCI

1. Oa+7 -

Molecular -Weight _

0.02 M NaNO 3

1. OR+6 - /,,o

-.o.+. - Salt /No -

1.o=+4 , , ,, I , , ,, I , , ,, I , , ,, I. , , ,6.0 '7.0 B.O 9.0 10.0 11.0

Elution Volume, ml

FIGURE 10

RMS VS. IONIC STRENGTHFOR CATIONIC POLYMERS

I

34

PolymerType32 -a- PVAm. HCl,Mw= 95,000

30 _ PVA-VAm•HCI,Mw= 104,000

28o

IJ

RMS, nm 26

24

22

2O

18 ' ' ' ' ''"' ' ' ' ' '''" ' ' " ' ''"0.001 0.010 0.100 1.000

MOBILE PHASE IONIC STRENGTH, mole/liter (pH = 2.5)

FIGURE 11

" " "" ....... 7

CHROMATOGRAM OF PVAm-HCIFROM MINI-DAWN

690 nm, 45° Detection

I_. see -

D

m

.48e

B. 38em

e.2e. , I , , , , I , , , , I , , , , I5. ee 7.5B te. ee t2.51a

Elution Volume, ml

FIGURE 12

MOLECULAR WEIGHT COMPARISON OF PEFAND CORRESPONDING PVAm-HCI

t. 2i H�PVAm,HCl PEF

Weight Mw = 164,000 (Theor.) Mw = t47,000Fraction Mw = 134,000 (Measr.)

13. OQ--t 'X_

,,,o

4. OQ--'JL

0. Oi 4-0t. Oe-I-_ "JL.Ore x�t.Ore x�'JL.Oe x�tL.Ore %Molecular Weight

FIGURE 13

RMS RADIUS VS. IONIC STRENGTHFROM MINI-DAWN

40

--D- PVAm-HCI

35 _ _ PVA-VAm-HCI

30

RMSRadius,nm 25 . .

20

15

10 "• i ! ! | i i i I i ! • • i ! • i I i i ! i ! Ii i !

0.001 0.01 0.1 1

Sodlum Nltmte Concentratlon, moleslllter (pH= 2.5)

FIGURE 14