Preparation and Characterization of Antibacterial Polypropylene Meshes with Covalently

17 Pages·2017·4.85 MB·English

polymers
Article
Preparation and Characterization of Antibacterial
Polypropylene Meshes with Covalently Incorporated
β-Cyclodextrins and Captured Antimicrobial Agent
for Hernia Repair
NoorSanbhal1,2,YingMao1,GangSun1,3,YanLi1,*,MazharPeerzada2andLuWang1,*
1 KeyLaboratoryofTextileScienceandTechnologyofMinistryofEducation,Room4023,CollegeofTextiles,
DonghuaUniversity,2999NorthRenminRoad,Songjiang,Shanghai201620,China;
[email protected](N.S.);[email protected](Y.M.);[email protected](G.S.)
2 DepartmentofTextileEngineering,MehranUniversityofEngineeringandTechnology,
Jamshoro76062,Sindh,Pakistan;[email protected]
3 DivisionofTextilesandClothing,UniversityofCalifornia,Davis,CA95616,USA
* Corresponding:[email protected](Y.L.);[email protected](L.W.);Tel./Fax:[phone](L.W.)
Received:28November2017;Accepted:5January2018;Published:11January2018
Abstract: Polypropylene (PP) light weight meshes are commonly used as hernioplasty implants.
Nevertheless,thegrowthofbacteriawithintextileknittedmeshintersectionscanoccuraftersurgical
meshimplantation,causinginfections. Thus,bacterialreproductionhastobestoppedinthevery
earlystageofmeshimplantation. Herein,novelantimicrobialPPmeshesgraftedwithβ-CDand
complexeswithtriclosanwerepreparedformeshinfectionprevention. Initially,PPmeshsurfaces
werefunctionalizedwithsuitablecoldoxygenplasma. Then,hexamethylenediisocyanate(HDI)was
successfullygraftedontheplasma-activatedPPsurfaces. Afterwards,β-CDwasconnectedwiththe
alreadyHDIreactedPPmeshesandtriclosan,servingasamodelantimicrobialagent,wasloaded
into the cyclodextrin (CD) cavity for desired antibacterial functions. The hydrophobic interior
andhydrophilicexteriorofβ-CDarewellsuitedtoformcomplexeswithhydrophobichostguest
molecules. Thus,thepreparedPPmeshsamples,CD-TCL-2andCD-TCL-6demonstratedexcellent
antibacterialpropertiesagainstStaphylococcusaureusandEscherichiacolithatweresustainedupto
11and13days,respectively. ThesurfacesofchemicallymodifiedPPmeshesshoweddramatically
reducedwatercontactangles.Moreover,X-raydiffractometer(XRD),differentialscanningcalorimeter
(DSC), and Thermogravimetric (TGA) evidenced that there was no significant effect of grafted
hexamethylenediisocyanate(HDI)andCDonthestructuralandthermalpropertiesofthePPmeshes.
Keywords: antibacterial meshes; guest molecule; cyclodextrin grafting; polypropylene; oxygen
plasma
1. Introduction
Syntheticmesheshavebeenusedwiththeobjectiveofdeliveringlong-termreinforcementtothe
damagedtissuesoftheabdominalhernia[1]. Anabdominalherniaisa“protrusionorrupture”ofan
organthroughtheabdomenwall,causingdefectintheabdomen[2]. Numerousstudiesdemonstrated
that,amongsyntheticmeshes,non-absorbablepolypropylene(PP)warp-knitted,lightweight,andlarge
pore size meshes are the most widely used implants to reduce hernia recurrence [3–7], due to
theirchemicallyinertproperty, lightweight, excellenttissueincorporationability, hydrophobicity,
andstabilitythatcanwithstandamaximumabdominalpressureof170mmHg. Themaindrawback
of these implants is that all synthetic devices favor infection due to the uneven topography of
knitted meshes [8]. Thus, these medical mesh devices are prone to bacteria growth and biofilm
Polymers2018,10,58;doi:10.3390/polym10010058 www.mdpi.com/journal/polymers
Polymers2018,10,58 2of17
formation[9,10]. PPmeshinfectionisaserioussurgicalcomplicationandisoneofthemaincauses
ofherniarepairfailure[11]. Themajorityofthebacteriaconcernedinsurgicalwoundinfectionsare
Staphylococcusaureus(SA).Meshinfectionisdifficulttocurewhentheinfectedwoundiscolonized.
Meshinfectionnotonlycausesremovalofinfectedmeshbuthealthcarecostsandrisksofmorbidity
andmortalityarealsoincreasedaftermeshinfection[12].
One way to minimize mesh infection is pre-operative antibiotic prophylaxis or pre-soaking
of mesh in antibiotics during hernia surgery [13]. Nevertheless, PP is a non-absorbable material;
evenafterdecadesofsuchantibiotictreatments,meshinfectionhasremainedamajorproblem[14,15].
Anotherwaytocontrolsurgicalsiteinfection(SSI)maybetodeliveraheavydoseofantibioticsby
injectionsororallyinclinic. However,thedistributionofsuchheavyantibioticdosestothewhole
bodycausesseveresideeffects. Therefore,sustainedreleaseofantibioticsforasuitabledurationmight
bethekeytoavoidingpost-operativemeshinfection[16].
The use of cyclodextrin (CD) in the designed preparation is due to its extraordinary
properties of hydrophilicity, biocompatibility, and efficient sustained captive and delivery nature.
Cyclodextrin monomers like β-CD are renowned as the most accessible cyclic oligosaccharides
with unique properties to form complexes with drug molecules without covalent links in their
hydrophobiccavities. CDscanbecommonlycross-linkedwithvariousreactantsduetotheirchemical
structure,whichcontainsmultiplehydroxylgroups. Thus,theyhavetheadvantageofreactingwith
hexamethylenediisocyanate(HDI)[17].
Triclosanisaprovenantibacterialagentwithpropertiessimilartoantibiotics,withlowsolubility
in water [18]. However, there have been concerns about the use of triclosan in medical devices.
Nevertheless,theapplicationoftriclosanasamodelantimicrobialagentcanstillpresentthedesigned
functionsofthechemicallymodifiedpolymersandtriclosanhasbeenusedtobecapturedintothe
system[19,20].
Inthepast,polypropylenenonwovenimplantdeviceshavebeenfinishedwithcyclodextrinat
a higher temperature and loaded with antibacterial substances for mesh infection prevention [21],
or surface activation of PP devices with atmospheric pressure plasma and subsequent coating of
chitosan/ciprofloxacinhasbeenperformedforfourdaysofantibacterialrelease[22]. Theselectionof
materialtype(lightweightknittedmeshes)isakeyfactorforherniarepairandinlatercaseschitosan
coulddeliverantibacterialpropertiesforalimitedtime.
Coldoxygenplasmaisasuitablesurfacetreatmentprocesstomodifythesurfacesofpolymers
withoutchangingtheirbulkproperties[23]. Thus,low-pressurecoldoxygenplasmatreatmentisone
ofthebestapproachesavailablesofartoincreasetheadhesionandwettabilityofpolymersurfaces[24],
andalsohasgoodreproducibility[25]. GraftingreactionsontoPPfibers’surfacescouldbeintroduced
bysurfaceactivationwithoxygenplasmatochangethechemistryofPPfibers’surfaces,whichcould
alsoincreasethewettabilityandadhesionforgrafting[26]. Overall,thePPsurfaceispronetooxygen
plasmatreatmentsandresultsinC–Hbondcleavage,whichmayleadtotheintroductionofcarboxyl
andhydroxylgroups[27,28].Theseresultssuggestthatlow-pressurecoldoxygenplasmaisaneffective
pretreatmentprocesstomodifythesurfacesofPPfibers. Tothebestofourknowledge,nostudyhas
beenpublishedtograftβ-cyclodextrinontoPPknittedmeshdevicesformeshinfectionprevention.
However,chemicalcovalentconnectionofcyclodextrinontotheinertpolypropylenemeshfibersisa
keystepinthemodificationreactions.
Therefore,theaimofthisstudywastopreparecyclodextrin-graftedPPmeshes,whichcouldmake
complexeswithtriclosananddemonstratesustainedantibacterialreleaseformeshinfectionprevention.
Forthisreason,low-pressurecoldoxygenplasmawasusedtofunctionalizethesurfacesofPPfibersto
createahydroxylorcarboxylgrouponPPsurfacesbeforetwosimplegraftingstepswereperformed.
Inthefirststep,hexamethylenediisocyanate(HDI)reactedwithplasma-activatedPPmeshesandin
thesecondstepCDcovalentlybondedwithPP-HDImeshes. Moreover,graftedCDsampleswere
loadedwithtriclosanforantibacterialreleasedfunction,asillustratedinFigure1a. Characterization
of modified PP meshes such as surface morphology, element analysis, and structural, thermal,
Polymers 2018, 10, 58 3 of 17
Polymers2018,10,58 3of17
Energy Despersive X-ray spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR), X-
aranyd dhiyfdfrraocptohmiliectietyr w(XeRreDi)n, vdeisffteigreantetdialu ssicnagnnscinagn ncianlgoreimlecettreorn (DmSicCr)o,s acnopdy T(hSeErMm)o,gErnaevrigmyeDtreics p(TerGsiAv)e.
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ptrriocploesratnie.s Mweorreeoavsseer,s smedoudsifiinegd aPsPu itmabelsehs udsetvaiinceesd pefrfiocvaicdyedte spt.roTlhounsg,erde suanltds sshtoawbleed atnhtaitmCicDrowbiaasl
spurcocpeesrstfiuesll ywgitrhaoftuetd aoffnetcotinthge tshuer ofarcigeisnoafl PpPrompeersthieess oafn PdPc ampetushre ddetvriiccelos,s awnh.iMcho croeouvlde rb,em uosdeidfi eind tPhPe
mpreesvhendteivoinc eosf pmroesvhid iendfepctrioolno.n gedandstableantimicrobialpropertieswithoutaffectingtheoriginal
propertiesofPPmeshdevices,whichcouldbeusedinthepreventionofmeshinfection.
.

Figure 1. (a) Illustrations of experimental design for β-CD grafted antibacterial surgical PP meshes;
Figure1. (a)Illustrationsofexperimentaldesignforβ-CDgraftedantibacterialsurgicalPPmeshes;
Schemes (b) step-1, PP-HDI grafting; (c) step-2, PP-HDI-CD grafting; and (d) triclosan loaded meshes.
Schemes(b)step-1,PP-HDIgrafting;(c)step-2,PP-HDI-CDgrafting;and(d)triclosanloadedmeshes.
Polymers2018,10,58 4of17
2. MaterialsandMethods
2.1. Materials
Polypropylene(PP)warp-knittedmesh,madeoffinediameter(0.1mm)monofilamentwithalarge
poresize(3.5mm×2.5mm)andlightweight(27g/m2),wasreceivedfromNantongNewtecTextile
andChemicalFiberCo. Ltd.,Nantong,China. Forwatercontactanglemeasurement,aPPnonwoven
melt-blownfabricof23g/m2wasnselected.Hexamethylenediisocyanate(HDI)(≥98%)CAS:822-06-0
and β-Cyclodextrin (CD) (≥97%) CAS: 7585-39-9 was purchased from Sigma Aldrich, Shanghai,
China. Triclosan CAS: 3380-34-5 was purchased from Aladdin Company Shanghai, China, while
N-Ndimethylformamide(DMF)CaseNo. 68-12-12wasreceivedfromShanghaiLingfengCompany.
Ethanol(≥99.7%)waspurchasedfromYangyuanChemicalEngineering,Changshu,Jiangsu,China.
2.2. Methods
2.2.1. ColdPlasmaSurfaceFunctionalization
Acoldplasmamachine(HD-300)atlowpressurewasusedforthesurfacefunctionalizationofPP
meshsamples. ThemachineisconsistedofPower(500W),radiofrequency(13.56MHz)ofplasma
andavacuumreactionchamber(300cm×300cm)forthetreatmentofsamples. AllPPmeshsamples
(10cm×10cm)weresurfaceactivatedatconstantpowered(40W)andpressure(10pa)ofoxygengas.
Moreover,optimizedtreatmenttime(300s)wasselectedforallsamples.
2.2.2. TwoGraftingStepsandPP-HDI-CDIncorporation
PlasmatreatedPPmesheswasgraftedwithβ-cyclodextrinsbysimpletwograftingstepmethod.
First HDI (2–6%) was reacted with the plasma treated samples. Afterwards, the surface modified
PP-HDI samples were further reacted with CD (2–8%). For both processes the liquor ratio was
(mesh:solution)1:100.Thetimeandtemperaturewere30–90minand65–85◦C,respectively.Afterward,
thePPsurfacemodifiedmeshes(HDI-CD)werewashedseveraltimeswithwarmdistilled(50◦C)
watertoeliminateresiduesofunconnectedchemicalbeforedrying. HDIgraftedPPsampleswere
namedPP-HDI-2(2%),PP-HDI-4(4%),PP-HDI-6(6%)andCD-HDImodifiedpolypropylenemesh
sampleswererespectivelynamedasHDI-CD-2(2%),HDI-CD-4(4%),HDI-CD-6(6%),andHDI-CD-8
(8%)accordingtotheCDsconcentrationsinthesolutions.
2.2.3. LoadingofTriclosan
Cyclodextrin (HDI-CD)-modified samples (0.5 g) were immersed in the 50 mL mixture
(70% ethanol and 30% water) containing 0.6% (0.3 g) triclosan as a guest molecule. All samples
weresoakedfor24hbeforedrying. Themodifiedpolypropylenesamplesaftertriclosanloadingwere
namedasCD-TCL-2,CD-TCL-4,andCD-TCL-6,andCD-TCL-8,respectively.
2.3. CharacterizationTechniques
2.3.1. SEMandEDX
Acoatingmachine(E-1045,Hitachi,Tokyo,Japan)wasfirstusedtocoatuntreatedandmodified
samples with platinum (pt.) ion. Subsequently, all coated samples were tested by a scanning
electronmicroscope(JEOLJSM6330,Tokyo,Japan)andEnergyDespersiveX-rayspectroscopy(EDX)
(OxfordInstrumentISIS300,Oxfordshire,UK)connectedwithSEM.
2.3.2. FTIR
ChemicalcompositionsofuntreatedandmodifiedsamplesweremeasuredbyaFourierTransform
InfraredSpectroscopy(FTIR)AttenuatedTotalReflectionmode(ATR)(Nicolet6700,DownersGrove,
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IL,USA).Allsampleswerecharacterizedwithresolutionof4.0cm−1andwavenumberrangingfrom
500to4000cm−1.
2.3.3. ContactAngle
Duetothefinefilamentdiameter(0.1mm)andlargerporesizeofthePPmeshes,anonwoven
PP was preferred as a model fabric to reflect the differences between the contact angles of the PP
control and the modified meshes. Two methods, captive bubble (static contact angle) and sessile
drop(dynamiccontactangle),wereusedtomeasurethewatercontactangle,usingWCA20software
to estimate the hydrophilic/hydrophobic behavior of samples. A Teli CCD camera (Data physics
instrument,SanJose,CA,USA)wasusedtocaptureimagesofwatercontactangleandatleastfive
dropsof5µLforeachsamplewereaddedtogetanaveragecontactangle.
2.3.4. XRD
Powders of PP control and modified samples were prepared for X-ray diffractometer (XRD)
examination. AnXRDmachine(RigakuD/MAX2550/PC,Tokyo,Japan)wasusedforscanningrate
of0.02/minat40kV,200mAandarangeof0◦–60◦ (2θ)tocharacterizeallsamples.
2.3.5. ThermalAnalysis
PPcontrolandmodifiedmeshsampleswerescannedonadifferentialscanningcalorimeter(DSC)
(PerkinElmer4000,DownersGrove,IL,USA)atarateof20◦C/minovertherangeof20–250◦C;
thecoolingratewassetto20◦C/min.
Thermogravimetric analysis was conducted to evaluate the percentage residual weight loss
of PP control and modified samples. A Perkin Elmer thermogravimetric analyzer (TGA) 4000
(DownersGrove,IL,USA)devicewasusedtoscanallsamplesoveratemperaturerangeof250–550◦C
at30 ◦C/min. Thus, nitrogengaswasusedataflowrateof20mL/minwithapressureof2bars
duringcharacterization.
2.3.6. AntibacterialActivityAssessment
AgarDiffusionTestMethod(QualitativeAnalysis)
Antibacterial activity was conducted using the agar diffusion test method described in a
previouslypublishedresearchpaper[16]. First, 400µLofbacterialsuspension(1 × 108 CFU/mL)
(StaphylococcusaureusATCC25923andEscherichiacoliATCC25922)wasevenlyspreadontotheagar
platewiththehelpofpre-sterilizeddisposableswabs. Then,PPcontrolandmodifiedsamplesofsize
1cm×1cmwereplacedonanagarplateandincubatedfor24hat37◦C.Thezoneofinhibitionof
incubatedsampleswasmeasuredwithadigitalverniercaliperinfourdirectionsandreportedasthe
meanvalue. Thezoneofinhibitiondiameterwasmeasuredbythefollowingformula:
L=(D−T)/2
whereL=zoneofinhibition,T=diameteroforiginalsample,andD=inhibitionzonediameterafter
24hincubation.
SustainedEfficacyTest(SerialPlateTransferTest)
TheobjectiveofthistestwastoevaluatetheantibacterialactivityofCD-graftedsampleswith
referencetotheantibacterialreleasetimeindays. Aftereach24h,theagarplatewaschangedand
meshsamples(1cm×1cm)weretransferredtoanewagarplatecontainingsimilarcolonyforming
units(1×108 CFU/mL)ofbacteria(StaphylococcusaureusATCC25923andEscherichiacoliATCC25922)
aftercontactwiththepreviousone. Thetestwascontinueduntilmodifiedmeshessustainedtheir
antibacterialactivity.
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2.3.7. StatisticalAnalysis
The data in the figures are described as mean and standard deviations. However, the error
barsinthefiguresindicatestandarddeviations. ANOVAone-wayanalysis(single-factor)wasused
to determine the differences between each sample and the data in the figures are labeled, such as
p<0.001(***),p<0.01(**),andp<0.05(*). Althoughapvalueof(*)<0.05wasconsideredasthe
confidenceinterval,varianceswerefirstconfirmedtobesignificant.
3. ResultsandDiscussion
3.1. CyclodextrinGraftingandLoadingofTriclosan
The grafting of β-cyclodextrin (CD) onto the PP fibers was achieved by a two-step reaction,
asshowninFigure1. Beforegrafting, low-pressureoxygenplasmawasusedtocreateahydroxyl
grouponthesurfacesofthePPmeshes. Afterward,twograftingstepswereperformed. Infirststep
hexamethylene diisocyanate (HDI) was reacted (Figure 1b) with the plasma-treated PP fibers and
theninsecondstepPP-HDIsampleswerefurtherreactedwithhydroxylgroupsofβ-CD(Figure1c).
However,cyclodextrinsarewellsuitedtoformcomplexeswithtriclosan. Thus,triclosanwasloaded
(Figure1d)intoHDI-CDgraftedsamples.
The process parameters, reaction time, and temperature of the cyclodextrin grafting reaction
(Figure2)wereoptimized. TheeffectoftemperatureonCDgrafting(Figure2a)indicatesthatweight
%increasedwithanincreaseintemperaturefrom65to75◦C.However,anadditionaltemperature
increasefrom75to85◦Cdidnothaveanyeffectontheweightsofthetreatedsamples.Graftingreaction
timewasalsooptimized,asillustratedinFigure2b,andthegraftedweightoftheproductsincreased
withanincreaseinreactiontimefrom30to60min. Thus,atemperatureof75◦Candtimeof60min
were considered the optimum conditions for HDI and cyclodextrin grafting. Moreover, Figure 2c
displaysthetotalweightincreaseforHDI,CD,andtriclosan. HDI(6%)showedbetterresultsforthe
graftingreactionontothePPmeshesanddemonstratedatotalweightincreaseof1.63%.AllCD-grafted
samples were treated with the same concentration of HDI. However, it was difficult to find the
real increased weight of the HDI samples due to the fact that PP-HDI samples were advanced to
the second step of CD grafting without washing to save the unreacted diisocyanate group on the
HDI-treated PP surface. The average weight increases of CD grafting for HDI-CD-2, HDI-CD-4,
HDI-CD-6,andHDI-CD-8were5.130%,6.410%,7.27%,and7.17%,respectively. Nevertheless,after
triclosanloadingtheaveragecorrespondingweightincreasedto2.025%,2.268%,2.414%,and2.40%,
respectively.HDI-CD-6wasconsideredthebestsample,whichgainedmoreweightofCDandtriclosan.
Thus, CD-HDI-6 and CD-TCL-6 samples were included in further testing. Moreover, PP meshes
withoutplasmatreatmentwerealsousedforHDIgrafting,butunfortunatelywedidnotsucceedwith
HDIgrafting. Therefore,plasmatreatmentwaskeytoincreasingthesurfaceroughnessofPPmeshes
forbettergraftingofHDI.
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((cc)) wweeiigghhtt iinnccrreeaassee %% ooff HHDDII--CCDD--TTCCLL ssaammpplleess.. DDaattaa ooff eeaacchh ssaammppllee eexxpprreesssseedd aass aavveerraaggeess ((nn == 33))..
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Polymers2018,10,58 8of17
Polymers 2018, 10, 58 8 of 17

Figure 3. SEM micrographs; (a1,a2) PP control; (b1,b2) oxygen plasma treated; (c1,c2) HDI grafted
Figure3. SEMmicrographs;(a1,a2)PPcontrol;(b1,b2)oxygenplasmatreated;(c1,c2)HDIgrafted
PP-HDI-6; (d1,d2) HDI-CD-6; and (e1,e2) CD-TCL-6 (top row 200×, bottom row 1000×).
PP-HDI-6;(d1,d2)HDI-CD-6;and(e1,e2)CD-TCL-6(toprow200×,bottomrow1000×).
3.3. Characterization of HDI, CD, and Triclosan on Modified PP Mesh
3.3. CharacterizationofHDI,CD,andTriclosanonModifiedPPMesh
The PP control and grafted samples were characterized using EDX (Figure 4) for elemental
The PP control and grafted samples were characterized using EDX (Figure 4) for
analysis.
elementalanalysis.
Polymers2018,10,58 9of17
Polymers 2018, 10, 58 9 of 17

Figure4.EDXspectraandatomicpercentofPPcontrolandmodifiedmeshes(a)PPcontrol;(b)HDI
Figure 4. EDX spectra and atomic percent of PP control and modified meshes (a) PP control; (b) HDI
grafted,PP-HDI-6;(c)HDI-CD-6;(d)CD-TCL-6.
grafted, PP-HDI-6; (c) HDI-CD-6; (d) CD-TCL-6.
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tthhee ssaammee ccaarrbboonn ((CC)),, ooxxyyggeenn ((OO)),, aanndd nniittrrooggeenn ((NN)) ((FFiigguurree 44cc)) bbuutt aatt ddiiffffeerreenntt ppeeaakk hheeiigghhttss,, wwhhiicchh
ccoonnfifirrmmeedd tthhee pprreesseennccee ooff ccyyccllooddeexxttrriinn.. IItt ccaann bbee oobbsseerrvveedd tthhaatt CCDD--TTCCLL--66 sshhoowweedd ((FFiigguurree 44dd)) aann
aaddddiittiioonnaall ppeeaakko offc hclholroinrien(eC (lC)al)t oamtomwi twhiinth3i.n0 3k.e0V kienVa dind iatidodnittoiocna rtboo cna,rnbiotrno,g nenit,roangdeno, xayngden oaxtyogmesn,
caotonmfirsm, cionngftihrmeisnugc ctehses fsuulclcoeasdsfiunlg looafdtriincglo osaf ntroicnlotosatnh eoCntDo -tghrea fCteDd-gsaramftpelde ss.amples.
SSttrruuccttuurreess ooff tthhee PPPP ccoonnttrrooll,, PPPP--HHDDII,, aanndd HHDDII--CCDD--ggrraafftteedd ssaammpplleess aatt ddiiffffeerreenntt rreeaaccttiioonn ssttaaggeess
wweerree aannaallyyzzeedd uussiinngg FFTTIIRR--AATTRR.. TThhee PPPP ccoonnttrrooll eexxhhiibbiittss aabbssoorrbbaannccee bbaannddss aatt 22995500 ccmm−−11 ((vvaa CCHH33)),,
22991166 ccmm−−1 1(v(av aCHCH2)2, )1,415425 c2mc−m1 (−δC1 H(δ3C)H, a3n)d, a1n3d761 c3m76−1 c(mδC−H13()δ C[2H9,33)0][.2 N9,e3v0]e.rtNheelveesrst, haelll ePsPs-,HaDllIP gPr-aHftDedI
gsaramftpeldess (aFmigpulrees 5(aF)i gsuhroew5ead) asdhdowitieodnaald adbistoiorbnaanlcaeb spoerabkasn acte 3p32e1a kcsma−t1 (3O32H1),c 1m62−01 c(mOH−1 )(,ν1 C6=2O0)c,m an−d1
(1ν57C6= cOm)−,1 a(δnNdH15) 7d6uec mto− h1y(dδrNoxHy)l,d aumeidtoe Ih, yadnrdo axmyli,daem IIi dfoermI,aatniodnas,m reidspeeIcItifvoerlmy.a CtiDon-gsr,arfetsepde (cFtiigvuelrye.
C5bD) -pgroalyftpedro(pFyigleunree s5abm)ppolelysp mroapinytlaeinneesda mallp plersevmioaiunst apienaekdsa ollf pHreDvIi-ogurasfpteedak ssaomfpHleDsI a-gnrda fatedddistaiomnpallelys
showed absorbance peaks at 1701 cm−1 (carbonyl group, ν C=O) and C–H (vCH) stretch at 1256 cm−1.
However, C–O groups of CD also appear at 1030 cm−1, consistent with a previously published paper
Polymers2018,10,58 10of17
andPoalydmdeirtsi 2o0n1a8,l l1y0, s5h8 o wedabsorbancepeaksat1701cm−1 (carbonylgroup,νC=O)andC–H(vC1H0 o)f 17
stretch at 1256 cm−1. However, C–O groups of CD also appear at 1030 cm−1, consistent with a
pre[v3i1o]u. sTlyhep aubbsloisrhbeadncpea bpaenrd[3 o1]f. aTmhiedaeb Is o16rb20a nccme−b1 a(nν dCo=fOa)m aindde aIm16id20e cIIm 1−5176(ν cmC=−1O (δ)NanHd) acmanid beeI aIlso
157o6bcsmer−v1ed(δ NinH al)l cCanD-bgeraafltseodo sbasmerpvleeds, iwnhailclhC Dco-ngfriarfmteedds tahme pfolerms,awtihoinch ocf ounrfietrhmaende, tchoenfsoisrmtenatti wonitohf the
ureltihtearnaet,ucroen osins tCenDt w[1i7t,h32th].e Mlioterreaotvuerer, owneC dDid[ 1n7o,3t2 f]i.nMd oarneyo vaebrs,owrbeadnicde npoetafikn ddifafneryeanbcseosr bbeatnwceeepne aHkDI-
diffCerDe n(CceDs-bgertawfteeedn) aHnDdI C-CDD-T(CCLD -(gtrriacfltoesda)na-lnodadCeDd)- TsCamLp(tlreisc,l owshainc-hlo ias ddeude) tsoa mthpe lfeasc,tw thhaict htriiscldousaent owas
thenfaoct trtehaacttetdri cbluots acnapwtuarsendo btyre tahcet eCdDb ucatvciatpyt. uredbytheCDcavity.

Figure5. FTIR(ATR)spectra; (a)PP-HDIgraftedsamples(PP-HDI-2), (PP-HDI-4)andPP-HDI-6;
Figure 5. FTIR (ATR) spectra; (a) PP-HDI grafted samples (PP-HDI-2), (PP-HDI-4) and PP-HDI-6; and
and(b)PPcontrol,PP-HDI-6-grafted,andtriclosan-loaded(CD-TCL-2andCD-TCL-6)samples.
(b) PP control, PP-HDI-6-grafted, and triclosan-loaded (CD-TCL-2 and CD-TCL-6) samples.