Preparation and Characterization of Polyurethane Nanocomposites Using Vietnamese Montmorillonite...

Research ArticlePreparation and Characterization of PolyurethaneNanocomposites Using Vietnamese MontmorilloniteModified by Polyol Surfactants

C N Ha Thuc12 H T Cao3 D M Nguyen1 M A Tran1 Laurent Duclaux2

A-C Grillet4 and H Ha Thuc5

1 Department of Polymer and Composite Materials Faculty of Materials Science University of ScienceNational University of HCM City (VNU-HCM) Ho Chi Minh City 70000 Vietnam

2 Laboratoire de Chimie Moleculaire et Environnement Polytechrsquo Annecy-Chambery Universite de Savoie73370 Le Bourget du Lac Cedex France

3 Department of Magnetic and Biomedical Materials Faculty of Materials Science University of ScienceNational University of HCM City (VNU-HCM) Ho Chi Minh City 70000 Vietnam

4Laboratoire de LOCIE Polytechrsquo Annecy-Chambery Universite de Savoie 73370 Le Bourget du Lac Cedex France5 Department of Polymer Faculty of Chemistry University of Science National University of HCM City (VNU-HCM)Ho Chi Minh City 70000 Vietnam

Correspondence should be addressed to C N HaThuc htcnhanhcmuseduvn

Received 6 September 2013 Revised 11 December 2013 Accepted 11 December 2013 Published 16 March 2014

Academic Editor Sheng-Rui Jian

Copyright copy 2014 C N HaThuc et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This study focuses on the preparation of thermoplastic polyurethane (TPU) nanocomposite using Vietnamese montmorillonite(MMT) as the reinforced phase The MMT was previously modified by intercalating polyethylene oxide (PEO) and polyvinylalcohol (PVA) molecules between the clay layers X-ray diffraction (XRD) results of organoclays revealed that galleries of MMTwere increased to 182 A and 27 A after their intercalation with PEO and PVA respectively Thermoplastic polyurethane (TPU)nanocomposites composed of 1 3 5 and 7wt organoclays were synthesized The result of XRD and transmission electronmicroscopic (TEM) analyses implied that the PEO modified MMT was well dispersed at 3wt in polyurethane matrix FourierTransform Infrared Spectroscopic (FTIR) has confirmed this result by showing the hydrogenous interaction between the urethanelinkage and OH group on the surface of silicate layer Thermogravimetric (TG) showed that the organoclay samples also presentedimproved thermal stabilities In addition the effects of the organoclays on mechanical performance and water absorption of thePU nanocomposite were also investigated

1 Introduction

Polyurethane (PU) is a versatile polymeric material withdesirable properties for example high abrasion resistancetear strength excellent shock absorption flexibility andelasticity By blending with inorganic fillers its performancehas been improved further Since 1998 PUclay nanocom-posites [1 2] were developed but the good dispersion ofclay being a key parameter in the synthesis of claypolymernanocomposites depends on the clay mineral purity and itsmodification

As an example the purity of a natural montmorillonite(MMT) can be improved by removing the associated gangueminerals such as sand gravel quartz feldspars calcite ironoxides and humic acids which are oftenly co-existed withMMT in natural clay [3ndash6] The purity of the MMT has astrong effect on engineering properties of polymer nanocom-posites especially on elongation and impact resistance [7]Thus the highest purity possible of this kind of filler isrequired for nanocomposite elaboration

The aim of clay modification is to render the layeredsilicatesmiscible with polymermatrices like polyurethane by

Hindawi Publishing CorporationJournal of NanomaterialsVolume 2014 Article ID 302735 11 pageshttpdxdoiorg1011552014302735

2 Journal of Nanomaterials

lowering the surface energy improving the wetting charac-teristics of the polymer matrix and enlarging the interlayerspacing of clay The normally hydrophilic silicate surfaceshould be converted to an organophilic one allowing theintercalation of many engineering polymers After Xiong etal [8] there are two main factors that should be consideredin forming polymerclay nanocomposites firstly the organicmodifier molecules must enter in interlayer galleries inenlarging the interlayer space of MMT and then result theeasier interaction of polymer molecules or monomers andclay layers Generally the modification is processed by ion-exchange reactions with cationic surfactants including pri-mary secondary tertiary and quaternary alkylammonium oralkylphosphonium cations [7 9ndash11] or by intercalation in clayof hydrophilic polymers such as polyethylene oxide (PEO)or polyvinyl alcohol (PVA) [10 12ndash16]

Many researchers studied the PU nanocomposites toimprove the mechanical performance of polyurethane andreduce the production cost [7 10 11]However such approachhas some disadvantages such as the reduction of ductilityand the decrease of water resistance There are very fewreports on TPU composites and nanocomposites preparedby bulk and melt processing [17 18] Recently much efforthas been conducted to find new methods for preparingPUmodifiedMMTWang and Pinnavaia [1] or Zilg et al [19]reported an intercalated PUMMT by in situ polymerizationof Toluene diisocyanate (TDI) and a mixture of polyoland MMT Cheng et al [20] proposed an intercalationmethod in solution as PU prepolymer was inserted intothe MMT intergallery in solution conditions followed by acuring procedure with 14-butanediol To further improve theproperties of PUclay nanocomposites alternate functionalmodifiers which can react with polymer are being used toprepare polymerclay nanocomposites For example in thestudy of Chen et al [21] the authors found exfoliation ofclay layers in PU nanocomposites when clay was treatedby aminolauric acid (12COOH) and benzidine (BZD) sep-arately as shown by X-Ray diffraction patterns and TEMThe mechanical property of polyurethane nanocompositewith benzidine modified clay showed much better than thatof 12-aminolauric acid treated clay and it was explainedby the difference in the interaction between the swellingagent and polyurethane molecular chain 12-Aminolauricacid contained only one terminal ndashNH

2group which might

react with aminute amount of unreacted ndashNCO to formureawhile both of the two terminal ndashNH

2groups in benzidine

could participate in the reaction Therefore cross-linkingstructure can be formed by benzidine and linear chains by12-aminolauric In another study of Tien and Wei [22] theeffect of exfoliation behavior on mechanical properties intethereduntethered PU nanocomposites was investigated byusing 1 2 and 3 hydroxyl groups in the molecules of organictreatment of layered silicates which acted as pseudochainextenders for polyurethane prepolymer X-Ray analysis ofpolyurethane nanocomposites prepared by solution methodconfirmed that with the increase of numbers of hydroxylgroups in quaternary ammonium ions the dispersion oflayered silicates in polyurethanes transformed from an inter-calated to an exfoliated state Later Pattanayak and Jana

[18 23 24] have studied the in situ reaction of polyurethanenanocomposites with reactive Cloisite 30B through bulkpolymerization Clay-polymer tethering reaction occurredunder conditions of high shear stress by using a conventionalbatch mixer Two processing methods were used in thissynthesis of nanocompositematerials In the firstmethod thechain extender 14-butanediol was added after the additionof clay in the second method the chain extension reactionwas carried out before the addition of clay Unlike the solutionpolymerization method conducted by Tien andWei [22] theaddition of clay before chain extension reaction led to poordispersion of clay particles With the confirmation of FTIRand rheological data the clay exfoliation was found to beinfluenced mainly by strong interaction between modifiedclay and PU chain

Based on the report of these authors about the clay-tethered polyurethane nanocomposites [18 21 22 25] in thepresent study we describe the preparation PUclay nanocom-posites from purified Vietnamese montmorillonite which ismodified via solution method by polyethylene oxide (PEO)and polyvinyl alcohol (PVA) molecules The modifier agentshaving the hydroxyl functional groups are considered to reactwith PU chains as pseudochain extenders for polyurethaneprepolymer Thermoplastic polyurethane nanocompositecomposed of 1 3 5 and 7wt of organoclays were then pre-pared via in situ polymerization from crystalline polypropy-lene glycol (PPG) polyols and 441015840-diphenylmethane diiso-cyanate (14-MDI) using 14-butanediol (14-BD) as chainextenderThis paper describes also themorphology and somebasic properties of the prepared PU nanocomposite

2 Experimental

21 Materials and Chemicals Vietnamese montmorillonite(MMT) minerals (LamDong Mg2+-montmorillonite) wasobtained by purification of bentonite from the Clay MineralsDepository Hiep Phu at the LamDong province (southof Vietnam) using the purification process reported inour previous study [26] The polymers used in this workfor the modification of clay were polyethylene oxide PEO(M119899= 10 000) and polyvinyl alcohol PVA (M

119899= 8700)

from Aldrich Chemical Company Inc For the synthesis ofPU 441015840-diphenylmethane diisocyanate (14-MDI Aldrich)14-butanediol (14-BD Aldrich) and polypropylene glycol(PPG M

119899= 1200 Aldrich) were used as received from

Aldrich Chemical Company The PPG 14-BD and 14-MDIreagents were vacuum dried at 80∘C for 24 h prior to use

22 Preparation of PEO and PVA Modified MMT The clayused was the purified MMT obtained from our previouspurification procedure [26] In the literature two processesare reported for the PEO or PVA intercalation of clay [1213 15] solution intercalation and melt intercalation In thiswork the solution intercalation was performed because itallows intercalating polymers with little or no polarity intolayered structure and facilitates the production of oriented-clay intercalated layer [7 27]

In a typical experiment the selected polymer and silicatewere weighed according to the designated ratio A weighed

Journal of Nanomaterials 3

amount of purified clay (1 g) was dispersed in a knownvolume of polymer solution at 60∘C for 4 hours The solidsample was collected by centrifugation and then washedtwo times with distilled water before keep it in a vacuumoven (sim60∘C)The initial polymer concentrations in aqueoussolution (C

0) were in the range 001 003 and 005M for PEO

and 003 005 and 01M for PVAThe success of intercalation of PEO-MMT and PVA-

MMT samples was checked by X-Ray diffraction (XRD) andthe saturation ratio of polymer intercalated in samples shouldbe determined by differential scanning calorimetry (DSC)

23 Synthesis of PUClay Nanocomposites Polyurethanenanocomposites containing 1 3 5 and 7 content (weightpercent) of modified MMTs were prepared from PEO andPVA modified MMTs (PEO-MMT obtained PEOMMT =031 ratio and PVA-MMT obtained PVAMMT = 1 ratio)For the preparation 40 g of dry PPG were added to astoichiometric ratio of dried modified MMT (MO-MMT)powder in a 250mL flask with a mechanical stirrer atambient temperature Additional mixing was performed viaan ultrasonicator (100W nominal frequency of 35 kHz) atambient temperature and then the mixture was heated to90∘C for 2 h to remove residual water Then 14-MDI wasadded in a molar ratio of 2 1 (relatively to PPG) to themixture of PPG and modified MMT at 80∘C to obtainthe prepolyurethanemodified MMT material after 15 h ofreaction After theNCO-terminated prepolymer was formed3 g of 14-BD were added to the prepolyurethaneMO-MMTunder vigorous stirring for 60 s at 80∘C Dibutyltin dilaurate(002wt) was added to the reacting solution reaction at80∘C and subsequently the prepolyurethaneMO-MMT wasimmediately poured in a metal mold with dimensions of185 times 155 times 2 (cm3) and then cured for 2 h at 80∘C in avacuum oven to form a polyurethane (PU)modified MMTnanocomposite film after demoulding

24 Characterization Techniques

241 X-Ray Diffraction (XRD) The modified MMT werecharacterized by X-Ray PowderDiffraction (WAXRD) Anal-yses were performed at the CuK

1205721radiation by using a Bragg-

Brentano (120579 2120579) mode goniometer (CGR 120579 60) equippedwith an X-Ray generator (INEL XRG 3000) set at 35 kVtension and 30mA current a point proportional detector(4545 LND) and a curve quartz monochromator (curveradius = 250mm)The scanning rate was 002∘s over a rangeof 2120579 = 2ndash20∘ for one-dimensional diffraction XRD patternwere collected from 2∘ to 50∘ (2120579) and performed on orientedsample prepared by the deposit of suspension of clays on glassslide

For the nanocomposite characterization small-angleX-Ray diffraction (SAXRD) experiments were performeddirectly on the film samples which have thickness of 05mmThe measurements were carried out with a Bruker D8advance diffractometer (graphite monochromator usingCu-K1205721

radiation step scan of 002∘ and 1 s per step) in the05ndash10 2120579 rangeThe XRD line profile analysis was performed

with TOPAS P software (Bruker AXS Karlsruhe Germany)using a split pseudovoigt profile function to determine the 2120579position of the 001 reflection The refined profiles were usedfor the determination of reflection positions

242 Transmission Electronic Microscopy (TEM) The sam-ples for the transmission electron microscopy (TEM JEOL3010) study were microtomed using a cryogenic ultramicro-tome system (LeicaUltracutUct) into 50 nm thick slices Sub-sequently 3 nm thick amorphous carbon layer was depositedon to these slices supported on 200-mesh copper nets forTEM observation

243Thermogravimetric Analyses (TGA)The thermal degra-dations of the polymers were observed by thermogravimetricanalysis (TGA) at a heating rate of 10∘Cmin in the tempera-ture range 30ndash12000∘CThe atmosphere used was air and thesample weights were 80ndash100mg

244 Differential Scanning Calorimetry (DSC) The thermaltransitions of polymers were observed by differential scan-ning calorimetry (DSC 2020 of TA instrument) at a heatingrate of 10∘Cmin under nitrogen purge of 30mLmin Thesample sizes were 3ndash10mg in a sealed aluminum pan

245 Dynamic Mechanical Analysis Properties (DMA) Themain features determined in this study are the module E1015840and loss factor (tan120575) of materials DMA was carried outin a tensile mode using a frequency of 5Hz on RheometricScientific RAC 815 de Metravib RDS All tests were carriedout at room temperature

246 Water Adsorption Measurement Water absorptionmeasurement were carried out in a desiccator containing ahigh humidity rate (98water) controlled by CuSO

4solution

and the sample mass uptake was determined as a function oftime

3 Results and Discussion

31 Characterization of the PEOModifiedMMT (PEO-MMT)Figure 1 shows the XRD patterns of the montmorillonitemodified by PEO using solution intercalation at differentPEO content The melt and solution intercalation of thePEOMMT system with different ratio has been discussedcarefully in the studies of Shen et al [12 13] In our study thed001

basal spacings of the obtained hybrid materials increasetogether with increasing PEO content Figure 1 shows a d

001

basal distance sim145 A (2120579sim6∘) for PEOMMT = 01 hybridmaterial with compared to d

001sim10 A for a dry MMT This

distance increases up to d001sim182 A for a fully intercalated

MMT (at PEOMMT = 03 and 05)According to the literature [12ndash14] PEO has the chain

thickness of about 4 A arranged in the interlayer forming themonolayer or bilayer with the zig-zag or spiral conformationThe report is adequate to this study our XRD results showthat the intercalation of PEO monolayer is obtained for thePEOMMT ratios equal to 01 corresponding to the d

001


02000400060008000

1000012000140001600018000

2 6 10 14 18 22 26 30 34 38 42 46

Inte

nsity

(cps

)

Pure MMT

2120579 (deg)

d001 = 18 Ad001 = 182 Ad001 = 118 Ad001 = 145 A

PEO-MMT = 05 1PEO-MMT = 03 1

PEO-MMT = 01 1

Figure 1 X-Ray patterns of PEO-MMT mixtures as a function ofmodifierhost ratios (PEOMMT = 01 03 and 05)

distance sim1380 A and that at the ratios equal to 03 and 05the clay interlayer was expanded to about 17-18 A implyingthat a PEO bilayer insertion has occurred In addition exceptd001

the hk bands (2120579 = 2ndash20∘) of MMT such as d002

(sim10∘) d003

(sim151∘) and d004

(sim20∘) still showed up in thespectra indicating the stability of the layer structure afterthe intercalation of PEO And otherwise the two reflectionsobserved at about 125∘ and 25∘ are characteristic for kaoliniteimpurity which is not intercalated by PEO

DSC characterization of the PEO-MMT complex broughtout the changing of PEO crystalline peaks after reaction withMMT This could be explained by the transformation of thecrystalline PEO into low crystallinity phase inserted intothe MMT galleries Moreover the interaction between theadsorbed PEO and the polar groups on the surface layers ofmontmorillonite has prevented the PEO crystallization

The melting endothermic peak of PEO was nearly unob-served in DSC thermograms (Figure 2) of the PEOMMT =01 modified MMT sample which did not also show crys-talline PEO diffraction lines at 2120579sim21∘ in its XRD spectraThis result may be due to the PEO chains being confined inbetween the layer silicates cannot crystallize In the PEOMMT = 03 and 05 modified MMTs samples the endother-mic peak shown at 40∘C and 63∘C respectively relating tothe melting of the PEO crystallites was observed CrystallinePEO can be formed as well as the excess amount of PEOwhich cannot be intercalated into the clay galleries (from theratio of 03) Themelting temperature of sample is decreasedin comparison with pure PEO melting at about 67∘C whenfewer of the PEO content is used for the modification ofMMT This has been ascribed to disruption of large scalecrystallite formation by the presence of the large amount ofclay

Therefore the XRD and DSC results suggest that thePEO-MMT = 03 ratio almost corresponds to a saturationPEO ratio value of intercalation in MMT Thus this PEOconcentration was chosen for the synthesis of further PUnanocomposites

0

15 25 35 45 55 65 75 85 95 105

115

125

135

145

155

165

175

185

195

Hea

t flow

(mW

)

minus30

minus25

minus20

minus15

minus10

minus5

Temperature (∘C)PEO-MMT (01 1)PEO-MMT (03 1)

PEO-MMT (05 1)PEO

Figure 2 DSC analysis of PEO-MMTmixtures realized by interca-lation in solution method

0

1000

2000

3000

4000

5000

6000

7000

2 6 10 14 18 22 26 30 34 38 42 46

Inte

nsity

(cps

)

2120579 (deg)

Pure MMT

d001 = 118 A

d001 = 242 A

d001 = 213 A

d001 = 274 A


PEO-MMT = 03 1

Figure 3 XRD patterns of PVA-MMT mixtures in function ofmodifier ratioshost weight ratios (PVAMMT = 03 05 and 1)

32 Characterization of the PVA Modified MMT (PVA-MMTSystem) The modification of MMT layers was achieved byreaction with polyvinyl alcohol (PVA) Comparison of theintercalated gallery height with that of the pristine MMT(97 A) is shown in XRD scans in Figure 3 for 03 05 and1 PVAMMT ratiosThe basal spacing increase systematicallyfor the increasing of PVA loading from 03 (d

001= 21 A) to 1

(d001

= 27 A)This result was also reported by Strawhecker and Manias

[16] which suggests that the existence of periodic assembliesof intercalated MMT layers can lead to large clay d-spacingproportional to PVA concentration in the hybrid material Soin our case while the 50wt of PVA (ratio of 11) gave the bestresult in enhancing the layer distance this PVA concentrationwas chosen for the synthesis of further PU nanocomposites


d001 = 3582 A

d001 = 1901 Ad001 = 4030 A

d001 = 1809 A

7

5

3

1

100

90

80

70

60

50

40

30

20

10

0

05 1 2 3 4 5 6 7 8 9

2120579 (∘)

(a)

05 1 2 3 4 5 6 7 8 9 10

100

90

80

70

60

50

40

30

20

10

0

d001 = 552 A

d001 = 27 276 A

d001 = 26 27 A7

5

31

2120579 (∘)

ndash

ndash

(b)

Figure 4 XRD patterns of the PUorganoclay nanocomposites reinforced by (a) MMT modified by PEO (PEOMMT = 05) (b) MMTmodified by PVA (PVAMMT = 1)

33 PUOrganoclay Nanocomposites

331 WAXD Analysis The PEO-MMT (PEOMMT = 03)and PVA-MMT (PVAMMT = 1) organoclays were used asreinforced phases in the PU nanocomposites The XRD pat-terns of PUPEO-MMTand PUPVA-MMTnanocompositesare shown in Figure 4 In both diagrams the absence ofdetectable XRD peaks (2120579 = 2ndash10∘) in 1 and 3 filler contentPU nanocomposites might indicate the exfoliation and dis-persion of the montmorillonite layers in the PU matrix

Broad diffraction peaks are observed at 2120579 = 46∘ (d001

=19 A) and 33∘ (d

001= 27 A) for PUPEO-MMT and PUPVA-

MMT respectively at organoclay loading rate of 5 and7 A second peak showing another population of d-spacing was observed at about 35ndash40 A (PUPEO-MMT) or55 A (PUPVA-MMT) This result shows that in the caseof 5wt and 7wt loading the silicate layers in the PUnanocomposites still mostly remain in themodified structurecorresponding to the clear d

001peak at 19 A for PEO-MMT

and at 27 A for PVA-MMT In other hand another broadenpeak found at a lower 2120579 angle (35ndash40 A) in PUPEO-MMTsample and at 55 A in PUPVA-MMT sample was referredto a part of PU chain which might intercalate and expandpartially the organoclay gallery

332 TEM Analysis The direct measure of the nanometer-scale dispersion of the layered silicates in the PU matrix canbe observed in the cross-section TEMmicrographs of the PUnanocomposites Figure 5 shows the TEM images of 3 and7 PEO and PVA modified MMT in PU samples

The lattice fringe of the organoclay silicate layers (darkerline) were observed in the PU matrix At 3 filler loadingrate in the case of PEO-modified MMT (Figure 5(a)) theclay layers are nearly separated from each other with someinterlayer spacing larger than the one of raw MMT distance(close to 15 nm) While the organoclay modified by PVA are

arranged in 4ndash7 layers stacking in disorder This is evidencethat these organoclays are intercalated in PU Only very fewlayers completely separated from others are exfoliated

At a higher organoclay content for 7 of PEO andPVA modified clay (Figures 5(b) and 5(d)) the layeredfiller is arranged in intercalated periodic stacking with 15ndash2 nm almost regular d-spacing In this case the effectiveentry of PU molecules in between the organically modifiedinterlamellar spacing could not be achieved to cause anexfoliation of the silicate layers in PU

333 FTIR Analysis As reported in the literature [8 917 18] one important reason for the good dispersion ofmodified clay in the materials (at 3 wt filler) is the stronginteraction between the PU chains and clays modified byhydroxyl agents This interaction may be due to either theformation of hydrogen bond between the ndashOH groups ofintercalated polyols agent (PVA) and carbonyl groups of PUor to the bound amino group of urethane linkage attach tothe layer surface O atoms through a H bond (in the caseof PEO modified clay) The modified montmorillonites wereextracted by soxhlet in 48 h using DMF as an extractionsolvent from the PUmodified MMT nanocomposites andthey were compared to pristine modified clay for their FTIRsignals (Figure 7) in order to study the interaction of PUmatrix with the modified clay If there is a strong hydrogeninteraction between PU chains and modified clay surfacethe residual PU chains must be detected in clay surface afterextraction

The IR spectra of the extracted filler (Figure 7) illustratedthe evidence of an interaction between clay and polymerchains in the form of physically adsorbed PU chains Theband at 2980ndash2864 cmminus1 in the extracted filler and the rawmodified MMTs are attributed to the asymmetric and sym-metricC-H stretching vibrationsThebandofC=Ostretchingvibrations forms a doublet in the extracted filler spectra


(a) (b)

(c) (d)

Figure 5 TEM images of PU nanocomposites prepared from organoclay modified by (a) PEO-MMT at 3wt (b) PEO-MMT at 7wt (c)PVA-MMT at 3wt and (d) PVA-MMT at 7wt

consisting with the free C=O band at 1730 cmminus1 and thecarbonyls group vibration interacting with hydrogen bondswhich are shifted to 1720 cmminus1 especially in the case of PVAmodified clay (shown in Figure 7) This implies that thehydrogen interaction has occurred between the urethaneC=O group and OH group of PVA whose chains are attachedto surface layer through aHbond (Figure 6)This explanationis based on the study of Pattanayak and Jana [23] who hasused the FT-IR analysis to prove the hydrogen interactionbetween C=O of urethane linkage and alkylammoniumOH group and reported that if the organically modifiedmontmorillonite acted as chain extender it was observed thatthe reactive clay was completely exfoliated in polyurethanematrix The explanation from these authors [18 23 24 28]might be adequate to our situation using PVA as themodifierin which some polymer chain ends with ndashNCO groupsdiffused to the vicinity of the clay galleries during nanocom-posites preparation and might react with ndashOH group ofPVA modifier to produce urethane linkage ndashCOndashNHndash Theurethane linkages in turn formed hydrogen bonds with thesecond ndashOH group residing on the other PVA chain inside

the clay galleries as illustrated in Figure 6(b)Meanwhile thishydrogen interaction cannot happen in case of PEOmodifiedclay but only the hydrogen interaction between the ethoxygroup of PEO and amide group of urethane linkage mayoccur (Figure 6(a)) That is why the peak of hydrogen liaisonC=O stretching at 1720 cmminus1 is not observed in this case(Figure 7)

This phenomenon might bring out that these remarkablehydrogen interactions between clay surface and polymerchain would explain partly the better dispersion of clay inmatrix This result is similar to those obtained by Rehab andSalahuddin [25] or Pattanayak and Jana [18]

334 Thermal Behavior Analysis The thermal properties ofpure PU PUPEO-MMT and PUPVA-MMT nanocompos-ites were studied by DSC in the range minus100∘C to 250∘C(Figure 8) The DSC curves show that the glass transitiontemperature of PUorganoclay nanocomposites lie betweenminus28∘C andminus29∘C nearly identical to that of pure PU atminus28∘C[28ndash30] The effect of small amounts of dispersed modifiedMMT in the free volume of PUhas no significant influence on


H

H

H

H

OO

O O

O O O

OO

C CN N

Slicate layer Slicate layer Slicate layer

n

n

(a)

H

HHH

H H

C C C C C C C CCC

H

HHH

OH

OHHC

OH

OHH

H

HHH

H H

C C C C C C C

H

H H

H

C

H

HH

OH

OH OH

OHH

O O

OOO N N N

Slicate layer Slicate layer Slicate layer Slicate layer Slicate layer Slicate layer

(b)

Figure 6 Schematic representation of the hydrogen bonding by clay-tethered polyurethane chain

0

10

20

30

40

50

60

399899139918992399289933993899

Tran

smitt

ance

()

PEO-MMTPVA-MMT

Residue of PUPEO-MMT systemResidue of PUPVA-MMT system

C=O

Hydrogen linkC=Ofree

minusCH2

(cm-1)

Figure 7 Infrared spectra of the organoclay (PEO-MMT and PVA-MMT) and the residues of PUorganoclay nanocomposites

the glass transition temperature of PU In the zone of productmelting point the endothermic peak area of PUPEO-MMTand PUPVA-MMT is considered to be fairly larger thanthat of pure PU (figure not shown in the case of PUPVA-MMT) which means that organoclay did give some effect onthe morphology of thermoplastic PU nanocomposite Thisresult is adequate to that of Chen et al [21] At the contentof 3 wt PEO PVA-MMT and 5wt PVA-MMT loading(Table 1) in the nanocomposite the increase of the meltingtemperature of material and the melting peak area promotethe ordering in hard segments and the demixing of soft andhard segment [21 31] At the higher contents of clay in thenanocomposites the melting temperature of material seemsto be decreased This phenomenon is due to the aggregationof clay resulting from the mobility enhancement of the hardsegment in material

The thermal stability of PU PUPEO-MMT andPUPVA-MMT nanocomposite films was also investigatedby TGA (data in Table 2)The degradation process passed

0

minus1

minus2

minus3

minus4

minus5

minus6

minus7

minus1100

minus850

minus600

minus350

minus100

150

400

650

900

1150

1400

1650

Flux

de c

hale

ur (W

g)

PUPUPEO-MMT (1wt)

PUPEO-MMT (3wt)

PUPEO-MMT (5wt)

PUPEO-MMT (7wt)

PUPUPEO-MMT (1wt)PUPEO-MMT (3wt)

PUPEO-MMT (5wt)PUPEO-MMT (7wt)

Temperature (∘C)

Figure 8 The DSC curves of PUPEO-MMT nanocomposites as afunction of PEO-MMT filler loading content

Table 1 DSC analysis data for the PUPEO-MMT nanocompositesat different contents of PEO-MMT

Sample PEO-MMT loading( massique)

119879

119892of soft

segment (∘C)119879

119898of

material (∘C)

PUPEO-MMT

0 minus28 771 minus28 763 minus29 815 minus28 737 minus28 72

PUPVA-MMT

1 minus28 773 minus26 805 minus27 827 minus27 75


Table 2 Thermal analysis data of polyurethane nanocomposites for different loading contents of PEO-MMT

SystemPEO-MMT load( of mass) 119879ID

lowast (∘C) 119879max1lowastlowast (∘C) 119879max2

lowastlowast (∘C)Weight loss (wt)

190ndash320(∘C)

320ndash570(∘C)

PU 0 196 314 570sim78 sim214

PUPEO-MMT

1 206 329 565sim83 sim161

3 230 324 568sim801 sim172

5 251 332 565sim77 sim181

7 255 333 564sim76 sim176

PUPVA-MMT

1 210 320 568sim79 sim207

3 235 327 571sim83 148

5 254 335 566sim77 sim183

7 261 337 565sim75 sim195

lowast119879ID initial decomposition temperaturelowastlowast119879max1 and 119879max2 maximal decomposition temperature at the first and second stage respectively

through three stages as usually observed in thermoplastic PU[32] In the first and second stage (from 190∘C to 320∘C) theurethane bonds decompose to form alcohols and isocyanatesComplete volatilisation of resulting chain fragments ishindered by dimerisation of isocyanates to carbodiimidewhich react with the alcohol groups to give relatively stablesubstituted urea (second step) that decompose in the thirdstage (310∘Cndash570∘C) Trimerisation of isocyanates may alsooccur under certain conditions to yield thermally stableisocyanurate rings The final step is the high temperaturedegradation of these stabilised structures to yield volatileproducts and a small amount of carbonaceous char [32 33]

The temperatures at 10 weight loss of both series ofnanocomposite films are slightly higher than that of purePU It shows that the thermal degradation temperatureof the nanocomposites is enhanced compared to that ofneat PU The introduction of inorganic components intoorganicmaterials can enhance their thermal resistance as thedispersed silicate layers hinder the permeability of volatiledegradation products out of the material [8 21 29 33] Theincrease in thermal stability could also be attributed to thehigh thermal stability of clay and the interaction between theclay particles and the polymer matrix Similar trends havebeen reported in other papers [26 29 32] Moreover thermalstability increases with an increase in clay loading content

335 Dynamic Mechanical Analysis DMAwas used at roomtemperature to examine the viscoelastic response of thenanocomposite material to cyclic deformation namely elas-tic modulus (including storage modulus E1015840 and loss modulusE10158401015840) and loss factors (tan120575) for PUPVA-MMT and PUPEO-MMT-nanocomposites The enhancement of storage modu-lus is directly attributed to the reinforcement provided by thedispersed silicate layers [7 8 11] and storage modulus canalso be affected by the interfacial interaction between silicatelayers and polyurethane matrix Therefore storage modulusincreased with increasing the clay loading content and theirorganoclay dispersion

Table 3 Storage modulus of PU PUPEO-MMT and PUPVA-MMT nanocomposites

Sample Loading content(Weight )

Storage modulus(E1015840 MPa) tan120575 lowast 10

PU 0 312 139

PUPEO-MMT

1 399 1253 428 1105 449 1067 421 116

PUPVA-MMT

1 410 1223 485 1145 502 1097 488 112

Both systems showed a significant increase in the storagemodulus based on the amount of MMT (Table 3) In the caseof PUPVA-MMT this increase is higher than that for thePUPEO-MMT As mentioned above this might be due tobetter dispersion of clay in the PU matrix resulting in thestrong interactions between polyurethane matrix and layeredsilicates as shown in IR results [18 21 22] Numerous studiesin the literature reported the same result [1 8] The lossfactors (tan120575) of the two PUnanocomposite systems decreasecompared to PU indicating that the addition of clay diminishthe polymer chains mobility as previously reported in theliterature [8]

336 Water Absorption Measurement Properties of manymaterials change with the difference in water absorptionThe present application of PU is limited because its excellentproperties can be greatly affected by water absorption Forexample most of the mechanical properties decrease greatlywith the increase of relative humidity

In the presence of clay the water absorption ratios ofPU nanocomposites were nearly lower than that of pure PU(Table 4) This can be explained by a mechanism of water


Table 4 Water absorption of PUPEO-MMT and PUPVA-MMTsystem

Materials Absorption uptake of water (wt) after 122 hoursModified claycontent (wt) 0 1 3 5 7

PUPEO-MMT 216 182 191 209 218PUPVA-MMT 168 171 177 210

0

1

2

3

4

5

6

0 1 3 5 7

Youn

g m

odul

us (M

Pa)

PUPEO-MMTPUPEO-MMT after the water absorptionPUPVA-MMTPUPVA-MMT after water absorptionPUPU after water absorption

Clay content in PU matrix (wt)

Figure 9 Youngrsquos modulus of PU PUPEO-MMT and PUPVA-MMT nanocomposites before and after water absorption

absorption controlled by two competing factors the waterabsorption by the modified clay inside the nanocomposite(the absorption content of the nanocomposites will increasewith the organoclay content) and the mean free path of watermolecules to pass through the network of organoclayPUincreasing with the dispersion of the modified MMT in thePU matrix at a nanometer scale [21] These two competitiveeffects result in the lowestwater absorption for 1wt of organ-oclay in PU (Table 4) While the load content of organoclaybecame more than 1 the clay-water absorption becamedominant leading to slightly higher water absorption In thecase of PVAmodified clay the content of water absorbed intomaterial is fewer than that of PEO modified clay case Thisresult is due to the better dispersion of organoclay in polymermatrix

The Youngrsquos modulus of nanocomposite material is alsomeasured after the water absorption experiment By seeingin the histogram of Figures 9 and 10 both of the two casesthe loss of Youngrsquos modulus is proportional to the content ofabsorbedwater And at lower content the effect of organoclayon the loss of modulus value seems to be not importantIn addition with the presence of PVA modified clay theloss of modulus in material is lower than that using thePEO modified clay at any loading This is due to the betterdispersion of the filler modified by PVA

0

5

10

15

20

25

30

0 1 3 5 7

Los

s of Y

oung

mod

ulus

()

Clay content (wt)

PUPEO-MMTPUPVA-MMT

Figure 10 Youngrsquos modulus loss of PU PUPEO-MMT andPUPVA-MMT nanocomposites as a function of water absorptioncontent

4 Conclusion

The following conclusions are based on our observationsinvolving the modification of clay and the elaboration ofPU nanocomposite based on modified clay The purifiedVietnamese clay was successfully modified by two nonionicsurfactants PEO and PVA and the result interlayer distanceof MMT LD increases from 18 to 27 A Ester-TPUclaynanocomposites were prepared by in situ polymerizationusing two types of modified clays Morphological analysisshowed that the d-spacing clearly increased with somedisorder for low MMT content whereas for higher con-tent the reinforced phase display the intercalated structuresrearranged to a major extent The introduction of inorganiccomponents into organic materials can partially enhancetheir thermal resistance compared to that of neat PU Youngrsquosmodulus of material enhanced confirms the good dispersionof clays in PU matrix But when the addition of organoclayreached more than 1 the water absorption function of claybecame dominant leading to slightly higher water absorptionand resulted in the decrease of Youngrsquos modulus

Conflict of Interests

Holding the copyright in this work the authors of the paperwould like to declare that this research does not involve anyconflict of interests The material sources for the study wereall purchased from the commercial companies such as ClayMinerals Depository Hiep Phu Company and Sigma-AlrichCompany Company

Acknowledgments

The authors are grateful to the National University of Ho ChiMinh City Vietnam for the financial support and LCME labof University of Savoie France for the support of materialcharacterizations


References

[1] Z Wang and T J Pinnavaia ldquoNanolayer reinforcement ofelastomeric polyurethanerdquo Chemistry of Materials vol 10 no12 pp 3769ndash3771 1998

[2] S Solarski S Benali M Rochery et al ldquoSynthesis of a pol-yurethaneclay nanocomposite used as coating interactionsbetween the counterions of clay and the isocyanate and inci-dence on the nanocomposite structurerdquo Journal of AppliedPolymer Science vol 95 no 2 pp 238ndash244 2005

[3] G W Beall and S J Tsipursky ldquoNanocomposites producedutilizing a novel ion-dipole clay surfacemodificationrdquo inChem-istry and Technology of Polymer Additives S Al-Malaika AGolovoy andCAWilkie Eds pp 266ndash280 Blackwell ScienceOxford UK 1999

[4] P F Luckham and S Rossi ldquoColloidal and rheological proper-ties of bentonite suspensionsrdquoAdvances in Colloid and InterfaceScience vol 82 no 1 pp 43ndash92 1999

[5] H Sato ldquoEffects of the orientation of smectite particles and ionicstrength on diffusion and activation enthalpies of Iminus and Cs+ions in compacted smectiterdquo Applied Clay Science vol 29 no3-4 pp 267ndash281 2005

[6] A Pacuła E Bielanska A Gaweł K Bahranowski and EM Serwicka ldquoTextural effects in powdered montmorillon-ite induced by freeze-drying and ultrasound pretreatmentrdquoApplied Clay Science vol 32 no 1-2 pp 64ndash72 2006

[7] M Alexandre and P Dubois ldquoPolymer-layered silicate nano-composites preparation properties and uses of a new class ofmaterialsrdquo Materials Science and Engineering R vol 28 no 1pp 1ndash63 2000

[8] J Xiong Z Zheng H Jiang S Ye and X Wang ldquoReinforce-ment of polyurethane composites with an organically modifiedmontmorilloniterdquo Composites A vol 38 no 1 pp 132ndash137 2007

[9] Q M Jia M Zheng H X Chen and R J Shen ldquoSynthesisand characterization of polyurethaneepoxy interpenetratingnetwork nanocomposites with organoclaysrdquo Polymer Bulletinvol 54 no 1-2 pp 65ndash73 2005

[10] S Sinha Ray and M Okamoto ldquoPolymerlayered silicate nano-composites a review from preparation to processingrdquo Progressin Polymer Science vol 28 no 11 pp 1539ndash1641 2003

[11] P C Lebaron Z Wang and T J Pinnavaia ldquoPolymer-layeredsilicate nanocomposites an overviewrdquoApplied Clay Science vol15 no 1-2 pp 11ndash29 1999

[12] Z Shen G P Simon and Y-B Cheng ldquoSaturation ratio ofpoly(ethylene oxide) to silicate in melt intercalated nanocom-positesrdquo European Polymer Journal vol 39 no 9 pp 1917ndash19242003

[13] Z Shen G P Simon and Y-B Cheng ldquoComparison ofsolution intercalation and melt intercalation of polymer-claynanocompositesrdquo Polymer vol 43 no 15 pp 4251ndash4260 2002

[14] R A Vaia B B Sauer O K Tse and E P Giannelis ldquoRelax-ations of confined chains in polymer nanocomposites glasstransition properties of poly(ethylene oxide) intercalated inmontmorilloniterdquo Journal of Polymer Science B vol 35 no 1pp 59ndash67 1997

[15] P Aranda and E Ruiz-Hitzky ldquoPoly(ethylene oxide)-silicateintercalationmaterialsrdquo Chemistry of Materials vol 4 no 6 pp1395ndash1403 1992

[16] K E Strawhecker and E Manias ldquoStructure and propertiesof poly(vinyl alcohol)Na+ montmorillonite nanocompositesrdquoChemistry of Materials vol 12 no 10 pp 2943ndash2949 2000

[17] L Pizzatto A Lizot R Fiorio et al ldquoSynthesis and charac-terization of thermoplastic polyurethanenanoclay compositesrdquoMaterials Science and Engineering C vol 29 no 2 pp 474ndash4782009

[18] A Pattanayak and S C Jana ldquoSynthesis of thermoplasticpolyurethane nanocomposites of reactive nanoclay by bulkpolymerization methodsrdquo Polymer vol 46 no 10 pp 3275ndash3288 2005

[19] C Zilg RThomann R Mulhaupt and J Finter ldquoPolyurethanenanocomposites containing laminated anisotropic nanopar-ticles derived from organophilic layered silicatesrdquo AdvancedMaterials vol 11 no 1 pp 49ndash52 1999

[20] A Cheng S Wu D Jiang F Wu and J Shen ldquoStudy of elas-tomeric polyurethane nanocomposites prepared from graftedorganic-montmorilloniterdquo Colloid and Polymer Science vol284 no 9 pp 1057ndash1061 2005

[21] T K Chen Y I Tien and K HWei ldquoSynthesis and characteri-zation of novel segmented polyurethane clay nanocomposite viapoly(epsilon-caprolactone)clayrdquo Journal of Polymer Science Avol 37 pp 2225ndash2233 1999

[22] Y I Tien and K H Wei ldquoHigh-tensile-property layered sili-catespolyurethane nanocomposites by using reactive silicatesas pseudo chain extendersrdquoMacromolecules vol 34 no 26 pp9045ndash9052 2001

[23] A Pattanayak and S C Jana ldquoThermoplastic polyurethanenanocomposites of reactive silicate clays effects of soft segmentson propertiesrdquo Polymer vol 46 no 14 pp 5183ndash5193 2005

[24] A Pattanayak and S C Jana ldquoHigh-strength and low-stiffnesscomposites of nanoclay-filled thermoplastic polyurethanesrdquoPolymer Engineering and Science vol 45 no 11 pp 1532ndash15392005

[25] A Rehab and N Salahuddin ldquoNanocomposite materials basedon polyurethane intercalated into montmorillonite clayrdquoMate-rials Science and Engineering A vol 399 no 1-2 pp 368ndash3762005

[26] C-N H Thuc A-C Grillet L Reinert F Ohashi H H Thucand L Duclaux ldquoSeparation and purification of montmoril-lonite and polyethylene oxide modified montmorillonite fromVietnamese bentonitesrdquo Applied Clay Science vol 49 no 3 pp229ndash238 2010

[27] C N H Thuc Purification intercalationexfoliation of naturalmontmorillonite for elaboration of PU nanocomposite [PhDthesis] University of Savoie 2008

[28] I Clemitson Castable Polyurethane Elastomers CRC amp Tayloramp Francis Boca Raton Fla USA 2008

[29] J-H Chang and Y U An ldquoNanocomposites of polyurethanewith various organoclays thermomechanical properties mor-phology and gas permeabilityrdquo Journal of Polymer Science B vol40 no 7 pp 670ndash677 2002

[30] C Jung Synthesis of Thermoplastic Polyurethane and Polyur-ethane Nanocomposites under Chaotic Mixing Conditions TheGraduate Faculty of the University of Akron 2005

[31] C H Dan M H Lee Y D Kim B H Min and J H KimldquoEffect of clay modifiers on the morphology and physical prop-erties of thermoplastic polyurethaneclay nanocompositesrdquoPolymer vol 47 no 19 pp 6718ndash6730 2006


[32] M Berta C Lindsay G Pans and G Camino ldquoEffect ofchemical structure on combustion and thermal behaviourof polyurethane elastomer layered silicate nanocompositesrdquoPolymer Degradation and Stability vol 91 no 5 pp 1179ndash11912006

[33] W J Choi S H Kim Y Jin Kim and S C Kim ldquoSynthesis ofchain-extended organifier and properties of polyurethaneclaynanocompositesrdquo Polymer vol 45 no 17 pp 6045ndash6057 2004

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Polymer ScienceInternational Journal of


CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of


thinspInternationalthinspJournalthinspof

BiomaterialsHindawithinspPublishingthinspCorporationhttpwwwhindawicom Volumethinsp2014


NaNoscieNceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

CrystallographyJournal of

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of

BioMed Research International



Volume 2014

MaterialsJournal of

Nano

materials


Journal ofNanomaterials


lowering the surface energy improving the wetting charac-teristics of the polymer matrix and enlarging the interlayerspacing of clay The normally hydrophilic silicate surfaceshould be converted to an organophilic one allowing theintercalation of many engineering polymers After Xiong etal [8] there are two main factors that should be consideredin forming polymerclay nanocomposites firstly the organicmodifier molecules must enter in interlayer galleries inenlarging the interlayer space of MMT and then result theeasier interaction of polymer molecules or monomers andclay layers Generally the modification is processed by ion-exchange reactions with cationic surfactants including pri-mary secondary tertiary and quaternary alkylammonium oralkylphosphonium cations [7 9ndash11] or by intercalation in clayof hydrophilic polymers such as polyethylene oxide (PEO)or polyvinyl alcohol (PVA) [10 12ndash16]

Many researchers studied the PU nanocomposites toimprove the mechanical performance of polyurethane andreduce the production cost [7 10 11]However such approachhas some disadvantages such as the reduction of ductilityand the decrease of water resistance There are very fewreports on TPU composites and nanocomposites preparedby bulk and melt processing [17 18] Recently much efforthas been conducted to find new methods for preparingPUmodifiedMMTWang and Pinnavaia [1] or Zilg et al [19]reported an intercalated PUMMT by in situ polymerizationof Toluene diisocyanate (TDI) and a mixture of polyoland MMT Cheng et al [20] proposed an intercalationmethod in solution as PU prepolymer was inserted intothe MMT intergallery in solution conditions followed by acuring procedure with 14-butanediol To further improve theproperties of PUclay nanocomposites alternate functionalmodifiers which can react with polymer are being used toprepare polymerclay nanocomposites For example in thestudy of Chen et al [21] the authors found exfoliation ofclay layers in PU nanocomposites when clay was treatedby aminolauric acid (12COOH) and benzidine (BZD) sep-arately as shown by X-Ray diffraction patterns and TEMThe mechanical property of polyurethane nanocompositewith benzidine modified clay showed much better than thatof 12-aminolauric acid treated clay and it was explainedby the difference in the interaction between the swellingagent and polyurethane molecular chain 12-Aminolauricacid contained only one terminal ndashNH

2group which might

react with aminute amount of unreacted ndashNCO to formureawhile both of the two terminal ndashNH

2groups in benzidine

could participate in the reaction Therefore cross-linkingstructure can be formed by benzidine and linear chains by12-aminolauric In another study of Tien and Wei [22] theeffect of exfoliation behavior on mechanical properties intethereduntethered PU nanocomposites was investigated byusing 1 2 and 3 hydroxyl groups in the molecules of organictreatment of layered silicates which acted as pseudochainextenders for polyurethane prepolymer X-Ray analysis ofpolyurethane nanocomposites prepared by solution methodconfirmed that with the increase of numbers of hydroxylgroups in quaternary ammonium ions the dispersion oflayered silicates in polyurethanes transformed from an inter-calated to an exfoliated state Later Pattanayak and Jana

[18 23 24] have studied the in situ reaction of polyurethanenanocomposites with reactive Cloisite 30B through bulkpolymerization Clay-polymer tethering reaction occurredunder conditions of high shear stress by using a conventionalbatch mixer Two processing methods were used in thissynthesis of nanocompositematerials In the firstmethod thechain extender 14-butanediol was added after the additionof clay in the second method the chain extension reactionwas carried out before the addition of clay Unlike the solutionpolymerization method conducted by Tien andWei [22] theaddition of clay before chain extension reaction led to poordispersion of clay particles With the confirmation of FTIRand rheological data the clay exfoliation was found to beinfluenced mainly by strong interaction between modifiedclay and PU chain

Based on the report of these authors about the clay-tethered polyurethane nanocomposites [18 21 22 25] in thepresent study we describe the preparation PUclay nanocom-posites from purified Vietnamese montmorillonite which ismodified via solution method by polyethylene oxide (PEO)and polyvinyl alcohol (PVA) molecules The modifier agentshaving the hydroxyl functional groups are considered to reactwith PU chains as pseudochain extenders for polyurethaneprepolymer Thermoplastic polyurethane nanocompositecomposed of 1 3 5 and 7wt of organoclays were then pre-pared via in situ polymerization from crystalline polypropy-lene glycol (PPG) polyols and 441015840-diphenylmethane diiso-cyanate (14-MDI) using 14-butanediol (14-BD) as chainextenderThis paper describes also themorphology and somebasic properties of the prepared PU nanocomposite

2 Experimental

21 Materials and Chemicals Vietnamese montmorillonite(MMT) minerals (LamDong Mg2+-montmorillonite) wasobtained by purification of bentonite from the Clay MineralsDepository Hiep Phu at the LamDong province (southof Vietnam) using the purification process reported inour previous study [26] The polymers used in this workfor the modification of clay were polyethylene oxide PEO(M119899= 10 000) and polyvinyl alcohol PVA (M

119899= 8700)

from Aldrich Chemical Company Inc For the synthesis ofPU 441015840-diphenylmethane diisocyanate (14-MDI Aldrich)14-butanediol (14-BD Aldrich) and polypropylene glycol(PPG M

119899= 1200 Aldrich) were used as received from

Aldrich Chemical Company The PPG 14-BD and 14-MDIreagents were vacuum dried at 80∘C for 24 h prior to use

22 Preparation of PEO and PVA Modified MMT The clayused was the purified MMT obtained from our previouspurification procedure [26] In the literature two processesare reported for the PEO or PVA intercalation of clay [1213 15] solution intercalation and melt intercalation In thiswork the solution intercalation was performed because itallows intercalating polymers with little or no polarity intolayered structure and facilitates the production of oriented-clay intercalated layer [7 27]

In a typical experiment the selected polymer and silicatewere weighed according to the designated ratio A weighed



















4solution





001






001


02000400060008000

1000012000140001600018000

2 6 10 14 18 22 26 30 34 38 42 46

Inte

nsity

(cps

)

Pure MMT

2120579 (deg)

d001 = 18 Ad001 = 182 Ad001 = 118 Ad001 = 145 A


PEO-MMT = 01 1




(sim10∘) d003

(sim151∘) and d004





0

15 25 35 45 55 65 75 85 95 105

115

125

135

145

155

165

175

185

195

Hea

t flow

(mW

)

minus30

minus25

minus20

minus15

minus10

minus5


PEO-MMT (05 1)PEO


0

1000

2000

3000

4000

5000

6000

7000

2 6 10 14 18 22 26 30 34 38 42 46

Inte

nsity

(cps

)

2120579 (deg)

Pure MMT

d001 = 118 A

d001 = 242 A

d001 = 213 A

d001 = 274 A


PEO-MMT = 03 1



001= 21 A) to 1

(d001




d001 = 3582 A

d001 = 1901 Ad001 = 4030 A

d001 = 1809 A

7

5

3

1

100

90

80

70

60

50

40

30

20

10

0

05 1 2 3 4 5 6 7 8 9

2120579 (∘)

(a)

05 1 2 3 4 5 6 7 8 9 10

100

90

80

70

60

50

40

30

20

10

0

d001 = 552 A

d001 = 27 276 A

d001 = 26 27 A7

5

31

2120579 (∘)

ndash

ndash

(b)





=19 A) and 33∘ (d












(a) (b)

(c) (d)







H

H

H

H

OO

O O

O O O

OO

C CN N


n

n

(a)

H

HHH

H H

C C C C C C C CCC

H

HHH

OH

OHHC

OH

OHH

H

HHH

H H

C C C C C C C

H

H H

H

C

H

HH

OH

OH OH

OHH

O O

OOO N N N


(b)


0

10

20

30

40

50

60

399899139918992399289933993899

Tran

smitt

ance

()

PEO-MMTPVA-MMT


C=O


minusCH2

(cm-1)




0

minus1

minus2

minus3

minus4

minus5

minus6

minus7

minus1100

minus850

minus600

minus350

minus100

150

400

650

900

1150

1400

1650

Flux

de c

hale

ur (W

g)

PUPUPEO-MMT (1wt)

PUPEO-MMT (3wt)

PUPEO-MMT (5wt)

PUPEO-MMT (7wt)



Temperature (∘C)




119879

119892of soft


119898of

material (∘C)

PUPEO-MMT


PUPVA-MMT







190ndash320(∘C)

320ndash570(∘C)

PU 0 196 314 570sim78 sim214

PUPEO-MMT

1 206 329 565sim83 sim161

3 230 324 568sim801 sim172

5 251 332 565sim77 sim181

7 255 333 564sim76 sim176

PUPVA-MMT

1 210 320 568sim79 sim207

3 235 327 571sim83 148

5 254 335 566sim77 sim183

7 261 337 565sim75 sim195








PU 0 312 139

PUPEO-MMT

1 399 1253 428 1105 449 1067 421 116

PUPVA-MMT

1 410 1223 485 1145 502 1097 488 112








0

1

2

3

4

5

6

0 1 3 5 7

Youn

g m

odul

us (M

Pa)






0

5

10

15

20

25

30

0 1 3 5 7

Los

s of Y

oung

mod

ulus

()

Clay content (wt)

PUPEO-MMTPUPVA-MMT


4 Conclusion




Acknowledgments



References










































CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials





















4solution





001






001


02000400060008000

1000012000140001600018000

2 6 10 14 18 22 26 30 34 38 42 46

Inte

nsity

(cps

)

Pure MMT

2120579 (deg)

d001 = 18 Ad001 = 182 Ad001 = 118 Ad001 = 145 A


PEO-MMT = 01 1




(sim10∘) d003

(sim151∘) and d004





0

15 25 35 45 55 65 75 85 95 105

115

125

135

145

155

165

175

185

195

Hea

t flow

(mW

)

minus30

minus25

minus20

minus15

minus10

minus5


PEO-MMT (05 1)PEO


0

1000

2000

3000

4000

5000

6000

7000

2 6 10 14 18 22 26 30 34 38 42 46

Inte

nsity

(cps

)

2120579 (deg)

Pure MMT

d001 = 118 A

d001 = 242 A

d001 = 213 A

d001 = 274 A


PEO-MMT = 03 1



001= 21 A) to 1

(d001




d001 = 3582 A

d001 = 1901 Ad001 = 4030 A

d001 = 1809 A

7

5

3

1

100

90

80

70

60

50

40

30

20

10

0

05 1 2 3 4 5 6 7 8 9

2120579 (∘)

(a)

05 1 2 3 4 5 6 7 8 9 10

100

90

80

70

60

50

40

30

20

10

0

d001 = 552 A

d001 = 27 276 A

d001 = 26 27 A7

5

31

2120579 (∘)

ndash

ndash

(b)





=19 A) and 33∘ (d












(a) (b)

(c) (d)







H

H

H

H

OO

O O

O O O

OO

C CN N


n

n

(a)

H

HHH

H H

C C C C C C C CCC

H

HHH

OH

OHHC

OH

OHH

H

HHH

H H

C C C C C C C

H

H H

H

C

H

HH

OH

OH OH

OHH

O O

OOO N N N


(b)


0

10

20

30

40

50

60

399899139918992399289933993899

Tran

smitt

ance

()

PEO-MMTPVA-MMT


C=O


minusCH2

(cm-1)




0

minus1

minus2

minus3

minus4

minus5

minus6

minus7

minus1100

minus850

minus600

minus350

minus100

150

400

650

900

1150

1400

1650

Flux

de c

hale

ur (W

g)

PUPUPEO-MMT (1wt)

PUPEO-MMT (3wt)

PUPEO-MMT (5wt)

PUPEO-MMT (7wt)



Temperature (∘C)




119879

119892of soft


119898of

material (∘C)

PUPEO-MMT


PUPVA-MMT







190ndash320(∘C)

320ndash570(∘C)

PU 0 196 314 570sim78 sim214

PUPEO-MMT

1 206 329 565sim83 sim161

3 230 324 568sim801 sim172

5 251 332 565sim77 sim181

7 255 333 564sim76 sim176

PUPVA-MMT

1 210 320 568sim79 sim207

3 235 327 571sim83 148

5 254 335 566sim77 sim183

7 261 337 565sim75 sim195








PU 0 312 139

PUPEO-MMT

1 399 1253 428 1105 449 1067 421 116

PUPVA-MMT

1 410 1223 485 1145 502 1097 488 112








0

1

2

3

4

5

6

0 1 3 5 7

Youn

g m

odul

us (M

Pa)






0

5

10

15

20

25

30

0 1 3 5 7

Los

s of Y

oung

mod

ulus

()

Clay content (wt)

PUPEO-MMTPUPVA-MMT


4 Conclusion




Acknowledgments



References










































CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials




02000400060008000

1000012000140001600018000

2 6 10 14 18 22 26 30 34 38 42 46

Inte

nsity

(cps

)

Pure MMT

2120579 (deg)

d001 = 18 Ad001 = 182 Ad001 = 118 Ad001 = 145 A


PEO-MMT = 01 1




(sim10∘) d003

(sim151∘) and d004





0

15 25 35 45 55 65 75 85 95 105

115

125

135

145

155

165

175

185

195

Hea

t flow

(mW

)

minus30

minus25

minus20

minus15

minus10

minus5


PEO-MMT (05 1)PEO


0

1000

2000

3000

4000

5000

6000

7000

2 6 10 14 18 22 26 30 34 38 42 46

Inte

nsity

(cps

)

2120579 (deg)

Pure MMT

d001 = 118 A

d001 = 242 A

d001 = 213 A

d001 = 274 A


PEO-MMT = 03 1



001= 21 A) to 1

(d001




d001 = 3582 A

d001 = 1901 Ad001 = 4030 A

d001 = 1809 A

7

5

3

1

100

90

80

70

60

50

40

30

20

10

0

05 1 2 3 4 5 6 7 8 9

2120579 (∘)

(a)

05 1 2 3 4 5 6 7 8 9 10

100

90

80

70

60

50

40

30

20

10

0

d001 = 552 A

d001 = 27 276 A

d001 = 26 27 A7

5

31

2120579 (∘)

ndash

ndash

(b)





=19 A) and 33∘ (d












(a) (b)

(c) (d)







H

H

H

H

OO

O O

O O O

OO

C CN N


n

n

(a)

H

HHH

H H

C C C C C C C CCC

H

HHH

OH

OHHC

OH

OHH

H

HHH

H H

C C C C C C C

H

H H

H

C

H

HH

OH

OH OH

OHH

O O

OOO N N N


(b)


0

10

20

30

40

50

60

399899139918992399289933993899

Tran

smitt

ance

()

PEO-MMTPVA-MMT


C=O


minusCH2

(cm-1)




0

minus1

minus2

minus3

minus4

minus5

minus6

minus7

minus1100

minus850

minus600

minus350

minus100

150

400

650

900

1150

1400

1650

Flux

de c

hale

ur (W

g)

PUPUPEO-MMT (1wt)

PUPEO-MMT (3wt)

PUPEO-MMT (5wt)

PUPEO-MMT (7wt)



Temperature (∘C)




119879

119892of soft


119898of

material (∘C)

PUPEO-MMT


PUPVA-MMT







190ndash320(∘C)

320ndash570(∘C)

PU 0 196 314 570sim78 sim214

PUPEO-MMT

1 206 329 565sim83 sim161

3 230 324 568sim801 sim172

5 251 332 565sim77 sim181

7 255 333 564sim76 sim176

PUPVA-MMT

1 210 320 568sim79 sim207

3 235 327 571sim83 148

5 254 335 566sim77 sim183

7 261 337 565sim75 sim195








PU 0 312 139

PUPEO-MMT

1 399 1253 428 1105 449 1067 421 116

PUPVA-MMT

1 410 1223 485 1145 502 1097 488 112








0

1

2

3

4

5

6

0 1 3 5 7

Youn

g m

odul

us (M

Pa)






0

5

10

15

20

25

30

0 1 3 5 7

Los

s of Y

oung

mod

ulus

()

Clay content (wt)

PUPEO-MMTPUPVA-MMT


4 Conclusion




Acknowledgments



References










































CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials




d001 = 3582 A

d001 = 1901 Ad001 = 4030 A

d001 = 1809 A

7

5

3

1

100

90

80

70

60

50

40

30

20

10

0

05 1 2 3 4 5 6 7 8 9

2120579 (∘)

(a)

05 1 2 3 4 5 6 7 8 9 10

100

90

80

70

60

50

40

30

20

10

0

d001 = 552 A

d001 = 27 276 A

d001 = 26 27 A7

5

31

2120579 (∘)

ndash

ndash

(b)





=19 A) and 33∘ (d












(a) (b)

(c) (d)







H

H

H

H

OO

O O

O O O

OO

C CN N


n

n

(a)

H

HHH

H H

C C C C C C C CCC

H

HHH

OH

OHHC

OH

OHH

H

HHH

H H

C C C C C C C

H

H H

H

C

H

HH

OH

OH OH

OHH

O O

OOO N N N


(b)


0

10

20

30

40

50

60

399899139918992399289933993899

Tran

smitt

ance

()

PEO-MMTPVA-MMT


C=O


minusCH2

(cm-1)




0

minus1

minus2

minus3

minus4

minus5

minus6

minus7

minus1100

minus850

minus600

minus350

minus100

150

400

650

900

1150

1400

1650

Flux

de c

hale

ur (W

g)

PUPUPEO-MMT (1wt)

PUPEO-MMT (3wt)

PUPEO-MMT (5wt)

PUPEO-MMT (7wt)



Temperature (∘C)




119879

119892of soft


119898of

material (∘C)

PUPEO-MMT


PUPVA-MMT







190ndash320(∘C)

320ndash570(∘C)

PU 0 196 314 570sim78 sim214

PUPEO-MMT

1 206 329 565sim83 sim161

3 230 324 568sim801 sim172

5 251 332 565sim77 sim181

7 255 333 564sim76 sim176

PUPVA-MMT

1 210 320 568sim79 sim207

3 235 327 571sim83 148

5 254 335 566sim77 sim183

7 261 337 565sim75 sim195








PU 0 312 139

PUPEO-MMT

1 399 1253 428 1105 449 1067 421 116

PUPVA-MMT

1 410 1223 485 1145 502 1097 488 112








0

1

2

3

4

5

6

0 1 3 5 7

Youn

g m

odul

us (M

Pa)






0

5

10

15

20

25

30

0 1 3 5 7

Los

s of Y

oung

mod

ulus

()

Clay content (wt)

PUPEO-MMTPUPVA-MMT


4 Conclusion




Acknowledgments



References










































CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials




(a) (b)

(c) (d)







H

H

H

H

OO

O O

O O O

OO

C CN N


n

n

(a)

H

HHH

H H

C C C C C C C CCC

H

HHH

OH

OHHC

OH

OHH

H

HHH

H H

C C C C C C C

H

H H

H

C

H

HH

OH

OH OH

OHH

O O

OOO N N N


(b)


0

10

20

30

40

50

60

399899139918992399289933993899

Tran

smitt

ance

()

PEO-MMTPVA-MMT


C=O


minusCH2

(cm-1)




0

minus1

minus2

minus3

minus4

minus5

minus6

minus7

minus1100

minus850

minus600

minus350

minus100

150

400

650

900

1150

1400

1650

Flux

de c

hale

ur (W

g)

PUPUPEO-MMT (1wt)

PUPEO-MMT (3wt)

PUPEO-MMT (5wt)

PUPEO-MMT (7wt)



Temperature (∘C)




119879

119892of soft


119898of

material (∘C)

PUPEO-MMT


PUPVA-MMT







190ndash320(∘C)

320ndash570(∘C)

PU 0 196 314 570sim78 sim214

PUPEO-MMT

1 206 329 565sim83 sim161

3 230 324 568sim801 sim172

5 251 332 565sim77 sim181

7 255 333 564sim76 sim176

PUPVA-MMT

1 210 320 568sim79 sim207

3 235 327 571sim83 148

5 254 335 566sim77 sim183

7 261 337 565sim75 sim195








PU 0 312 139

PUPEO-MMT

1 399 1253 428 1105 449 1067 421 116

PUPVA-MMT

1 410 1223 485 1145 502 1097 488 112








0

1

2

3

4

5

6

0 1 3 5 7

Youn

g m

odul

us (M

Pa)






0

5

10

15

20

25

30

0 1 3 5 7

Los

s of Y

oung

mod

ulus

()

Clay content (wt)

PUPEO-MMTPUPVA-MMT


4 Conclusion




Acknowledgments



References










































CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials




H

H

H

H

OO

O O

O O O

OO

C CN N


n

n

(a)

H

HHH

H H

C C C C C C C CCC

H

HHH

OH

OHHC

OH

OHH

H

HHH

H H

C C C C C C C

H

H H

H

C

H

HH

OH

OH OH

OHH

O O

OOO N N N


(b)


0

10

20

30

40

50

60

399899139918992399289933993899

Tran

smitt

ance

()

PEO-MMTPVA-MMT


C=O


minusCH2

(cm-1)




0

minus1

minus2

minus3

minus4

minus5

minus6

minus7

minus1100

minus850

minus600

minus350

minus100

150

400

650

900

1150

1400

1650

Flux

de c

hale

ur (W

g)

PUPUPEO-MMT (1wt)

PUPEO-MMT (3wt)

PUPEO-MMT (5wt)

PUPEO-MMT (7wt)



Temperature (∘C)




119879

119892of soft


119898of

material (∘C)

PUPEO-MMT


PUPVA-MMT







190ndash320(∘C)

320ndash570(∘C)

PU 0 196 314 570sim78 sim214

PUPEO-MMT

1 206 329 565sim83 sim161

3 230 324 568sim801 sim172

5 251 332 565sim77 sim181

7 255 333 564sim76 sim176

PUPVA-MMT

1 210 320 568sim79 sim207

3 235 327 571sim83 148

5 254 335 566sim77 sim183

7 261 337 565sim75 sim195








PU 0 312 139

PUPEO-MMT

1 399 1253 428 1105 449 1067 421 116

PUPVA-MMT

1 410 1223 485 1145 502 1097 488 112








0

1

2

3

4

5

6

0 1 3 5 7

Youn

g m

odul

us (M

Pa)






0

5

10

15

20

25

30

0 1 3 5 7

Los

s of Y

oung

mod

ulus

()

Clay content (wt)

PUPEO-MMTPUPVA-MMT


4 Conclusion




Acknowledgments



References










































CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials








190ndash320(∘C)

320ndash570(∘C)

PU 0 196 314 570sim78 sim214

PUPEO-MMT

1 206 329 565sim83 sim161

3 230 324 568sim801 sim172

5 251 332 565sim77 sim181

7 255 333 564sim76 sim176

PUPVA-MMT

1 210 320 568sim79 sim207

3 235 327 571sim83 148

5 254 335 566sim77 sim183

7 261 337 565sim75 sim195








PU 0 312 139

PUPEO-MMT

1 399 1253 428 1105 449 1067 421 116

PUPVA-MMT

1 410 1223 485 1145 502 1097 488 112








0

1

2

3

4

5

6

0 1 3 5 7

Youn

g m

odul

us (M

Pa)






0

5

10

15

20

25

30

0 1 3 5 7

Los

s of Y

oung

mod

ulus

()

Clay content (wt)

PUPEO-MMTPUPVA-MMT


4 Conclusion




Acknowledgments



References










































CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials







0

1

2

3

4

5

6

0 1 3 5 7

Youn

g m

odul

us (M

Pa)






0

5

10

15

20

25

30

0 1 3 5 7

Los

s of Y

oung

mod

ulus

()

Clay content (wt)

PUPEO-MMTPUPVA-MMT


4 Conclusion




Acknowledgments



References










































CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials




References










































CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials













CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials



Preparation and Characterization of Polyurethane Nanocomposites Using Vietnamese Montmorillonite...

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Transcript of Preparation and Characterization of Polyurethane Nanocomposites Using Vietnamese Montmorillonite...