Geckeler K.E., Nishide H. (Eds.) Advanced Nanomaterials

13.4 Poly(Lactide) (PLA)-Based Nanocomposites 445

ably enhanced by compatibilization, due to the combined interactions of the

organoclay surfactant with the PLA chains and the MAH groups of the compati-

bilizer. In the 10 wt% - nanocomposite, mixed (i.e., intercalated and exfoliated)

nanostructures were detected due to the high concentration of the ﬁ ller. Both, the

rheological and mechanical properties suggested that a type of silicate network

had been formed.

Sinha Ray et al . [151] noted that, although high - molecular - weight PCL was

immiscible with PLA, oligomeric PCL was highly miscible (as indicated by a shift

in T

g

). Consequently, the group used such an α , ω - hydroxy - terminated oligomeric

PCL (0.2 – 3 wt%) as compatibilizer when preparing PLA/octadecylammonium -

modiﬁ ed MMT nanocomposites. The incorporation of a compatibilizer into the

system led to a better parallel stacking of the silicate layers, and also to a much

stronger ﬂ occulation as a result of the hydroxylated edge – edge interaction of the

silicate layers. Owing to interaction between the clay particles and the PLA matrix

with oligomeric PCL, the disk – disk interaction was considered to play an impor-

tant role in determining the stability of the clay particles, and hence any enhance-

ment of the mechanical properties of such nanocomposites. These systems, which

were the ﬁ rst successful intercalated - type PLA/layered silicate nanocomposites,

exhibited remarkable improvements in the materials properties of both solid and

melt states when compared to the matrix without clay.

Shortly thereafter, Kubies et al . [152] prepared PCL - layered silicate nanocompos-

ite masterbatches by the ROP of ε - CL in the presence of the OMMT, Cloisite 30B.

The masterbatch MB30 (28 wt% MMT, PCL with M

w

= 1800) had an intercalated

structure, while MB8 (7.5 wt% MMT, PCL with M

w

= 7500) was exfoliated. Subse-

quently, high - molecular - weight PLLA nanocomposites containing 0.5 – 2.5 wt%

MMT were obtained by the melt - blending of PLLA (M

w

= 4.5 × 1 0

5

Da) with PCL

masterbatches or Cloisite 30B. The MMT particles in PLLA/Cloisite 30B and

PLLA/MB30 nanocomposites were intercalated. In contrast to expectation, the

exfoliated silicate layers of MB8 were not transferred into the PLLA matrix of the

PLLA/MB8 nanocomposites. Due to a low miscibility of PCL and PLLA, MMT

remained in the phase - separated masterbatch domains. The stress – strain charac-

teristics of PLLA nanocomposites (i.e., Young ’ s modulus), yield stress and yield

strain, were decreased with increasing MMT concentration, associated with an

increase in the PCL content (up to 35.4 wt% in PLLA/MB8). The expected stiffen-

ing effect of the MMT was low, due to a low aspect ratio of its particles, and was

obscured by both the plastifying effect of PCL and the low PLLA crystallinity.

Interestingly, in contrast to the neat PLLA, ductility was enhanced in all PLLA/

Cloisite 30B materials, and also in the PLLA/masterbatch nanocomposites with

low MMT concentrations.

As reported Sinha Ray et al . [151] , the miscibility of PCL with the PLA matrix

plays a crucial role in its possible use as a compatibilizer. However, Yu et al . [153]

more recently prepared PLA/PCL 90/10 blends containing different amounts

(1 – 10 wt%) of organophilic MMTs modiﬁ ed with bis - (2 - hydroxyethyl) - methyl -

(hydrogenated tallow alkyl) ammonium cations, by using a counter - rotating, dis-

continuous mixer. The silicate layers of the clay were intercalated and distributed

446 13 Nanocomposites Based on Phyllosilicates

randomly in the matrix. The addition of organophilic MMT to the PLLA/PCL blend

led to a signiﬁ cant improvement in the tensile properties and dynamic mechanical

properties of the nanocomposites. In contrast, the layered silicate caused a clear

improvement in the thermal stability of the PLLA/PCL blends when the organo-

philic MMT content was less than 5 wt%. SEM images conﬁ rmed that the addition

of OMMT could reduce the size of the phase - separated particles, causing the mate-

rial to become more uniform.

Interestingly, it has been suggested that OMMT might play the role of a com-

patibilizer, and a similar reduction in particle size in phase - separated blends was

reported for a triblock PLA - PCL - PLA copolymer used as a compatibilizer in similar

blend systems [154] . These authors ascribed this phenomenon to the intercalation

of polymer molecules in OMMT, which increases the viscosity ratio and results in

the retardation of coalescence of the dispersed phase - separated particles and an

enhanced compatibility as a result of the intercalation of both PLLA and PCL

molecules into the same OMMT gallery.

Hence, the possible use of a second polymeric phase as a compatibilizer should

focus on the miscibility or compatibility between the two polymeric phases, in

order to predict the morphology, as this depends not only on the level of dispersion

of the lamellae in the polymeric matrix, but also on the phase distribution, which

in turn inﬂ uences the preferential distribution and orientation of the lamellae.

Recently, much interest has been expressed regarding not only the plasticization

of PLA [130, 155, 156] , but also the possible addition of a plasticizer to PLA/layered

silicate nanocomposites. This subject is particularly attractive because it might

allow a balance to be achieved between the mechanical and gas - barrier properties,

since plasticization will in general provide an improved ductility but reduce the

gas - barrier effects. In contrast, adding a nanoﬁ ller would improve the stiffness

and gas - barrier properties of the PLA. Hence, the plasticization of PLA nanocom-

posites might provide a more ductile material, without either decreasing and/

or improving its gas - barrier properties. Plasticized PLA - based nanocomposites

were prepared by Paul et al . [157] by melt - blending the matrix with 20 wt%

poly(ethyleneglycol) ( PEG ; number average molecular weight 1000) and different

amounts of MMT, with or without organomodiﬁ cation. For this, four different

(organo)clays were dispersed within the plasticized PLA matrix, after which the

inﬂ uence of the interlayer cations on the composite ’ s morphological and thermal

properties was studied while maintaining a constant level of inorganic material

(3 wt% layered aluminosilicate).

Each of the MMTs studied, including the unmodiﬁ ed sodium - MMT, led to the

formation of intercalated nanocomposites, Usually, melt - blending polymer matri-

ces with sodium MMT results in the formation of a microcomposite, as most of

the polymers are too highly hydrophobic to migrate into the hydrated Na

+

inter-

layer space. However, Vaia et al . [158] have reported on the intercalation of PEG

between the aluminosilicate layers of an unmodiﬁ ed sodium - MMT that led to an

increase in the interlayer distance which was similar to that observed by Paul

et al . [157] . Clearly, in the presence of sodium - MMT, the PEG 1000 is able to

intercalate preferentially with the interlayer spacing of the clay. This selective PEG

13.5 Conclusions 447

intercalation was further conﬁ rmed by an inability to form a nanocomposite by

melt - blending nonplasticized PLA with sodium - MMT.

At a constant ﬁ ller level it appears that, among all the clays studied (Cloisite

Na+, Cloisite 30B, Cloisite 20A, and Cloisite 15A; see Table 13.5 , rows a, b, and i,

respectively), the MMT that had been organomodiﬁ ed with bis - (2 - hydroxyethyl) -

methyl - (hydrogenated tallow alkyl) ammonium cations (Cloisite 30B) brought

about a greater effect in terms of improvements in dispersion level and thermal

stability of the plasticized nanocomposites, and this was in good agreement with

previous reports of PLA/MMT nanocomposites. It was noted, however, by using

WAXS and DSC analyses, that there existed a real competition between PEG 1000

and PLA for intercalation into the interlayer spacing of the clay.

As also noted by Pluta et al . [159] , who investigated the same system, SEC

revealed a decrease in the molecular weight of the PLA matrix. This was more

consistent at higher ﬁ ller contents, but essentially independent of the type of

organophilic modiﬁ cation of the MMT.

Thellen et al . [160] investigated the inﬂ uence of MMT - layered silicate on plasti-

cized PLA blown ﬁ lms. Here, the plasticized PLA MMT - layered silicate nanocom-

posites were compounded and blown ﬁ lm - processed, using a co - rotating,

twin - screw extruder. The PLA was mixed with 10 wt% acetyltriethyl citrate ester as

plasticizer and 5 wt% of an OMMT, at various screw speeds. Both, WAXD and

TEM investigations showed that the compounded pellets and the blown - ﬁ lm PLA/

OLS nanocomposites had intercalated. The effects of the processing screw speed

on the barrier, thermal, mechanical, and biodegradation properties of the nano-

composites were also considered, and compared to the neat polymer. The nano-

composite ﬁ lms showed a 48% improvement in oxygen barrier, and a 50%

improvement in water vapor barrier, when compared to PLA. A subsequent TGA

revealed an overall 9 ° C increase in the decomposition temperature for all of the

nanocomposites. A DSC analysis indicated that neither the glass transition, cold

crystallization, nor melting point temperature was signiﬁ cantly inﬂ uenced by the

presence of MMT. The mechanical properties of the nanocomposites indicated a

20% increase in the Young ’ s modulus, but that the ultimate elongation of the

nanocomposites had not been sacriﬁ ced compared to the neat samples. Hence,

the use of both plasticizers and nanoﬁ llers in a PLA matrix might effectively serve

as a successful strategy for providing materials with modulated properties.

13.5

Conclusions

In this chapter we have compared the schemes used to prepare polymer/layered

silicate nanocomposites from three classes of material, namely polyoleﬁ ns, PET

and PLA, and have reviewed certain interesting similarities and differences among

these materials.

With regards to similarities, analogous synthetic approaches were described for

the preparation of nanocomposites, with all three cases – in situ polymerization,

448 13 Nanocomposites Based on Phyllosilicates

intercalation from solution, and intercalation in the melt – being investigated. For

polyoleﬁ ns, in situ polymerization appears less successful and less sustainable,

with synthesis via catalytic polymerization perhaps proving to be a drawback,

notably due to poor interactions between the inorganic ﬁ ller and the polymeric

matrix. To overcome this problem, the synthesis should include polyoleﬁ ns

bearing polar groups capable of interacting with the silicate layers. Many chal-

lenges remain, however. The catalytic polymerization of polar monomers with

both traditional Ziegler – Natta and metallocene catalysts is not feasible, due mainly

to catalyst deactivation, while the polymerization of polyesters via ROP onto

layered silicates represents an interesting strategy for developing highly compati-

bilized organic – inorganic hybrid systems. The hydroxyl groups, whether typical of

phyllosilicates or purposefully added via modiﬁ cation with hydroxyethyl functional

ammonium salts, serve as initiating sites for the polymerization of lactide, or

various lactones. Most importantly, polymerizations must be strictly controlled,

with the length of the grafted chains being longer than the critical molecular

weight of any chain entanglements.

Today, the number of reports describing the preparation of polyoleﬁ n - based

nanocomposites exceeds that on the preparation of PET and PLA nanocomposites,

essentially because preparing nanocomposites from polyoleﬁ ns is much more

difﬁ cult due to intrinsic incompatibilities between the polar matrix and the highly

polar ﬁ ller. Whilst for polyoleﬁ n - based nanocomposites, extensive data have been

acquired by using apolar organophilic layered silicates, in the case of PET, exfoli-

ated silicate nanocomposites were acquired via an extrusion process which utilized

a nonmodiﬁ ed sodium - MMT.

It seems that the best structure for a modiﬁ cation agent depends on the

polarity of the polymeric matrix. In the case of polyoleﬁ ns, ammonium salts

with long aliphatic chains can permit optimization of the dispersion level. For

PLA, the methyl, hydrogenated tallow, bis(hydroxyethyl) ammonium salt seems

to be the best dispersing agent for clay, whereas for PET, sodium - MMT, hydro-

genated tallow, bis(hydroxyethyl) ammonium - MMT and dimethyl, hydrogenated

tallow, benzyl ammonium - MMT, are each capable of providing exfoliated

morphologies.

Another crucial point here is the need to use a compatibilizer. When preparing

polyoleﬁ n/layered silicate nanocomposites, the addition of a compatibilizer is

paramount, yet for PLA and PET nanocomposites the inclusion of a compatibilizer

is rare. Thus, the polarity of a polymer matrix seems to be the main driving force

of the preparation strategy, as summarized in Figure 13.14 .

In general, the preparation of polymer/layered silicate nanocomposites requires

parallel investigations concerning compatibilizers and processing aids. For poly-

oleﬁ n - based nanocomposites, the challenge resides in setting up and understand-

ing the role of reactive compatibilizers to control and/or tailor the morphologies

responsible for the improved material properties. But, for PET the main objective

is – and will continue to be – the optimization of thermal stability, as organophilic

modiﬁ ers are typically unstable at PET processing temperatures. Undoubtedly,

improvements in the thermal stability and ﬂ ame self - extinguishing properties of

Acknowledgments 449

PET will become technological necessities, notably in the development of new

ﬁ bers and the preparation of nanocomposites. Meanwhile, PET recycling and the

need to improve the properties of post - consumer materials remain major chal-

lenges for PET/layered silicate nanocomposites.

For PLA, and for biodegradable polyesters in general, new processing aids – devel-

oped from renewable resources – should be selected when preparing nanocom-

posites. Whilst the criteria of nanocomposite preparation are substantially similar

to those for petrochemical polymers, the (preferential) need to use naturally

derived compounds and polymers will surely lead to innovative methods of pro-

duction. In particular, replacing commonly used commercial modiﬁ ers (ammo-

nium salts) with cations that are not only more sustainable but also biodegradable

should prove interesting. In attempts to develop new materials with modulated

properties, melt - blending with biodegradable and/or renewable polymers, or

perhaps the addition of highly sustainable plasticizers, should allow for the crea-

tion of innovative materials that are highly tunable in terms of their mechanical,

thermal, gas - barrier, and biodegradation properties. Clearly, the behavior of

nanolayers in a complex multiphase system will remain the object of increasing

research attention for years to come.

Acknowledgments

The authors thank Prof. Francesco Ciardelli, Stefania Castiello and Francesca

Signorini (Dipartimento di Chimica e Chimica Industriale, Universit à di Pisa) for

very helpful discussions. Financial support from MIUR (NANOPACK FIRB 2003

Figure 13.14 Schematic comparison of preparation methods

for polymer/layered silicates nanocomposites.

450 13 Nanocomposites Based on Phyllosilicates

D. D. 2186 grant RBNE03R78E) and from CIPE (Toscana PC - RIPLAS project,

2008 – 2009) is also gratefully acknowledged.

References

1 Gao , F. ( 2004 ) Clay/polymer composites:

the story . Mater. Today , 7 , 50 – 5 .

2 Zeng , Q.H. , Yu , A.B. , Lu , G.Q. and Paul ,

D.R. ( 2005 ) Clay - based polymer

nanocomposites: research and

commercial development . J. Nanosci.

Nanotechnol. , 5 , 1574 – 1592 .

3 Schadler , L.S. , Brinson , L.C. and Sawyer ,

W.G. ( 2007 ) Polymer nanocomposites: a

small part of the story . JOM , 3 , 53 – 60 .

4 Yu , L. , Dean , K. and Li , L. ( 2006 )

Polymer blends and composites from

renewable resources . Prog. Polym. Sci. ,

31 , 576 – 602 .

5 Tsutsumi , N. , Kono , Y. , Oya , M. , Sakai ,

W. and Nagata , M. ( 2008 ) Recent

development of biodegradable network

polyesters obtained from renewable

natural resources . Clean Soil, Air, Water ,

36 , 682 – 686 .

6 Grim , R.E. ( 1968 ) Clay Mineralogy , 2nd

edn , McGraw - Hill , New York, NY, USA .

7 Manocha , L.M. ( 2006 ) Composites with

nanomaterials , in Functional

Nanomaterials (eds K.E. Geckeler and E.

Rosemberg ), American Scientiﬁ c

Publishers , Stevenson Ranch, CA, USA .

8 Dong , H. ( 2005 ) Interstratiﬁ ed

illite - smectite: a review of contributions

of TEM data to crystal chemical relations

and reaction mechanisms . Clay Sci. , 12

( Suppl. 1 ), 6 .

9 Carnicelli , S. , Mirabella , A. , Cecchini , G.

and Sanesi , G. ( 1997 ) Weathering of

chlorite to a low charge expandable

mineral in a spodosol on the Apennine

Mountains, Italy . Clays Clay Miner. , 45 ,

28 .

10 Sakharov , B.A. , Lindgreen , H. , Salyn , A.

and Drits , V.A. ( 1999 ) Determination of

illite - smectite structures using

multispecimen X - ray diffraction proﬁ le

ﬁ tting . Clays Clay Miner. , 47 ( 5 ),

555 – 569 .

11 Xu , W.B. , Ge , M.L. and He , P.S. ( 2001 )

Nonisothermal crystallization kinetics of

polyoxymethylene/montmorillonite

nanocomposites . J. Appl. Polym. Sci. , 82 ,

2281 – 2297 .

12 Liu , J. , Boo , W. - J. , Clearﬁ eld , A. and Sue ,

H. - J. ( 2006 ) Intercalation and exfoliation:

a review on morphology of polymer

nanocomposites reinforced by inorganic

layer structures . Mater. Manufact.

Process. , 20 , 143 – 151 .

13 Sinha Ray , S. , Okamoto , K. and

Okamoto , M. ( 2003 ) Structure – property

relationship in biodegradable

poly(butylene succinate)/layered silicate

nanocomposites . Macromolecules , 36 ,

2355 .

14 Chen , B. , Evans , J.R.G. , Greenwell , H.C. ,

Boulet , P. , Coveney , P.V. , Bowden , A.A.

and Whiting , A. ( 2008 ) A critical

appraisal of polymer – clay

nanocomposites . Chem. Soc. Rev. , 37 ,

568 – 594 .

15 Samyn , F. , Bourbigot , S. , Jama , C. ,

Bellayer , S. , Nazare , S. , Hull , R. ,

Castrovinci , A. , Fina , A. and Camino , G.

( 2008 ) Crossed characterisation of

polymer - layered silicate (PLS)

nanocomposite morphology: TEM, X - ray

diffraction, rheology and solid - state

nuclear magnetic resonance

measurements . Eur. Polym. J. , 44 ,

1642 – 1653 .

16 Luo , Z.P. and Koo , J.H. ( 2008 )

Quantiﬁ cation of the layer dispersion

degree in polymer layered silicate

nanocomposites by transmission

electron microscopy . Polymer , 49 ,

1841 – 1852 .

17 Drummy , L.F. , Wang , Y.C. ,

Schoenmakers , R. , May , K. , Jackson , M. ,

Koerner , O.H. , Farmer , B.L. , Mauryama ,

B. and Vaia , R.A. ( 2008 ) Morphology of

layered silicate - (NanoClay - ) polymer

nanocomposites by electron tomography

and small - angle X - ray scattering .

Macromolecules , 41 , 2135 – 2143 .

18 Incarnato , L. , Scarfato , P. , Scatteia , L.

and Acierno , D. ( 2004 ) Rheological

behavior of new melt compounded

References 451

copolyamide nanocomposites . Polymer ,

45 ( 10 ), 3487 – 3496 .

19 Lim , S.K. , Kim , J.W. , Chin , I. , Kwon ,

Y.K. and Choi , H.J. ( 2002 ) Preparation

and interaction characteristics of

organically modiﬁ ed montmorillonite

nanocomposite with miscible polymer

blend of poly(ethylene oxide) and

poly(methyl methacrylate) . Chem. Mater. ,

14 , 1989 – 1994 .

20 Kim , H.B. , Choi , J.S. , Lee , C.H. , Lim ,

S.T. , Jhon , M.S. and Choi , H.J. ( 2005 )

Polymer blend/organoclay

nanocomposite with poly(ethylene oxide)

and poly(methyl methacrylate) . Eur.

Polym. J. , 41 , 679 – 685 .

21 Ray , S.S. , Pouliot , S. , Bousmina , M. and

Utracki , L.A. ( 2004 ) Role of organically

modiﬁ ed layered silicate as an active

interfacial modiﬁ er in immiscible

polystyrene/polypropylene blends .

Polymer , 45 , 8403 – 8413 .

22 Fang , Z. , Harrats , C. , Moussaif , N. and

Groeninckx , G. ( 2007 ) Location of a

nanoclay at the interface in an

immiscible poly( ε - caprolactone)/

poly(ethylene oxide) blend and its effect

on the compatibility of the components .

J. Appl. Polym. Sci. , 106 , 3125 – 3135 .

23 Gahleitner , M. , Kretzschmar , B. ,

Pospiech , D. , Ingolic , E. , Reichelt , N.

and Bernreitner , K. ( 2006 ) Morphology

and mechanical properties of

polypropylene/polyamide 6

nanocomposites prepared by a two - step

melt - compounding process . J. Appl.

Polym. Sci. , 100 , 283 – 291 .

24 Vo , L.T. and Giannelis , E.P. ( 2007 )

Compatibilizing poly(vinylidene

ﬂ uoride)/nylon - 6 blends with nanoclay .

Macromolecules , 40 , 8271 – 8276 .

25 Yurekli , K. , Karim , A. , Amis , E.J. and

Krishnamoorti , R. ( 2003 ) Inﬂ uence of

layered silicates on the phase - separated

morphology of PS - PVME blends .

Macromolecules , 36 , 7256 – 7257 .

26 Filippone , G. , Dintcheva , N.T. , Acierno ,

D. and La Mantia , F.P. ( 2008 ) The role

of organoclay in promoting co -

continuous morphology in high - density

poly(ethylene)/poly(amide) 6 blends .

Polymer , 49 , 1312 – 1322 .

27 Chow , W.S. , Mohd Ishak , Z.A. ,

Karger - Kocsis , J. , Apostolov , A.A. and

Ishiaku , U.S. ( 2003 ) Compatibilizing

effect of maleated polypropylene on

the mechanical properties and

morphology of injection molded

polyamide 6/polypropylene/organoclay

nano composite . Polymer , 44 , 7427 –

7440 .

28 Chow , W.S. , Abu Bakar , A. , Mohd Ishak ,

Z.A. , Karger - Kocsis , J. and Ishiaku , U.S.

( 2005 ) Effect of maleic anhydride - grafted

ethylene – propylene rubber on the

mechanical, rheological and

morphological properties of organoclay

reinforced polyamide 6/polypropylene

nanocomposites . Eur. Polym. J. , 41 ,

687 – 696 .

29 Chow , W.S. , Mohd Ishak , Z.A. and

Karger - Kocsis , J. ( 2005 ) Atomic force

microscopy study on blend morphology

and clay dispersion in polyamide - 6/

polypropylene/organoclay systems .

J. Polym. Sci., Part B: Polym. Phys. , 43 ,

1198 – 1204 .

30 Chen , G.X. and Yoon , J.S. ( 2005 )

Thermal stability of poly(L - lactide)/

poly(butylene succinate)/clay

nanocomposites . Polym. Degrad. Stab. ,

88 , 206 – 212 .

31 Pavlidou , S. and Papaspyrides , C.D.

( 2008 ) A review - layered silicate

nanocomposites . Prog. Polym. Sci. , 33 ,

1190 – 1198 .

32 Passaglia , E. , Bertoldo , M. , Ceriegi , S. ,

Sulcis , R. , Narducci , P. and Conzatti , L.

( 2008 ) Oxygen and water vapor barrier

properties of MMT nanocomposites

from low density polyethylene or EPM

with grafted succinic groups . J. Nanosci.

Nanotechnol. , 8 ( 4 ), 1690 – 1699 .

33 Lu , C. and Mai , Y. - W. ( 2005 ) Inﬂ uence

of aspect ratio on barrier properties of

polymer - clay nanocomposites . Phys. Rev.

Lett. , 95 , 088303 .

34 Xu , B. , Zheng , Q. , Song , Y. and

Shangguan , Y. ( 2006 ) Calculating barrier

properties of polymer/clay

nanocomposites: effects of clay layers .

Polymer , 47 , 2904 – 2910 .

35 Rittigstein , P. , Priestley , R.D. , Broadbelt ,

L.J. and Torkelson , J.M. ( 2007 ) Model

polymer nanocomposites provide an

understanding of conﬁ nement effects in

real nanocomposites . Nat. Mater. , 6 ( 4 ),

257 – 258 .

452 13 Nanocomposites Based on Phyllosilicates

36 Gilman , J.W. , Jackson , C.L. , Morgan ,

A.B. , Harris , R. Jr. , Manias , E. ,

Giannelis , E.P. , Wuthenow , M. , Hilton ,

D. and Phillips , S.H. ( 2000 )

Flammability properties of polymer -

layered - silicate nanocomposites.

Polypropylene and polystyrene

nanocomposites . Chem. Mater. , 12 ,

1866 – 1873 .

37 Zanetti , M. , Kashiwagi , T. , Falqui , L. and

Camino , G. ( 2002 ) Cone calorimeter

combustion and gasiﬁ cation studies of

polymer layered silicate nanocomposites .

Chem. Mater. , 14 , 881 – 887 .

38 Liu , T. , Lim , K.P. , Tjiu , W.C. , Pramoda ,

K.P. and Chen , Z. - K. ( 2003 ) Preparation

and characterization of nylon 11/

organoclay nanocomposites . Polymer , 44 ,

3529 – 3535 .

39 Harrats , C. and Groeninckx , G. ( 2008 )

Features, questions and future

challenges in layered silicates clay

nanocomposites with semicrystalline

polymer matrices . Macromol. Rapid.

Commun. , 29 , 14 – 26 .

40 Xu , W. , Ge , M. and He , P. ( 2001 )

Nonisothermal crystallization kinetics of

polyoxymethylene/montmorillonite

nanocomposite . J. Appl. Polym. Sci. , 82 ,

2281 – 2289 .

41 Giannelis , E.P. , Krishnamoorti , R. and

Manias , E. ( 1999 ) Polymer - silicate

nanocomposites: model systems for

conﬁ ned polymers and polymer brushes .

Adv. Polym. Sci. , 138 , 107 – 147 .

42 Alexandre , M. and Dubois , P. ( 2000 )

Polymer - layered silicate nanocomposites:

preparation, properties and uses of a

new class of materials . Mater. Sci. Eng.,

R , R28 , 1 – 63 .

43 Pinnavaia , T.J. and Beall , G.W. ( 2000 )

Polymer - Clay Nanocomposites , John Wiley

& Sons, Inc. , New York .

44 Fischer , H. ( 2003 ) Polymer

nanocomposites: from fundamental

research to speciﬁ c applications . Mater.

Sci. Eng., C , C23 , 763 – 772 .

45 Ray , S.S. and Okamoto , M. ( 2003 )

Polymer/layered silicate nanocomposites:

a review from preparation to processing .

Prog. Polym. Sci. , 28 , 1539 – 1641 .

46 Giannelis , E. ( 1996 ) Polymer layered

silicate nanocomposites . Adv. Mater. , 8 ,

29 – 35 .

47 Tjong , S.C. ( 2006 ) Structural and

mechanical properties of polymer

nanocomposites . Mater. Sci. Eng., R ,

R53 , 73 – 197 .

48 Ciardelli , F. , Coiai , S. , Passaglia , E. ,

Pucci , A. and Ruggeri , G. ( 2008 )

Nanocomposites based on polyoleﬁ ns

and functional thermoplastic materials .

Polym. Int. , 57 , 805 – 836 .

49 Vaia , R.A. , Price , G. , Ruth , P.N. ,

Nguyen , H.T. and Lichtenhan , J. ( 1999 )

Polymer/layered silicate nanocomposites

as high performance ablative materials .

J. Appl. Clay. Sci. , 15 , 67 – 92 .

50 Biswas , M. and Sinha Ray , S. ( 2001 )

Recent progress in synthesis and

evaluation of polymer - montmorillonite

nanocomposites . Adv. Polym. Sci. , 155 ,

167 – 221 .

51 Kawasumi , M. , Hasegawa , N. , Kato , M. ,

Usuki , A. and Okada , A. ( 1997 )

Preparation and mechanical properties

of polypropylene - clay hybrids .

Macromolecules , 30 , 6333 – 6338 .

52 Manias , E. , Touny , A. , Wu , L. ,

Strawhecker , K. , Lu , B. and Chung , T.C.

( 2001 ) Polypropylene/montmorillonite

nanocomposites. Review of the synthetic

routes and materials properties . Chem.

Mater. , 13 , 3516 – 3523 .

53 Liu , X.H. and Wu , Q.J. ( 2001 )

Polypropylene/clay nanocomposites

prepared by grafting - melt . Polymer , 42 ,

10013 – 10019 .

54 Garc í a - L ó pez , D. , Picazo , O. , Merino ,

J.C. and Pastor , J.M. ( 2003 )

Polypropylene - clay nanocomposites:

effect of compatibilizing agents on clay

dispersion . Eur. Polym. J. , 39 , 945 – 950 .

55 Usuki , A. , Kato , M. , Okada , A. and

Kurauchi , T. ( 1997 ) Synthesis of

polypropylene - clay hybrid . J. Appl. Polym.

Sci. , 63 , 137 – 139 .

56 Kato , M. , Usuki , A. and Okada , A. ( 1997 )

Synthesis of polypropylene oligomer - clay

intercalation compounds . J. Appl. Polym.

Sci. , 66 , 1781 – 1785 .

57 Oya , A. , Kurokawa , Y. and Yasuda , H.

( 2000 ) Factors controlling mechanical

properties of clay mineral/polypropylene

nanocomposites . J. Mater. Sci. , 35 ,

1045 – 1050 .

58 Wang , Y. , Chen , F.B. , Li , Y.C. and Wu ,

K.C. ( 2004 ) Melt processing of

References 453

polypropylene/clay nanocomposites

modiﬁ ed with maleated polypropylene

compatibilizers . Composites Part B , 35 ,

111 – 124 .

59 Sun , T. and Garc é s , M.J. ( 2002 )

High - performance polypropylene - clay

nanocomposites by in situ

polymerization with metallocene/

clay catalysts . Adv. Mater. , 14 , 128 –

130 .

60 Hwu , J.M. and Jiang , G.J. ( 2005 )

Preparation and characterization of

polypropylene - montmorillonite

nanocomposites generated by in situ

metallocene catalyst polymerization .

J. Appl. Polym. Sci. , 95 , 1228 – 1236 .

61 Ma , J.S. , Qi , Z.N. and Hu , Y.L. ( 2001 )

Synthesis and characterization of

polypropylene/clay nanocomposites .

J. Appl. Polym. Sci. , 82 , 3611 – 3617 .

62 He , A. , Hu , H. , Huang , Y. , Dong , J.Y.

and Han , C.C. ( 2004 ) Isotactic

poly(propylene)/monoalkylimidazolium -

modiﬁ ed montmorillonite

nanocomposites: preparation by

intercalative polymerization and thermal

stability study . Macromol. Rapid.

Commun. , 25 , 2008 – 2013 .

63 Alexandre , M. , Dubois , P. , Sun , T. ,

Garces , J.M. and Jerome , R. ( 2002 )

Polyethylene - layered silicate

nanocomposites prepared by the

polymerization - ﬁ lling technique:

synthesis and mechanical properties .

Polymer , 43 , 2123 – 2132 .

64 Osman , M.A. , Rupp , J.E.P. and Suter ,

U.W. ( 2005 ) Effect of non - ionic

surfactants on the exfoliation and

properties of polyethylene - layered silicate

nanocomposites . Polymer , 46 ,

8202 – 8209 .

65 Vaia , R.A. and Giannelis , E.P. ( 1997 )

Lattice model of polymer melt

intercalation in organically - modiﬁ ed

layered silicates . Macromolecules , 30 ,

7990 – 7999 .

66 Vaia , R.A. and Giannelis , E.P. ( 1997 )

Polymer melt intercalation in

organically - modiﬁ ed layered silicates:

model predictions and experiment .

Macromolecules , 30 , 8000 – 8009 .

67 Rogers , K. , Takacs , E. and Thompson ,

M.R. ( 2005 ) Contact angle measurement

of select compatibilizers for polymer -

silicate layer nanocomposites . Polym.

Test. , 24 , 423 – 427 .

68 Borsacchi , S. , Geppi , M. , Ricci , L. ,

Ruggeri , G. and Veracini , C.A. ( 2007 )

Interactions at the surface of

organophilic - modiﬁ ed laponites: a

multinuclear solid - state NMR study .

Langmuir , 23 , 3953 – 3960 .

69 K à d à r , F. , Sz à zdi , L. , Fekete , E. and

Puk à nszky , B. ( 2006 ) Surface

characteristics of layered silicates:

inﬂ uence on the properties of clay/

polymer nanocomposites . Langmuir , 22 ,

7848 – 7854 .

70 Balazs , A.C. , Singh , C. and Zhulina , E.

( 1998 ) Modeling the interactions

between polymers and clay surfaces

through self - consistent ﬁ eld theory .

Macromolecules , 31 , 8370 – 8381 .

71 Balazs , A.C. , Singh , C. , Zhulina , E. and

Lyatskaya , Y. ( 1999 ) Modelling the phase

behaviour of polymer/clay

nanocomposites . Acc. Chem. Res. , 32 ,

651 – 657 .

72 Wang , K.H. , Choi , M.H. , Koo , C.M. ,

Choi , Y.S. and Chung , I.J. ( 2001 )

Synthesis and characterization of

maleated polyethylene/clay

nanocomposites . Polymer , 42 ,

9819 – 9826 .

73 Koo , C.M. , Ham , H.T. , Kim , S.O. , Wang ,

K.H. and Chung , I.J. ( 2002 ) Morphology

evolution and anisotropic phase

formation of the maleated polyethylene -

layered silicate nanocomposites .

Macromolecules , 35 , 5116 – 5122 .

74 Wang , Z.M. , Nakajima , H. , Manias , E.

and Chung , T.C. ( 2003 ) Exfoliated PP/

Clay nanocomposites using ammonium -

terminated PP as the organic

modiﬁ cation for montmorillonite .

Macromolecules , 36 , 8919 – 8922 .

75 Chrissopoulou , K. , Altintzi , I. ,

Anastasiadis , S.H. , Giannelis , E.P. ,

Pitsikalis , M. , Hadjichristidis , N. and

Theophilou , N. ( 2005 ) Controlling the

miscibility of polyethylene/layered

silicate nanocomposites by altering the

polymer/surface interactions . Polymer ,

46 , 12440 – 12451 .

76 Moad , G. , Dean , K. , Edmond , L. ,

Kukaleva , N. , Li , G. , Mayadunne , R.T.A. ,

Pfaendner , R. , Schneider , A. , Simon ,

G.P. and Wermter , H. ( 2006 ) Non - ionic,

454 13 Nanocomposites Based on Phyllosilicates

poly(ethylene oxide) - based surfactants as

intercalants/dispersants/exfoliants for

poly(propylene) - clay nanocomposites .

Macromol. Mater. Eng. , 291 , 37 – 52 .

77 Hasegawa , N. , Kawasumi , M. , Kato , M. ,

Usuki , A. and Okada , A. ( 1998 )

Preparation and mechanical properties

of polypropylene - clay hybrids using a

maleic anhydride - modiﬁ ed

polypropylene oligomer . J. Appl. Polym.

Sci. , 67 , 87 – 92 .

78 Hasegawa , N. , Okamoto , H. , Kawasumi ,

M. , Kato , M. , Tsukigas , A. and Usuki , A.

( 2000 ) Polyoleﬁ n – clay hybrids based on

modiﬁ ed polyoleﬁ ns and organoclay .

Macromol. Mater. Eng. , 280/281 , 76 – 79 .

79 Moad , G. ( 1999 ) The synthesis of

polyoleﬁ n graft copolymers by reactive

extrusion . Prog. Polym. Sci. , 24 , 81 – 142 .

80 Passaglia , E. , Coiai , S. , Aglietto , M. ,

Ruggeri , G. , Rubert à , M. and Ciardelli ,

F. ( 2003 ) Functionalization of polyoleﬁ ns

by reactive processing: inﬂ uence of

starting reagents on content and type of

grafted groups . Macromol. Symp. , 198 ,

147 – 160 .

81 Ciardelli , F. , Aglietto , M. , Coltelli , M.B. ,

Passaglia , E. , Ruggeri , G. and Coiai , S.

( 2004 ) Functionalization of polyoleﬁ ns in

the melt , in Modiﬁ cation and Blending of

Synthetic and Natural Macromolecules

(eds F. Ciardelli and S. Penczek ), Kluwer

Academic Publishers , The Netherlands .

82 Coiai , S. , Scatto , M. , Bertoldo , M. ,

Conzatti , L. , Andreotti , L. , Sterner , M. ,

Passaglia , E. , Costa , G. and Ciardelli , F.

( 2009 ) Study of the compounding

process parameters for morphology

control of LDPE/layered silicate

nanocomposites . e - polymers , accepted.

83 Passaglia , E. , Sulcis , R. , Ciardelli , F. ,

Malvaldi , M. and Narducci , P. ( 2005 )

Effect of functional groups of modiﬁ ed

polyoleﬁ ns on the structure and

properties of their composites with

lamellar silicates . Polym. Int. , 54 ,

1549 – 1556 .

84 Passaglia , E. , Bertoldo , M. , Ciardelli , F. ,

Prevosto , D. and Lucchesi , M. ( 2008 )

Evidences of macromolecular chains

conﬁ nement of ethylene - propylene

copolymer in organophilic

montmorillonite nanocomposites . Eur.

Polym. J. , 44 , 1296 – 1308 .

85 Passaglia , E. , Bertuccelli , W. and

Ciardelli , F. ( 2001 ) Composites from

functionalized polyoleﬁ ns and silica .

Macromol. Symp. , 176 , 299 – 315 .

86 Coiai , S. , Passaglia , E. , Aglietto , M. and

Ciardelli , F. ( 2004 ) Control of

degradation reactions during radical

functionalization of polypropylene in

the melt . Macromolecules , 37 , 8414 –

8423 .

87 Augier , S. , Coiai , S. , Gragnoli , T. ,

Passaglia , E. , Pradel , J.L. and Flat , J.J.

( 2006 ) Coagent assisted polypropylene

radical functionalization: monomer

grafting modulation and molecular

weight conservation . Polymer , 47 ,

5243 – 5252 .

88 Augier , S. , Coiai , S. , Pratelli , D. ,

Conzatti , L. and Passaglia , E. ( 2009 ) New

functionalized polypropylenes as

controlled architecture compatibilizers

for polypropylene layered silicates

nanocomposites . J. Nanosci.

Nanotechnol. , 9 , 4858 – 4869 .

89 Passaglia , E. , Bertoldo , M. , Coiai , S. ,

Augier , S. , Savi , S. and Ciardelli , F.

( 2008 ) Nanostructured polyoleﬁ ns/clay

composites: role of the molecular

interaction at the interface . Polym. Adv.

Technol. , 19 , 560 – 568 .

90 Ginzburg , V.V. and Balazs , A.C. ( 2000 )

Calculating phase diagrams for

nanocomposites: the effect of adding

end - functionalized chains to polymer/

clay mixtures . Adv. Mater. , 23 ,

1805 – 1809 .

91 Sinsawat , A. , Anderson , K.L. , Vaia , R.A.

and Farmer , B.L. ( 2003 ) Inﬂ uence of

polymer matrix composition and

architecture on polymer nanocomposite

formation: coarse - grained molecular

dynamics simulation . J. Polym. Sci., Part

B: Polym. Phys. , 41 , 3272 – 3284 .

92 Marchant , D. and Jayaraman , K. ( 2002 )

Strategies for optimizing polypropylene -

clay nanocomposite structure . Ind. Eng.

Chem. Res. , 41 , 6402 – 6408 .

93 Yang , K. and Ozisik , R. ( 2006 ) Effects of

processing parameters on the

preparation of nylon 6 nanocomposites .

Polymer , 47 , 2849 – 2855 .

94 Perrin - Sarazin , F. , Ton - That , M.T. ,

Bureau , M.N. and Denault , J. ( 2005 )

Micro - and nano - structure in

Geckeler K.E., Nishide H. (Eds.) Advanced Nanomaterials

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