Smectite-Polymer Nanocomposites

Chapter 13.1

Smectite–Polymer Nanocomposites J.-F. Lamberta and F. Bergayab a b

LRS, UMR 7197 CNRS, UPMC University Paris 6, 4 Pl. Jussieu 75252, Paris Cedex 05, France CRMD, CNRS-Universite´ d’Orleáns, Orleáns Cedex 2, France

Chapter Outline 13.1.1. Types of CPN and Domains of Application 681 13.1.1.1. Clay Mineral– Nylon as an Engineering or Structural Material 681 13.1.1.2. Clay Mineral– Epoxy Polymers as Structural Materials 681 13.1.1.3. Clay Mineral– Elastomers and the Rubber Industry 681 13.1.1.4. Clay Mineral– Polymers for Barrier Properties and Packaging 682 13.1.1.5. Clay Mineral– Biopolymer Nanocomposites and Green Chemistry 683 13.1.1.6. Clay Mineral– Biopolymers for

Biomedical Applications 686 13.1.1.7. Clay Mineral– Polymers and Optical Properties 687 13.1.1.8. Clay Mineral– Polymers for Electrical Properties: Ionic Conductivity and Fuel Cells 688 13.1.2. CPN Preparation Methods 689 13.1.2.1. Direct Polymer Intercalation in Clay Minerals (Solid-State Compounding or Solvent Casting) 689 13.1.2.2. Methods Based on Adjusting the Hydrophilic– Lipophilic Balance 689

Developments in Clay Science, Vol. 5A. http://dx.doi.org/10.1016/B978-0-08-098258-8.00021-3 © 2013 Elsevier Ltd. All rights reserved.

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13.1.2.3. In Situ Polymerization 691 13.1.2.4. PolymerTemplated Clay Mineral Synthesis 691 13.1.3. Interaction Mechanisms and Structure Characterization 692 13.1.3.1. Intercalated versus Exfoliated

Nanocomposites 692 13.1.3.2. Diversity of Smectites 693 13.1.3.3. Characterization Techniques 694 13.1.4. Conclusion 697 References 697

The first reports on clay–organic polymer nanocomposites date back to the early 1960s (Blumstein, 1961, 1965) when the polymerization of various monomers intercalated in smectites started being studied. The early literature on clay–polymer interactions is the subject of a book (Theng, 1979), but interest in these systems remained episodic until the 1990s, when clay–nylon nanocomposites were first reported (Kojima et al., 1993a,b; Messersmith and Giannelis, 1993a; Usuki et al., 1993); they were commercially launched only 4 years later. Clay–epoxy nanocomposites soon followed (Messersmith and Giannelis, 1993b; Lan and Pinnavaia, 1994), and these developments generated frantic activity in the domain as many different clay–polymer combinations were explored and their properties tested. Currently, about 400 full research papers appear annually on clay–polymer nanocomposites (CPN), representing about a quarter of the total literature on polymer nanocomposites. A number of review papers (Okada and Usuki, 1996; Giannelis et al., 1999; Lebaron et al., 1999; Alexandre and Dubois, 2000; Carrado, 2000; Zanetti et al., 2000; Biswas and Sinha Ray, 2001; Vaia and Giannelis, 2001; Ray and Okamoto, 2003a; Usuki and Hasegawa, 2005; Nguyen and Baird, 2006; Chen et al., 2008; Paul and Robeson, 2008; Pavlidou and Papaspyrides, 2008; Bitinis et al., 2011) as well as several books entirely devoted to the subject have appeared (Pinnavaia and Beall, 2000; Utracki, 2004; Thomas and Stephen, 2010; Galimberti, 2011). Originally, the vast majority of these studies concerned composites in which the inorganic component was a smectite, most often Mt. This chapter is devoted to smectite–polymer nanocomposites, with occasional mention of other TOT clay minerals. As regards the polymer component, a cursory look at the structures in Table 13.0.1 gives an idea of the wide diversity of polymeric compounds studied. In particular, some of them contain polar groups either in the backbone or in the side chains, while others are apolar. This distinction is very important since apolar polymers will have little chemical affinity,

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or compatibility, with the clay mineral, necessitating the application of special strategies for successful nanocomposite syntheses.

13.1.1 TYPES OF CPN AND DOMAINS OF APPLICATION While the industrial aspects form a separate chapter (Chapter 4.4 in Volume B), the only way to understand which CPN systems are studied and why is by having an idea of their main applications.

13.1.1.1 Clay Mineral–Nylon as an Engineering or Structural Material Nylon, a polyamide, is one of the first commercial synthetic polymers and is well known in everyday life. Its composites are often used as car components. Mt–nylon nanocomposites were synthesized in 1979, but with a high content of the clay mineral (50%). They did not exhibit very interesting properties. The breakthrough came when researchers at the Toyota research laboratory prepared Mt–nylon and other smectite–nylons containing only a few mass percent of clay minerals that had first been intercalated with aminolauric acid and showed that the resulting hybrid materials had excellent mechanical properties (Kojima et al., 1993b). These materials were marketed in the automobile industry only 4 years later. This story has been told several times (Okada and Usuki, 1996; Usuki and Hasegawa, 2005). Early on, the improvement in composite properties was attributed to a high dispersion of the clay mineral particles, in the nanometric range, so that the term ‘nanocomposites’ could be properly used.

13.1.1.2 Clay Mineral–Epoxy Polymers as Structural Materials Epoxy polymers or polyepoxides are used as adhesives (in which case the polymerization is triggered by the addition of a ‘hardener’) and as structural materials. In 1994, Pinnavaia and co-workers reported on organo–Mt–epoxy resin nanocomposite formulation (Lan and Pinnavaia, 1994; Wang and Pinnavaia, 1994; Lan et al., 1995). As in the case of nylon nanocomposites, previous cationic surfactant intercalation to yield organoclays was crucial in order to prepare well-dispersed nanocomposites, which then exhibited enhanced mechanical properties and thermal stability.

13.1.1.3 Clay Mineral–Elastomers and the Rubber Industry For a long time, fillers such as carbon black, glass fibres or even talc (not a smectite, but a TOT clay mineral) were added to elastomers (used for rubber manufacture) to improve their mechanical properties and density. However, this required rather high concentrations of about 20–30% of fillers. As a

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consequence, the viscosity of the mixture increased with respect to the pure polymer, with negative consequences such as decreased processability. In the wake of the success of nylon nanocomposites, it was thought that an improved dispersion of the clay mineral particles would result in the same improvements with low clay mineral loadings. The first attempts were reported by Okada and Usuki (1996) with NBR. Later on, Zhang et al. (2000) and Wang et al. (2000) published results on clay mineral–SBR nanocomposites, and in the 2000s, the number of studies grew exponentially. For details, two recent books may be consulted (Thomas and Stephen, 2010; Galimberti, 2011). As the name ‘elastomer’ implies, the chief property here is (visco)elasticity, which is quantitatively measured by the Young’s modulus (or tensile modulus), that is, the ratio of the uniaxial stress applied to the material to the uniaxial strain that it undergoes (Fu et al., 2008). In other words, it tells us how hard the material has to be stressed in order to be deformed by a given amount. The Young’s modulus has the dimension of a pressure, typical values being a few gigapascals. Alternatively, the stress values may be given for several strains if the curve is not supposed to be linear. Many studies have demonstrated spectacular improvements in the Young’s modulus upon addition of a few mass percent of smectites, that is, the polymers became stiffer. For instance, a three- to fourfold increase was obtained for Mt–NR (Arroyo et al., 2003) as compared to the pristine NR. Related mechanical parameters are the tensile strength (maximum uniaxial stress that the material can sustain before breaking), the tensile elongation at break and the ‘fracture toughness’, that relates the crack size to the fracture strength. All of them can be improved by the formation of polymer nanocomposites with clay minerals. Beyond mechanical properties, flame retardancy is an additional benefit of clay mineral addition to the polymer matrix. One of the first articles to note this fact is by Gilman (1999). Porter et al. (2000) hypothesised that fire retardancy could be due to the structure of the char formed during combustion, which thermally insulates the polymer and thus inhibits the escape of volatiles.

13.1.1.4 Clay Mineral–Polymers for Barrier Properties and Packaging Messersmith and Giannelis (1995) had already reported that mica–PCL nanocomposites exhibited a reduction in water permeability as compared to the pristine polymer, and that this effect was proportional to the amount of clay mineral. A very similar behaviour was reported for the diffusion of water and CH2Cl2 in Mt–PCL (Tortora et al., 2002) as well as for water in Mt–PU (Osman et al., 2003). The subject of CPN permeability was reviewed by Choudalakis and Gotsis (2009), mostly from a theoretical point of view. One intuitively understandable idea is that molecules diffusing in the

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Clay layer or particle

Path of diffusing molecule FIGURE 13.1.1 A simple physical picture of why the diffusion of molecules is hampered in clay nanocomposites. In this view, the mere presence of the clay mineral particles acts as a barrier to molecule diffusion, irrespective of the nature of clay–polymer interaction.

polymer will be slowed by increasing tortuosity as they meet essentially impermeable clay mineral layers in their path through the polymer and have to find a way around them (Fig. 13.1.1). A vermiculite-based nanocomposite also showed decreased permeability for CO2 compared to the pristine polymer (Takahashi et al., 2006). A direct exploitation of the good barrier properties of CPN is their use in food packaging. In this case, the polymer component would ideally be ‘ecologically friendly’, that is, biodegradable. The candidate polymers usually have poor mechanical and barrier properties in the pristine state, so the improvements imparted by nanocomposites are particularly welcome (De Azeredo, 2009; Arora and Padua, 2010). The reviews by Rhim (2007) and De Azeredo (2009) contain information on industrial developments in this young field, and more information can be found in Bergaya and Lagaly (2007).

13.1.1.5 Clay Mineral–Biopolymer Nanocomposites and Green Chemistry As stated in the previous paragraph, some polymers may be considered as ‘green’ because they are biodegradable (Krikorian and Pochan, 2003; Ray and Okamoto, 2003b; Bordes et al., 2009) or otherwise biocompatible in some way. Such polymers include many biopolymers, that is, materials synthesized by living beings. Caution is in order, however. Biodegradability is ultimately a biochemical property correlated with the reactivity for ‘digesting’ enzymes. Polymers having oxygen atoms in their backbone, that is, ethers or esters, are usually biodegradable. Among these are ‘agropolymers’ such as starch or cellulose (or PHA obtained by microbial production) and also several man-made polymers such as PLA. However, the biopolymer lignin in wood is resistant to biological degradation except by some specialised fungi and bacteria.

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A further question related to environmental friendliness, independent of biodegradability, is whether the polymers are made from renewable or nonrenewable resources. Thus, PLA is manufactured from monomers produced from the agriculture and may therefore be considered as sustainable. Altogether, there is a big potential for the use of CPN in green chemistry applications, as espoused in a famous paper (Ray and Bousmina, 2005). Such CPN may be called bionanocomposites: a good review on bionanocomposites (not limited to clay mineral fillers) was provided by Darder et al. (2007), and a full book on this subject has already appeared (Ave´rous and Pollet, 2012). In addition, CPN have been discussed in some detail in a more general book on inorganic bionanocomposites (Ruiz-Hitzky et al., 2008).

13.1.1.5.1 Polysaccharides Polysaccharides are among the most prominent biopolymers. Thermoplastics can be obtained from starch and Mt, organo-Mt (Park et al., 2002) or Ht (Chen and Evans, 2005), provided a plasticizer such as glycerol is added (Magalhaes and Andrade, 2009). Thermoplastic materials were also prepared from starch, PCL and Mt (Vertuccio et al., 2009). Cellulose is another polysaccharide, with an average of about 1500 b-glucose units per chain. The corresponding nanocomposites with clay minerals were recently studied (Park et al., 2004). Cellulose filaments or whiskers isolated from marine tunicates (Capadona et al., 2007) can form aerogels that are attractive as ultra-low-density construction or engineering materials. Unfortunately, they have little physical resistance and are sponge-like. Mixing these cellulose whiskers with clay mineral particles at a very high clay content (mass ratio clay mineral/ cellulose ¼ 3/1) yielded more stable aerogels, which were considered as ‘nanoscale wattle-and-daub’ (Gawryla et al., 2009). In a completely different application, clay mineral–cellulose nanocomposites (mass ratio ¼ 2/1) were used as reusable adsorbents for chromate ions, which are a dangerous pollutant (Kumar et al., 2012). Thus, bionanocomposites broaden the composition range of clay mineral–polymer composites as compared to classical clay mineral–polymer composites. High-purity cellulose need not be used to prepare nanocomposite materials. Low added-value starting materials may be used: wood flour and PE were compounded with organoclay minerals by Lei et al. (2007). Cotton dissolved in morpholine oxide as solvent allowed the preparation of Mt–cellulose nanocomposites (White, 2004). Starting with apple peel pectin (a complex mixture of polysaccaharides), a Mt–pectin nanocomposite (3% Mt) with good mechanical and barrier properties was prepared (Mangiacapra et al., 2006). Other polysaccharides derived from natural sustainable sources are obtained from algae. Mt–ulvan nanocomposites were formed from ulvan of green algae, a sulphate-functionalized polysaccharide, with clay mineral/

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polymer ratios of 1/1–5/1 (i.e. 50–84 mass% of the clay mineral (Laza et al., 2007). These materials are now commercialised as food additives, as they are able to adsorb various toxins in the digestive tract. Green algae are abundant, but their seasonal blooms are a major source of water pollution that has to be treated and produces unwanted waste. Sodium alginate was also derived from algae and used for pervapouration membranes, where the addition of 5–10% Mt improved water selectivity (Bhat and Aminabhavi, 2006). Finally, agar, a gelatinous substance obtained by boiling red algae, and mostly containing agarose, a polymer of galactose, was compounded with Naþ-Mt to obtain nanocomposite films (Rhim, 2011). Chitosan is another modification of polysaccharides, characterised by protonable amine groups (as opposed to the negatively charged sulphonates of ulvan). Chitosan can be adsorbed by smectites in excess of the CEC. Thus, the formation of chitosan nanocomposites has the potential to turn smectites into anion exchangers (Darder et al., 2003). Qiu et al. (2005) used Mt–chitosan to promote acrylate adsorption and its polymerization into Mt–chitosan–PAA nanocomposites, which were used as super-adsorbents. Biopolymers may be submitted to chemical transformations in the process of nanocomposite synthesis. Darder and Ruiz-Hitzky (2005) reported that intercalative polycondensation of sucrose in Mt formed ‘Mt–caramel’ nanocomposites, which could then be transformed into porous clay mineral–carbon nanocomposites. Thus, in addition to dimer condensation, a more complex sugar chemistry was established similar to reactions rather well known in food chemistry. Also inspired by food chemistry, ‘Mt–melanoidin’ nanocomposites were obtained by the Maillard reaction between tyrosine and glutamate (Vicente Vilas et al., 2010). Interestingly, this CPN was proposed as a good model of clay mineral–humic acid nanocomposites existing in soils.

13.1.1.5.2 Other Biopolymers Another important group of biopolymers comprises the proteins, and some proteins are abundantly available from agricultural products or other cheap sources. For instance, gelatin is a mixture of peptides and protein prepared from the fibrous protein collagen and is easily available from animal waste. Clay mineral–gelatin nanocomposites were prepared by Darder et al. (2006). Other source materials such as soy protein (Rhim et al., 2005), silk fibroin (Dang et al., 2010) and wheat gluten (Olabarrieta et al., 2006) were also used with success. Clay mineral–protein nanocomposites were discussed in some detail by Zhao et al. (2008). Before the concept of CPN was developed, smectite–protein interactions were known to be highly relevant for soil science (Theng, 1982), and clay mineral–gelatin interactions, for instance, were already studied 60 years ago (Talibudeen, 1950). Special mention must be made of melanin, or pseudomelanin, which is formed by polymerization of L-DOPA, an amino acid. They are not proteins

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because the polymerization mechanism is not through amide bond formation. Nanocomposites of melanin and pseudomelanin (Jaber et al., 2011) and the related polydopamine (Yang et al., 2011) were formed with saponite and laponite. The last important biopolymers are RNA and DNA. They are used for hightechnology applications. Since they are polyanions, they preferentially interact with LDH (Choy et al., 2007). Nevertheless, significant interaction of various kinds of nucleic acids with Mt has been observed (Franchi et al., 1999).

13.1.1.6 Clay Mineral–Biopolymers for Biomedical Applications Biomedical technology constitutes an exponentially growing field, and CPN play a key role since they allow molecular-level tuning of their properties. The polymers involved may be the same as in the preceding paragraph but this application requires ‘smart’ materials in very small quantities. One of the advantages of clay minerals, namely, their low cost, is then not so crucial, but their excellent biocompatibility remains an asset. Clay minerals themselves are essentially non-toxic, and, therefore, clay mineral-biocompatible polymer nanocomposites are a logical research direction. The field was nicely reviewed by Wu et al. (2011). Several categories of biomaterials may benefit from the development of CPN. Some polymers such as PNIPAM form hydrogels, that is, they can retain many times their own mass of water (up to several hundred times). These hydrogels may be used for water adsorption (disposable diapers, water reserves in soils, fire-extinguishing gels) and are also called super-adsorbents. They can also be used as scaffolds in tissue engineering (wound healing, tissue regeneration), as cell culture matrixes, and for drug delivery (Peppas et al., 2000; Oh et al., 2008). Conventional hydrogels with purely organic cross-linked polymers are usually weak and brittle. In contrast, the laponite–PNIPAM nanocomposite hydrogels, first developed by Haraguchi and Takehisa (2002), exhibit an extraordinary resistance to elongation and deformation due to the cooperative behaviour of the organic and inorganic components of the matrix (Fig. 13.1.2). Haraguchi et al. (2006) studied cell cultivation and cell sheet detachment on hydrogel surfaces. Cell adhesion needs to be controlled for many biotechnological applications involving the cultivation of microorganisms. Thus, to promote osteo-integration, it is desirable to obtain materials with properties as close as possible to the bone matrix, and this refers not only to the macroscopic behaviour such as mechanical properties (Ozkoc et al., 2010), but also to the molecular-level affinity for efficient interaction with the cell. The reason for this affinity is not perfectly understood and is the subject of active research. In practice, interesting results have been obtained; for example, enhanced cell adhesion and proliferation were observed on Mt–chitosan–gelatin nanocomposite films as compared with the pristine polymers (Zhuang et al., 2007).

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A different type of biomaterials is used for implants such as cardiac pacemakers. They are sealed devices containing electronic components that would be corroded by direct contact with body fluids. Barrier properties are obviously important in this case, and the interest in improving the barrier properties of CPN has already been mentioned. Thus, the addition of cloisite to medical-grade PU resulted in a fivefold decrease in water permeability (Xu et al., 2001, 2003). Drug delivery, or controlled drug release, is another domain of intensive research in biotechnology. CPN would seem attractive for this kind of application since both clay minerals (Aguzzi et al., 2007) and polymers are separately used with much success. It is expected that many related studies on various CPN systems will be published in the future. Chitosan–Mt nanocomposites are particularly promising candidates for modified drug delivery formulations (Salcedo et al., 2012). There is a large potential to develop ‘smart’ systems that react to a precise trigger: to release the drug component only at a specific location and/or at a specific time. Since hydrogels react to several triggers, research is going on for clay mineral–hydrogel nanocomposites. Thus, in a layer-by-layer Mt–PNIPAM, swelling properties were shown to be highly dependent on both pH and temperature (Zhuk et al., 2011). Biosensors are devices that make use of the change in material properties upon interaction with a given molecule in order to detect it selectively. They have great potential, for example, for implanted diagnostic devices. Chitosan– Mt nanocomposites have been used to manufacture electrodes for potentiometric sensors (Darder et al., 2003).

13.1.1.7 Clay Mineral–Polymers and Optical Properties Controlled optical properties are required for some polymer applications. For instance, PC is used for the production of CD, DVD and Blu-Ray disks; in addition to good mechanical properties such as scratch resistance, transparency is demanded. The refractive index is also a key optical property. The optical properties (colour formation) of clay mineral–PC nanocomposites have been reported (Huang et al., 2000; Yoon et al., 2003a,b). Biodegradable polyester nanocomposites, organoclays–PLLA, showed a good optical clarity due to their nanometre-range dispersion (Krikorian and Pochan, 2003). This also holds for Mt–PP nanocomposites, which, in addition, exhibit better scratch resistance (Manias et al., 2001). More sophisticated tailoring of optical properties by controlling material structuration in the nanometric range is a real perspective, especially for clay mineral–BCP nanocomposites (Bockstaller et al., 2005). Worth mentioning is the preparation of liquid-crystal composites with memory effects. At a content of about 2%, organoclays form CPN of the intercalated type with some liquid crystals, and these CPN could be switched by an electric field from an opaque to a transparent state (Kawasumi et al., 1996).

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13.1.1.8 Clay Mineral–Polymers for Electrical Properties: Ionic Conductivity and Fuel Cells Classically, some CPN have been used as cable insulators (Bergaya and Lagaly, 2007), an application where not only flame retardancy but also low electric conductivity is needed. Moreover, since the clay mineral particles contain exchangeable ions, CPN are likely candidates for ionic conduction, especially when the clay minerals are exchanged by small cations such as Liþ or Hþ. The first report on Liþ-Mt–PEO showed that connecting the clay mineral particles with PEO chains increased the ionic conductivity (Ruiz-Hitzky and Aranda, 1990). This is probably not surprising since pristine PEO itself can act as a matrix to dissolve lithium salts giving polymer electrolytes, which have been the subject of much interest (Fergus, 2010). Liþ-Mt–PEO remained one of the main foci of ionic conductivity studies (Sandıá et al., 2003). In one of the few mechanistic studies, Reinholdt et al. (2005) studied the mechanisms responsible for Naþ and Liþ ion migration in Mt–PEO nanocomposites at the molecular level. Conflicting results have been obtained in this field because systems with very different compositions were investigated. Fluorohectorite (Mehrotra and Giannelis, 1992) was exposed to pyrrole vapour, yielding a fluorohectorite– PPy nanocomposite that contained 84 mass% of hectorite. After I2 doping, room temperature (RT) conductivities sdc of 105 to about 102 S/cm were measured, and they were pronouncedly anisotropic (4000 times less in the direction perpendicular to the clay mineral layers). In contrast, Liþ-Mt– PPy with only 15% Mt showed RT conductivities of 6 S/cm (Kim and Park, 2007), and the conductivity sdc followed a temperature dependence compatible with a three-dimensional hopping model. The same authors had previously studied a Mt–PANI nanocomposite of a similar composition. In this case, the temperature dependence was compatible with a onedimensional hopping model (Kim et al., 2002) and the RT conductivity was on the order of 1 S/cm, somewhat lower than that of the pristine polymer. Even though rubber is a good insulator, rubber-based materials were prepared with conductivities in the semiconductor range by the addition of minor amounts of clay minerals in Mt–NR–PPy nanocomposites (Pojanavaraphan and Magaraphan, 2010). A review of studies involving PANI, PTh and PPy polymers can be found in Aranda et al. (2006). Alternatively to alkali ion conductivity, some polymer electrolytes rely on proton conduction, which was also studied with CPN. For instance, studies were devoted to Mt–sPEEK (Chang et al., 2003c; Hasani-Sadrabadi et al., 2008), laponite–sPEEK (Chang et al., 2003c) and Liþ-Mt–Nafion (Alonso et al., 2009). The applications envisaged in these studies chiefly concern Liþ and Naþ fuel cells and membranes. Vaia et al. (1995) were probably the first authors to test CPN systems as electrolytes for polymer-based batteries in real conditions.

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The ‘clay–caramel’ nanocomposites prepared by thermal activation of sucrose in the presence of Mt (Darder and Ruiz-Hitzky, 2005) have already been mentioned. In fact, heating at higher temperatures transformed them to Mt–carbon nanocomposites with good electrical conductivity (in the range of semiconductors).

13.1.2 CPN PREPARATION METHODS The dispersion of a clay mineral into a polymer matrix, like any chemical reaction, will be possible only if it corresponds to a decrease in free enthalpy. The entropy change is unfavourable (i.e. entropy decrease) because the polymer chains lose configurational entropy if they are partly confined between the clay mineral layers. To overcome this effect, the enthalpic effect must be favourable; that is, the interaction between the polymer and the clay mineral layers must be exothermic. These basic considerations were put on a more quantitative basis by Vaia and Giannelis (1999a,b) who estimated the entropy changes based on a lattice model of polymer chains. In the following section, CPN preparation methods are classified on the basis of the strategy used to make the clay mineral–polymer interaction favourable.

13.1.2.1 Direct Polymer Intercalation in Clay Minerals (Solid-State Compounding or Solvent Casting) The surfaces of pristine clay minerals are hydrophilic because of the existence of more or less localized layer charges and adsorbed water molecules. Clay mineral nanocomposites with hydrophilic, water-soluble biopolymers such as pectin can be obtained from aqueous dispersions or, even better, by direct solid-state ball milling (Mangiacapra et al., 2006). In other cases, the polymer could be directly intercalated into a pristine clay mineral by using a nonaqueous solvent, for example, N,N-dimethyl acetamide in the case of Mt–sPEEK nanocomposites (Hasani-Sadrabadi et al., 2008).

13.1.2.2 Methods Based on Adjusting the Hydrophilic–Lipophilic Balance Many of the polymers of interest in CPN, especially in the field of elastomers, are hydrophobic. They have very little tendency to interact with clay mineral surfaces and there is no driving force for clay mineral dispersion. This can be expressed by the hydrophilic–lipophilic balance (HLB). A molecule, or a surface, has a hydrophilic (water-loving) character if it interacts favourably with water, and a lipophilic (literally, fat-loving) character if it interacts favourably with apolar solvents. The two notions are often represented as the opposite ends of a continuum (although this is certainly an oversimplification). To disperse clay mineral particles into a polymer matrix, the HLB of the two components must be similar.

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13.1.2.2.1 Polymer Intercalation in Organoclays Directly modifying the chemical nature of the layers is a rarely used strategy, although it was reported that partial fluorination (fluoride ions substituting OH groups of the layers) made the clay mineral more lipophilic and allowed PP intercalation (Manias et al., 2001). A much more common strategy is to use organoclays. The vast literature on organoclays cannot be reviewed here; the reader is referred to Chapter 10.3 and to a recent review (Bergaya et al., 2011). According to De Paiva et al. (2008), more than half of the research articles published on organoclays in the past decade dealt with the preparation of CPN. Pronounced interaction between both components of the nanocomposite (organoclays and apolar polymer) make possible ‘green’, that is, solvent-less, methods such as melt intercalation or extrusion. Melt-processing was proposed for Mt–PEO (Vaia et al., 1995) and various organoclay/non-polar polymers (Giannelis, 1996). It involves heating a mixture of the two components in the solid state above the softening point of the polymer (for more technical details on CPN casting procedures, see Tjong, 2006). Alternatively, solvent casting may be used, where both components are dispersed into a mutually compatible solvent, such as toluene for non-polar polymers and organoclays.

13.1.2.2.2 Polymer Modification by the use of Compatibilizers The ‘organoclay strategy’ consists in making the clay mineral compatible with the polymer. The opposite approach can also be adopted, that is, making the polymer compatible with the clay mineral. In this case, hydrophilic groups can be grafted on the polymer chains. Thus, polar moieties such as maleic anhydride, acryclic acid or linear alcoholic chains were introduced into PS (Manias et al., 2001), which allowed the preparation of the corresponding CPN by melt processing. Maleic anhydride is indeed a particularly well-suited compatibilizer which was used to modify a number of apolar polymers (Ganguly and Bhowmick, 2009) or even polar ones such as cellulose acetate (Park et al., 2004). It may be more efficient to introduce ionisable groups into the polymer chains, which can be protonated and then ion-exchanged within the clay mineral, for example, PS-NHþ 3 (Hoffmann et al., 2000). In this case, the polymer chains will preferentially interact with the nanofiller than with each other, thus providing the ‘enthalpic engine’ that enables intercalation. Compatibilisers may rely on thermodynamic driving forces that are not well rationalized by the hydrophilic/lipophilic paradigm. Maleic anhydride groups grafted on the polymer were reported to form covalent bonds with alcohol functionality on the ethyl chains of the surfactants in the organoclay (Park et al., 2004; Di Gianni et al., 2009). This implies a modification of both the polymer and the organoclay components. It should be noted that some commercially available organoclays, such as cloisite (marketed by Southern

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Clays Inc., Wyoming), contain surfactants with a significant amount of hydroxylated groups (methyltallow bis(2-hydroxyethyl) ammonium).

13.1.2.2.3 ‘One-pot’ Synthesis While organoclays are commercially available, the commercial products are not necessarily fine-tuned to the required CPN synthesis procedure, and industrialists may want to synthesise them de novo. In such a case, one-pot synthesis is a viable alternative. In this approach, the three components of the CPN, namely, the clay mineral, the surfactant, and the polymer, are added together in a single operation. This approach was used, for instance, to prepare CPN with NR (Galimberti et al., 2007), PE (Bergaya, 2004; Bergaya et al., 2005), or EVA (Alexandre et al., 2001; Tian et al., 2004). In the latter case, no significant differences were observed from a nanocomposite prepared using a previously synthesised organoclay.

13.1.2.3 In Situ Polymerization As already stated, it may require special molecular modifications (and therefore additional elementary operations) to force pre-existing polymer chains to enter the interlayer space of clay minerals. As mentioned earlier, the first CPN were obtained by in situ polymerization of monomers previously intercalated in the interlayer space. One of the first studies conducted with this purpose concerned Mt–PAN nanocomposites (Bergaya and Kooli, 1991). OrganoMt–PLA (Silvino et al., 2012), Mt–PCL (Lepoittevin et al., 2002; Kiersnowski et al., 2004), and clay mineral–polylactone nanocomposites are often prepared in this way. In the case of polylactones, ring-opening polymerization is involved. Other systems are clay mineral–PU, clay mineral–PC, clay mineral–PS (Han et al., 2003), and several clay mineral–copolymers (Di and Sogah, 2006). Polymerization may occur at the gas interface, in the melt, in dispersions or in emulsions (Lee and Jang, 1996; Huang and Brittain, 2001; Wang et al., 2002). Of advantage may be the co-adsorption of an initiator or a polymerization catalyst, or photopolymerization (Decker et al., 2005; Owusu-Adom and Guymon, 2008).

13.1.2.4 Polymer-Templated Clay Mineral Synthesis One can also start from small inorganic clay mineral precursors to which the desired polymer (normally hydrophilic) is added. In this way, polymer-containing silicate gels were hydrothermally crystallised to form hectorite–polymer nanocomposites (Carrado and Xu, 1998). The different methods of preparation of CPN, which are summarised in Fig. 13.1.2, lead to intimate interactions between the polymer and the clay mineral, yielding intercalated or exfoliated nanocomposites.

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C

F

+ + FIGURE 13.1.2 Different strategies for CPN synthesis. Rectangles, clay layers; wobbly lines, non-polar polymer chains; small open circles, polar groups. (A) direct intercalation of hydrophilic polymers into pristine clay mineral, (B) intercalation of apolar polymers into organoclays (clays pre-expanded by surfactants such as alkylammoniums), (C) pre-compatibilisation of polymer through grafting of polar moieties for intercalation into pristine clay minerals, (D) one-pot synthesis. (E) in situ polymerisation, (F) polymer-templated clay mineral synthesis.

13.1.3 INTERACTION MECHANISMS AND STRUCTURE CHARACTERIZATION 13.1.3.1 Intercalated versus Exfoliated Nanocomposites Some of the first reports on CPN considered clay minerals as cross-linkers between polymer chains. A breakthrough came when the nanometric character of these materials was actually recognized (Fig. 13.0.1). Some doubt exists as to whether CPN with fully exfoliated clay mineral particles really exist. Isolated clay mineral layers often shown in electron micrographs may not be representative because of a more or less conscious selection bias. Schaefer and Justice (2007) underlined the fact that ‘cartoon’ representations of composite materials can be misleading. They represent oversimplifications of a more complex reality because they picture clay mineral layers (and polymer chains) as featureless macroscopic objects without providing any molecular detail.

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Broken edges

FIGURE 13.1.3 ‘Plugging’ of an unfolded polypeptide fragment at the broken edges of Mt particles, with side chains pointing into the interlayer spaces. From Gougeon et al. (2003), with permission.

In the ‘plugging’ model derived from an in-depth study of polylysine (and polyglutamic acid) interaction with Mt (Gougeon et al., 2002, 2003, 2006), it was assumed that the polypeptide backbones do not enter the interlayer space, while their side chains are adsorbed at the periphery of the clay mineral particles (Fig. 13.1.3).

13.1.3.2 Diversity of Smectites Industrialists as well as polymer scientists prefer to use for reinforcement purposes materials that are already being marketed in large amounts (clays, clay minerals, or organoclays such as cloisite). The unfortunate result is that little attention is paid to the precise nature of the clay mineral component and, as pointed out by Bergaya and Lagaly (2007), little use is made of the structural diversity of smectites as potential fillers. These authors discussed the potential use of synthetic clay minerals at least as reference points in CPN studies, underlining that Mt, the main component of the most commonly used clay mineral fillers, is not easily synthesised. Among the few studies that did compare different clay mineral fillers, the work of Kornmann et al. (2001) considered the effect of the CEC of Mt in organo-Mt–epoxy nanocomposites. They obtained intercalated CPN with smaller interlayer distances when the CEC of the Mt was larger. In organoclays, an additional source of variation is the chemical nature of the intercalated surfactant. Yoon et al. (2003b) showed that organo-Mt–PC nanocomposites with a surfactant having both poly(oxoethylene) and octadecyl tails led to the best structural properties and modulus improvement of the CPN. These results reveal interesting information on the driving force for the organoclay–polymer interaction. In a similar study on organo-Mt–PS and organo-Mt–PMMA nanocomposites, Wang et al. (2002) concluded that exfoliation was more likely if the surfactant chains contained a double bond, which could probably participate in the polymerization reaction and anchor the chain to the clay mineral layers. Stretz et al. (2005) studied the effect of surfactant chain length, and showed a better dispersion of clay mineral particles when shorter chain surfactants were used.

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Chang et al. (2003b) compared Naþ-Mt and Naþ-saponite and two organoclays as fillers for the preparation of clay mineral–PVA nanocomposites and concluded that the optimal filler depended on the property considered. Other clay minerals such as vermiculite with PP (Tjong et al., 2002) or with PLLA, PMMA, PEO (Auliawan and Woo, 2011), synthetic mica with PLA (Chang et al., 2003a), and rectorite with guar gum (Wang and Wang, 2009) were also investigated as fillers for CPN. A comparison of these materials with smectite fillers would help in establishing the role of such parameters as layer charge (for vermiculite and mica) and layer rigidity (for rectorite).

13.1.3.3 Characterization Techniques 13.1.3.3.1 Structural Information by Transmission and Scanning Electron Microscopy and by X-ray Diffraction Depending on whether one observes the d001 value of the pristine clay mineral or organoclay, a higher value or no reflections at all, the CPN will be assigned to the micrometric, intercalated or exfoliated class. However, exfoliation is not considered to be successfully demonstrated without the real-space information that is provided by transmission electron microscopy (TEM) (Eckel et al., 2004). That is why these two techniques must be systematically applied to CPN characterization, especially in the field of elastomers (Galimberti, 2011). Electron microscopy sometimes reveals other details of the organization of CPN. For instance, in a nanocomposite containing segmented PU together with laponite and cloisite, laponite was observed to bind preferentially with the hard segments and cloisite with the soft ones (Mishra et al., 2008). Scanning electron microscopy is used occasionally to obtain technical information such as the aspect of composite surfaces after fracture. The necessity of multi-scale characterization of CPN organization has been outlined several times and, as for other polymer science questions, addressed by a combination of X-ray (WAXS and SAXS including USAXS) techniques (Bafna et al., 2003), or by a combination of XRD, TEM and atomic force microscopy (AFM) (Marras et al., 2007). Park et al. (2004) revealed the coexistence of intercalated and exfoliated structures or of intercalated structures and micrometric aggregates in the same samples by using AFM. Rheology is of course often applied to control the polymer processing procedures, and was in particular advocated as a tool to assess the degree of clay mineral dispersion, complementary to other structural CPN characterization techniques (Zhao et al., 2005). 13.1.3.3.2 Molecular-Level Information by Vibrational Spectroscopies As already underlined, the interaction between the polymer and the clay mineral layers must be exothermic in order to obtain a good dispersion.

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To understand this interaction, any technique able to observe at the molecular level the modifications of either the clay mineral and/or the polymer component will be useful. This chiefly includes the usual spectroscopic methods of organic and inorganic chemistry. Vibrational spectroscopies, including IR, are of course good candidates for this purpose. IR spectra allow (i) following the course of in situ polymerization (Faguy et al., 1995), sometimes significantly different from free polymerization (Do Nascimento and Temperini, 2008), or (ii) identifying the bands of the polymer and those of the clay mineral in the final CPN (Depan et al., 2009) to evidence specific interactions. Thus, in a 2% cloisite–HDPE nanocomposite, the clay mineral band envelope, containing several bands of the inorganic matrix in the 950–1200 cm1 region, was carefully analysed, and, in particular, the out-of-plane SidO bending mode showed a coherent evolution during polymer processing. This was attributed to the onset of the clay mineral/polymer interaction but it remained unclear what type of interaction was involved (Cole, 2008). Changes in the SidO bands upon CPN formation were also reported by Sikdar et al. (2008). In PVOH–starch, when the clay mineral was added, shifts of the polymer bands, especially of the OH stretching bands, were observed (Dean et al., 2008). Shifts of the CH3 deformation bands were related to H-bond interactions in organo-Mt–PP nanocomposites, but were absent in organo-Mt–PE (Deshmane et al., 2007). H-bonding was also reported for Mt–caprolactam (Katti et al., 2006). In general, one expects changes in the IR bands of the polymer, which, however, are more difficult to detect than those of the clay mineral because the clay mineral particles are present in relatively small amounts and not all polymer moieties can directly interact with the particles. Reported band shifts for both components were rather small and difficult to interpret. The most convincing conclusions may have been based on the absence of significant IR band shifts, which, in some cases, were used to preclude covalent bonds (grafting) (Lee and Jang, 1996). Finally, IR may reveal the presence of non-intercalated crystalline surfactants (Deng et al., 2006), which were reported to be detrimental to the properties of the CPN.

13.1.3.3.3 Molecular-Level Information by Solid-State Nuclear Magnetic Resonance The general interest in nuclear magnetic resonance (NMR) techniques for organic/inorganic multicomponent materials was reviewed by Geppi et al. (2009). Grandjean (2006) reported a solid-state NMR study more focused on CPN and organoclays. Clay minerals contain ‘good’ NMR nuclei, namely, 29Si and 27Al. 29Si is little affected by the formation of the CPN with respect to the pristine clay

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mineral. 27Al is a quadrupolar nucleus and, in addition to the chemical shift, the NMR signal reveals the QCC (quadrupole coupling constant), which allows more precise site identification. The polymer has at least two nuclei that are NMR-active, 13C and 1H. Small changes in the 13C spectra of polymer chains were observed in Mt–starch (Chen and Evans, 2005) and Mt–PCL (Chen and Evans, 2006) as compared to the pristine polymers. 13C spectra were also recorded for caramel–clay mineral nanocomposites (Darder and Ruiz-Hitzky, 2005). 1 H NMR was used to assess the degree of polymerization of caprolactone (Messersmith and Giannelis, 1995; Kiersnowski et al., 2004). Vanderhart et al. (2001a,b) showed by 1H and 13C NMR a stabilization of g over a crystallites in nylon–Mt due to the presence of the clay mineral. Similar conclusions were drawn from 15N NMR (Mathias et al., 1999). Other informative nuclei are available only in special categories of nanocomposites. For instance, Zhang et al. (2007), using 19F spectra of organoMt/Nafion, revealed that some functional groups of the polymer chain had a restricted mobility, indicating that they preferentially interacted with the clay mineral particles. Reinholdt et al. (2005) used 7Li and 23Na (naturally present in the interlayer cations) to characterize the interlayer hydration in Mt–PEO nanocomposites and concluded that the interlayer cations were not complexed by the polymer chains. HETCOR (HETero-nuclear CORrelation) allows the estimation of distances between two NMR-active nuclei. In hectorite/block PS-PEO, Hou et al. (2002, 2003) identified by 1H-29Si HETCOR the enrichment of PEO protons in close vicinity to the Si atoms of clay mineral particles, and hypothesized that they corresponded to intercalated PEO segments, while the PS units were not intercalated, as expected considering the polarity of the two types of segments. An additional technique, WISE (WIdeline SEparation), which is sensitive to the mobility of molecular groups (Schmidt-Rohr et al., 1992), confirmed that the mobility of the PEO chains was indeed reduced. 1H-27Al HETCOR was also used to study Mt–polypeptide nanocomposites and provided the basis to develop the ‘plugging’ model shown in Fig. 13.1.3 (Gougeon et al., 2002, 2003, 2006). The measurement of relaxation times T1, T2 and T1r of 1H or 13C (see Geppi et al., 2009 for an introduction) is a well-established but non-trivial way to quantitatively evaluate the state of motion of molecular groups. Such measurements were applied to problems involving the mobility or rigidity of polymer chains and chain segments (Forte et al., 1998; Vanderhart et al., 2001a; Bourbigot et al., 2003, 2004; Kuo et al., 2003; Urbanczyk et al., 2006). In a multi-technique NMR study, Brus et al. (2006) characterized both the structure and the dynamics of the polymer chains of Mt–nylon nanocomposites. Such studies of chain mobility represent the most commonly used NMR technique for CPN, while some other methods are still at the stage of proving the concept.

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13.1.3.3.4 Molecular Modelling In many problems of materials science, especially where matter is not periodically arranged and therefore diffraction techniques are not available, molecular modelling has become an important tool, as the energetically optimized molecular configurations can be used to choose between otherwise ambiguous molecular interpretations of data. For CPN, however, the task is daunting because of the necessity to integrate very different space and time scales (Fermeglia et al., 2009). Since any realistic simulation requires a very large number of atoms, high-level methods cannot be applied to the complete system, so currently the only envisageable approach is that of molecular mechanics (MM), especially coarse-grained methods (Sinsawat et al., 2003). MM was used to investigate clay mineral/surfactant and clay mineral/polymer (polyamide) interactions of CPN (Katti et al., 2006; Sikdar et al., 2010). In another study, a methodology was developed to integrate the results of molecular-level modelling with a mesoscopic simulation technique, namely, dissipative particle dynamics (Scocchi et al., 2007). These studies, although interesting, are still in the exploratory stage.

13.1.4 CONCLUSION Smectite–polymer nanocomposites constitute a vast domain where success stories in the realm of structural materials or elastomers coexist with burgeoning fields. Overall, the picture is that of an explosive development in many directions. The large number of possible polymers, possible synthetic methods and possible technological applications, together with the strong incentive to enhance polymer properties, guarantee that the activity in this domain will keep growing. We are dealing with a (nano)technology that is in its booming stage but many fascinating avenues remain unexplored. In a field so much driven by the hope of immediate valorisation, fundamental understanding is lagging behind, and theoretical models often remain simplistic, especially regarding molecular-scale phenomena. Thus, there is room for much deeper spectroscopic characterization of the interaction between the different components of CPN, and also for a more targeted use of the different properties of the various smectites and also of other clay minerals.

REFERENCES Aguzzi, C., Cerezo, P., Viseras, C., Caramella, C., 2007. Use of clays as drug delivery systems: possibilities and limitations. Appl. Clay Sci. 36, 22–36. Alexandre, M., Dubois, P., 2000. Polymer-layered silicate nanocomposites: preparation, properties and uses of a new class of materials. Mater. Sci. Eng. 28, 1–63. Alexandre, M., Beyer, G., Henrist, C., Cloots, R., Rulmont, A., Jerome, R., Dubois, P., 2001. Onepot preparation of polymer/clay nanocomposites starting from Naþ montmorillonite. 1. Melt intercalation of ethylene-vinyl acetate copolymer. Chem. Mater. 13, 3830.

698


Alonso, R.H., Estevez, L., Lian, H., Kelarakis, A., Giannelis, E.P., 2009. Nafion–clay nanocomposite membranes: morphology and properties. Polymer 50, 2402–2410. Aranda, P., Darder, M., Fernańdez-Saavedra, R., Lo´pez-Blanco, M., Ruiz-Hitzky, E., 2006. Relevance of polymer– and biopolymer–clay nanocomposites in electrochemical and electroanalytical applications. Thin Solid Films 495, 104–112. Arora, A., Padua, G.W., 2010. Review: nanocomposites in food packaging. J. Food Sci. 75, R43–R49. Arroyo, M., Lopez-Manchado, M.A., Herrero, B., 2003. Organo-montmorillonite as substitute of carbon black in natural rubber compounds. Polymer 44, 2447–2453. Auliawan, A., Woo, E.M., 2011. Nanocomposites based on vermiculite clay and ternary blend of poly(L-lactic acid), poly(methyl methacrylate), and poly(ethylene oxide). Polym. Compos. 32, 1916–1926. Ave´rous, L., Pollet, E. (Eds.), 2012. Environmental Silicate Nano-biocomposites. Springer Verlag, London. Bafna, A., Beaucage, G., Mirabella, F., Mehta, S., 2003. 3D hierarchical orientation in polymerclay nanocomposite films. Polymer 44, 1103–1115. Bergaya, F., 2004. Clay polymer nanocomposite. In: Yamagishi, A., Sato, H. (Eds.), Proceeding of Tokyo Conference on Nanostructured Materials Based on Layered Inorganics. Tokyo, Japan, pp. L-9.1–L-9.3. Bergaya, F., Kooli, F., 1991. Acrylonitrile-smectite complexes. Clay Miner. 26, 33–41. Bergaya, F., Lagaly, G., 2007. Clay mineral properties responsible for clay-based nanocomposite (CPN) performance. In: Carrado, K.A., Bergaya, F. (Eds.), CMS Workshop Lectures, vol. 15. The Clay Minerals Society, Chantilly, VA, pp. 61–96. Bergaya, F., Mandalia, T., Amigoue¨t, P., 2005. Nanocomposite based on PE and novel modified raw clays. Colloid Polym. Sci. 283, 773–782. Bergaya, F., Jaber, M., Lambert, J.-F., 2011. Organophilic clay minerals. In: Galimberti, M. (Ed.), Rubber Clay Nanocomposites. Science, Technology and Application. J. Wiley & Sons, Chichester. Chapter 2. Bhat, S.D., Aminabhavi, T.M., 2006. Novel sodium alginate-NaþMMT hybrid composite membranes for pervaporation dehydration of isopropanol, 1,4-dioxane and tetrahydrofuran. Sep. Purif. Technol. 51, 85–94. Biswas, M., Sinha Ray, S., 2001. Recent progress in synthesis and evaluation of polymer—montmorillonite nanocomposites. Adv. Polym. Sci. 135, 167–221. Bitinis, N., Hernandez, M., Verdejo, R., Kenny, J.M., Lopez-Manchado, M.A., 2011. Recent advances in clay/polymer nanocomposites. Adv. Mater. 23, 5229–5236. Blumstein, A., 1961. Etude des Polyme´risations en Couche Adsorbeé. 1. Bull. Soc. Chim. Fr. 5, 899–906. Blumstein, A., 1965. Polymerization of adsorbed monolayers. I. Preparation of clay-polymer complex. J. Polym. Sci. A 3, 2653–2664. Bockstaller, M.R., Mickiewicz, R.A., Thomas, E.L., 2005. Block copolymer nanocomposites: perspectives for tailored functional materials. Adv. Mater. 17, 1331–1349. Bordes, P., Pollet, E., Ave´rous, L., 2009. Nano-biocomposites: biodegradable polyester/nanoclay systems. Prog. Polym. Sci. 34, 125–155. Bourbigot, S., Vanderhart, D.L., Gilman, J.W., Awad, W.H., Davis, R.D., Morgan, A.B., Wilkie, C.A., 2003. Investigation of nanodispersion in polystyrene montmorillonite nanocomposites by solid-state NMR. J. Polym. Sci. B 41, 3188–3213. Bourbigot, S., Vanderhart, D.L., Gilman, J.W., Bellayer, S., Stretz, H., Paul, D.R., 2004. Solid state NMR characterization and flammability of styrene acrylonitrile copolymer montmorillonite nanocomposite. Polymer 45, 7627–7638.

Chapter

13.1


699

Brus, J., Urbanova, M., Kelnar, I., Kotek, J., 2006. A solid-state NMR study of structure and segmental dynamics of semicrystalline elastomer-toughened nanocomposites. Macromolecules 39, 5400–5409. Capadona, J.R., Van Den Berg, O., Capadona, L.A., Schroeter, M., Rowan, S.J., Tyler, D.J., Wede, C., 2007. A versatile approach for the processing of polymer nanocomposites with self-assembled nanofibre templates. Nat. Nanotechnol. 2, 765–769. Carrado, K.A., 2000. Synthetic organo- and polymer-clays: preparation, characterization, and materials applications. Appl. Clay Sci. 17, 1–23. Carrado, K.A., Xu, L.Q., 1998. In situ synthesis of polymer-clay nanocomposites from silicate gels. Chem. Mater. 10, 1440–1445. Chang, J.H., An, Y.U., Cho, D.H., Giannelis, E.P., 2003a. Poly(lactic acid) nanocomposites: comparison of their properties with montmorillonite and synthetic mica(II). Polymer 44, 3715–3720. Chang, J.H., Jang, T.G., Ihn, K.J., Lee, W.K., Sur, G.S., 2003b. Poly(vinyl alcohol) nanocomposites with different clays: pristine clays and organoclays. J. Appl. Polym. Sci. 90, 3208–3214. Chang, J.H., Park, J.H., Park, G.G., Kim, C.S., Park, O.O., 2003c. Proton-conducting composite membranes derived from sulfonated hydrocarbon and inorganic materials. J. Power Sour. 124, 18–25. Chen, B.Q., Evans, J.R.G., 2005. Thermoplastic starch-clay nanocomposites and their characteristics. Carbohydr. Polym. 61, 455–463. Chen, B.Q., Evans, J.R.G., 2006. Poly(epsilon-caprolactone)-clay nanocomposites: structure and mechanical properties. Macromolecules 39, 747–754. Chen, B., Evans, J.R.G., Greenwell, H.C., Boulet, P., Coveney, P.V., Bowden, A.A., Whiting, A., 2008. A critical appraisal of polymer-clay nanocomposites. Chem. Soc. Rev. 37, 568–594. Choudalakis, G., Gotsis, A.D., 2009. Permeability of polymer/clay nanocomposites: a review. Eur. Polym. J. 45, 969–984. Choy, J.-H., Choi, S.-J., Oh, J.-M., Park, T., 2007. Clay minerals and layered double hydroxides for novel biological applications. Appl. Clay Sci. 26, 122–132. Cole, K.C., 2008. Use of infrared spectroscopy to characterize clay intercalation and exfoliation in polymer nanocomposites. Macromolecules 41, 834–843. Dang, Q., Lu, S., Yu, S., Sun, P., Yuan, Z., 2010. Silk fibroin/montmorillonite nanocomposites: effect of pH on the conformational transition and clay dispersion. Biomacromolecules 11, 1796–1801. Darder, M., Ruiz-Hitzky, E.R., 2005. Caramel-clay nanocomposites. J. Mater. Chem. 15, 3913–3918. Darder, M., Colilla, M., Ruiz-Hitzky, E., 2003. Biopolymer-clay nanocomposites based on chitosan intercalated in montmorillonite. Chem. Mater. 15, 3774–3780. Darder, M., Ruiz, A.I., Aranda, P., Van Damme, H., Ruiz-Hitzky, E., 2006. Bio-nanohybrids based on layered inorganic solids: gelatin nanocomposites. Curr. Nanosci. 2, 231–241. Darder, M., Aranda, P., Ruiz-Hitzky, E., 2007. Bionanocomposites: a new concept of ecological, bioinspired, and functional hybrid materials. Adv. Mater. 19, 1309–1319. De Azeredo, H.M.C., 2009. Nanocomposites for food packaging applications. Food Res. Int. 42, 1240–1253. De Paiva, L.B., Morales, A.R., Valenzuela Diaz, F.R., 2008. Organoclays: properties, preparation and applications. Appl. Clay Sci. 42, 8–24. Dean, K.M., Do, M.D., Petinakis, E., Yu, L., 2008. Key interactions in biodegradable thermoplastic starch/poly(vinyl alcohol)/montmorillonite micro- and nanocomposites. Compos. Sci. Technol. 68, 1453–1462.

700


Decker, C., Keller, L., Zahouily, K., Benfarhi, S., 2005. Synthesis of nanocomposite polymers by UV-radiation curing. Polymer 46, 6640–6648. Deng, Y.J., Dixon, J.B., White, G.N., 2006. Bonding mechanisms and conformation of poly(ethylene oxide)-based surfactants in interlayer of smectite. Colloid Polym. Sci. 284, 347–356. Depan, D., Kumar, A.P., Singh, R.P., 2009. Cell proliferation and controlled drug release studies of nanohybrids based on chitosan-g-lactic acid and montmorillonite. Acta Biomater. 5, 93–100. Deshmane, C., Yuan, Q., Perkins, R.S., Misra, R.D.K., 2007. On striking variation in impact toughness of polyethylene–clay and polypropylene–clay nanocomposite systems: the effect of clay–polymer interaction. Mater. Sci. Eng. A 458, 150–157. Di Gianni, A., Colucci, G., Priola, A., Conzatti, L., Alessi, M., Stagnaro, P., 2009. Exfoliated/ intercalated rubber/organo-montmorillonite nanocomposites: preparation and characterization. Macromol. Mater. Eng. 294, 705–710. Di, J., Sogah, D.Y., 2006. Exfoliated block copolymer/silicate nanocomposites by one-pot, onestep in-situ living polymerization from silicate-anchored multifunctional initiator. Macromolecules 39, 5052–5057. Do Nascimento, G.M., Temperini, M.L.A., 2008. Structure of polyaniline formed in different inorganic porous materials: a spectroscopic study. Eur. Polym. J. 44, 3501–3511. Eckel, D.F., Balogh, M.P., Fasulo, P.D., Rodgers, W.R., 2004. Assessing organoclay dispersion in polymer nanocomposites. J. Appl. Polym. Sci. 93, 1110–1117. Faguy, P.W., Lucas, R.A., Ma, W., 1995. An Ft-Ir-Atr Spectroscopic study of the spontaneous polymerization of pyrrole in iron-exchanged montmorillonite. Colloids Surf. A 105, 105–112. Fergus, J.W., 2010. Ceramic and polymeric solid electrolytes for lithium-ion batteries. J. Power Sour. 195, 4554–4569. Fermeglia, M., Maly, M., Posocco, P., Pricl, S., 2009. Multiscale molecular modeling of hybrid organic–inorganic nanocomposites of type I and II. In: Vincenzini, P., d’Arrigo, G. (Eds.), Smart Materials and Micro/Nanosystems. Advanced Science Technology, Vol. 54. Trans Tech Publications, Stafa, Zu¨rich, pp. 265–269. Forte, C., Geppi, M., Giamberini, S., Ruggeri, G., Veracini, C.A., Mendez, B., 1998. Structure determination of clay methyl methacrylate copolymer interlayer complexes by means of 13 C solid state NMR. Polymer 39, 2651–2656. Franchi, M., Bramanti, E., Bonzi, L.M., Orioli, P.L., Vettori, C., Gallori, E., 1999. Clay-nucleic acid complexes: characteristics and implications for the preservation of genetic material in primeval habitats. Orig. Life Evol. Biosph. 29, 297–315. Fu, S.-Y., Feng, X.-Q., Lauke, B., Mai, Y.-W., 2008. Effects of particle size, particle/matrix interface adhesion and particle loading on mechanical properties of particulate-polymer composites. Compos. Part B 39, 933–961. Galimberti, M.E., 2011. Rubber Clay Nanocomposites. Science, Technology and Application. J. Wiley & Sons, Chichester. Galimberti, M., Lostritto, A., Spatola, A., Guerra, G., 2007. Clay delamination in hydrocarbon rubbers. Chem. Mater. 19, 2495–2499. Ganguly, A., Bhowmick, A.K., 2009. Effect of polar modification on morphology and properties of styrene-(ethylene-co-butylene)-s tyrene triblock copolymer and its montmorillonite claybased nanocomposites. J. Mater. Sci. 44, 903–918. Gawryla, M.D., van den Berg, O., Weder, C., Schiraldi, D.A., 2009. Clay aerogel/cellulose whisker nanocomposites: a nanoscale wattle and daub. J. Mater. Chem. 19, 2118–2124. Geppi, M., Borsacchi, S., Mollica, G., Veracini, C.A., 2009. Applications of solid-state NMR to the study of organic/inorganic multicomponent materials. Appl. Spectrosc. Rev. 44, 1–89.

Chapter

13.1


701

Giannelis, E.P., 1996. Polymer layered silicate nanocomposites. Adv. Mater. 8, 29–35. Giannelis, E.P., Krishnamoorti, R., Manias, E., 1999. Polymer-silicate nanocomposites: model systems for confined polymers and polymer brushes. Adv. Polym. Sci. 138, 107–147. Gilman, J.W., 1999. Flammability and thermal stability studies of polymer layered-silicate clay/ nanocomposites. Appl. Clay Sci. 15, 31–49. Gougeon, R.D., Reinholdt, M., Delmotte, L., Miehe´-Brendle´, J., Che´zeau, J.-M., Le Dred, R., Marchal, R., Jeandet, P., 2002. Direct observation of polylysine side-chain interaction with smectites interlayer surfaces through 1H- 27Al heteronuclear correlation NMR spectroscopy. Langmuir 18, 3396–3398. Gougeon, R.D., Soulard, M., Reinholdt, M., Miehe´-Brendle´, J., Che´zeau, J.-M., Le Dred, R., Marchal, R., Jeandet, P., 2003. Polypeptide adsorption on a synthetic montmorillonite: a combined solid-state NMR spectroscopy, X-ray diffraction, thermal analysis and N2 adsorption study. Eur. J. Inorg. Chem. 7, 1366–1372. Gougeon, R.D., Reinholdt, M., Delmotte, L., Miehe´-Brendle´, J., Jeandet, P., 2006. Solid-state NMR investigation on the interactions between a synthetic montmorillonite and two homopolypeptides. Solid State Nucl. Magn. Reson. 29, 322–329. Grandjean, J., 2006. Solid-state NMR study of modified clays and polymer/clay nanocomposites. Clay Miner. 41, 567–586. Han, X.M., Zeng, C.C., Lee, L.J., Koelling, K.W., Tomasko, D.L., 2003. Extrusion of polystyrene nanocomposite foams with supercritical CO2. Polym. Eng. Sci. 43, 1261–1275. Haraguchi, K., Takehisa, T., 2002. Nanocomposite hydrogels: a unique organic–inorganic network structure with extraordinary mechanical, optical, and swelling/de-swelling properties. Adv. Mater. 14, 1120–1124. Haraguchi, K., Takehisa, T., Ebato, M., 2006. Control of cell cultivation and cell sheet detachment on the surface of polymer/clay nanocomposite hydrogels. Biomacromolecules 7, 3267–3275. Hasani-Sadrabadi, M.M., Emami, S.H., Ghaffarian, R., Moaddel, H., 2008. Nanocomposite membranes made from sulfonated poly(ether ether ketone) and montmorillonite clay for fuel cell applications. Energy Fuel 22, 2539–2542. Hoffmann, B., Dietrich, C., Thomann, R., Friedrich, C., Mulhaupt, R., 2000. Morphology and rheology of polystyrene nanocomposites based upon organoclay. Macromol. Rapid Commun. 21, 57–61. Hou, S.S., Beyer, F.L., Schmidt-Rohr, K., 2002. High-sensitivity multinuclear NMR spectroscopy of a smectite clay and of clay-intercalated polymer. Solid State Nucl. Magn. Reson. 22, 110–127. Hou, S.S., Bonagamba, T.J., Beyer, F.L., Madison, P.H., Schmidt-Rohr, K., 2003. Clay intercalation of poly(styrene-ethylene oxide) block copolymers studied by two-dimensional solid-state NMR. Macromolecules 36, 2769–2776. Huang, X.Y., Brittain, W.J., 2001. Synthesis and characterization of PMMA nanocomposites by suspension and emulsion polymerization. Macromolecules 34, 3255–3260. Huang, X.Y., Lewis, S., Brittain, W.J., Vaia, R.A., 2000. Synthesis of polycarbonate-layered silicate nanocomposites via cyclic oligomers. Macromolecules 33, 2000–2004. Jaber, M., Bouchoucha, M., Delmotte, L., Me´thivier, C., Lambert, J.-F., 2011. The fate of L-DOPA in the presence of inorganic matrices—vectorization or composite material formation? J. Phys. Chem. C 115, 19216–19225. Katti, K.S., Sikdar, D., Katti, D.R., Ghosh, P., Verma, D., 2006. Molecular interactions in intercalated organically modified clay and clay-polycaprolactam nanocomposites: experiments and modeling. Polymer 47, 403–414.

702


Kawasumi, M., Usuki, A., Okada, A., Kurauchi, T., 1996. Liquid crystalline composite based on a clay mineral. Mol. Cryst. Liquid Cryst. Sci. Technol. A 281, 91–103. Kiersnowski, A., Dabrowski, P., Budde, H., Kressler, J., Piglowski, J., 2004. Synthesis and structure of poly(epsilon-caprolactone)/synthetic montmorillonite nano-intercalates. Eur. Polym. J. 40, 2591–2598. Kim, S., Park, S.-J., 2007. Preparation and ion-conducting behaviors of poly(ethylene oxide)composite electrolytes containing lithium montmorillonite. Solid State Ion. 178, 973–979. Kim, B.H., Jung, J.H., Hong, S.H., Joo, J., Epstein, A.J., Mizoguchi, K., Kim, J.W., Choi, H.J., 2002. Nanocomposite of polyaniline and Naþ-montmorillonite clay. Macromolecules 35, 1419–1423. Kojima, Y., Usuki, A., Kawasumi, M., Okada, A., Kurauchi, T., Kamigaito, O., 1993a. Synthesis of nylon-6-clay hybrid by montmorillonite intercalated with epsilon-caprolactam. J. Polym. Sci. A 31, 983–986. Kojima, Y., Usuki, A., Kawasumi, M., Okada, A., Fukushima, Y., Kurauchi, T., Kamigaito, O., 1993b. Mechanical properties of nylon 6-clay hybrid. J. Mater. Res. 8, 1185–1189. Kornmann, X., Lindberg, H., Berglund, L.A., 2001. Synthesis of epoxy–clay nanocomposites: influence of the nature of the clay on structure. Polymer 42, 1303–1310. Krikorian, V., Pochan, D.J., 2003. Poly (L-lactic acid)/layered silicate nanocomposite: fabrication, characterization, and properties. Chem. Mater. 15, 4317–4324. Kumar, A.S.K., Kalidhasan, S., Rajesh, V., Rajesh, N., 2012. Application of cellulose-clay composite biosorbent toward the effective adsorption and removal of chromium from industrial wastewater. Ind. Eng. Chem. Res. 51, 58–69. Kuo, S.W., Huang, W.J., Huang, S.B., Kao, H.C., Chang, F.C., 2003. Syntheses and characterizations of in situ blended metallocence polyethylene/clay nanocomposites. Polymer 44, 7709–7719. Lan, T., Pinnavaia, T.J., 1994. Clay-reinforced epoxy nanocomposites. Chem. Mater. 6, 2216–2219. Lan, T., Kaviratna, P.D., Pinnavaia, T.J., 1995. Mechanism of clay tactoid exfoliation in epoxyclay nanocomposites. Chem. Mater. 7, 2144–2150. Laza, A.L., Jaber, M., Miehe-Brendle, J., Demais, H., Le Deit, H., Delmotte, L., Vidal, L., 2007. Green nanocomposites: synthesis and characterization. J. Nanosci. Nanotechnol. 7, 3207–3213. Lebaron, P.C., Wang, Z., Pinnavaia, T.J., 1999. Polymer-layered silicate nanocomposites: an overview. Appl. Clay Sci. 15, 11–29. Lee, D.C., Jang, L.W., 1996. Preparation and characterization of PMMA-clay hybrid composite by emulsion polymerization. J. Appl. Polym. Sci. 61, 1117–1122. Lei, Y., Wu, Q., Clemons, C.M., Yao, F., Xu, Y., 2007. Influence of nanoclay on properties of HDPE/wood composites. J. Appl. Polym. Sci. 106, 3958–3966. Lepoittevin, B., Pantoustier, N., Devalckenaere, M., Alexandre, M., Kubies, D., Calberg, C., Jerome, R., Dubois, P., 2002. Poly(epsilon-caprolactone)/clay nanocomposites by in-situ intercalative polymerization catalyzed by dibutyltin dimethoxide. Macromolecules 35, 8385–8390. Magalhaes, N.F., Andrade, C.T., 2009. Thermoplastic corn starch/clay hybrids: effect of clay type and content on physical properties. Carbohydr. Polym. 75, 712–718. Mangiacapra, P., Gorrasi, G., Sorrentino, A., Vittoria, V., 2006. Biodegradable nanocomposites obtained by ball milling of pectin and montmorillonites. Carbohydr. Polym. 64, 516–523. Manias, E., Touny, A., Wu, L., Strawhecker, K., Lu, B., Chung, T.C., 2001. Polypropylene/montmorillonite nanocomposites. Review of the synthetic routes and materials properties. Chem. Mater. 13, 3516–3523.

Chapter

13.1


703

Marras, S.I., Zuburtikudis, I., Panayiotou, C., 2007. Nanostructure vs. microstructure: morphological and thermomechanical characterization of poly(L-lactic acid)/layered silicate hybrids. Eur. Polym. J. 43, 2191–2206. Mathias, L.J., Davis, R.D., Jarrett, W.L., 1999. Observation of a and g crystal forms and amorphous regions of nylon 6-clay nanocomposites using solid-state 15N nuclear magnetic resonance. Macromolecules 32, 7958–7960. Mehrotra, V., Giannelis, E.P., 1992. Nanometer scale multilayers of electroactive polymers— intercalation of polypyrrole in mica-type silicates. Solid State Ion. 51, 115–122. Messersmith, P.B., Giannelis, E.P., 1993a. Polymer-layered silicates nanocomposites—in-situ intercalative polymerization of epsilon-caprolactone in layered silicates. Chem. Mater. 5, 1064–1066. Messersmith, P.B., Giannelis, E.P., 1993b. Synthesis and characterization of layered silicateepoxy nanocomposites. Chem. Mater. 6, 1719–1725. Messersmith, P.B., Giannelis, E.P., 1995. Synthesis and barrier properties of poly(e-caprolactone)layered silicate nanocomposites. J. Polym. Sci. A 33, 1047–1057. Mishra, A.K., Nando, G.B., Chattopadhyay, S., 2008. Exploring preferential association of laponite and cloisite with soft and hard segments in TPU-clay nanocomposite prepared by solution mixing technique. J. Polym. Sci. B 46, 2341–2354. Nguyen, Q.T., Baird, D.G., 2006. Preparation of polymer–clay, nanocomposites and their properties. Adv. Polym. Technol. 25, 270–285. Oh, J.K., Drumright, R., Siegwart, D.J., Matyjaszewski, K., 2008. The development of microgels/ nanogels for drug delivery applications. Prog. Polym. Sci. 33, 448–477. Okada, A., Usuki, A., 1996. The chemistry of polymer-clay hybrids. Mater. Sci. Eng. C 3, 109–115. Olabarrieta, I., Gallstedt, M., Ispizua, I., Sarasua, J.R., Hedenqvist, M.S., 2006. Properties of aged montmorillionite-wheat gluten composite films. J. Agric. Food Chem. 54, 1283–1288. Osman, M.A., Mittal, V., Morbidelli, M., Suter, U.W., 2003. Polyurethane adhesive nanocomposites as gas permeation barrier. Macromolecules 36, 9851–9858. Owusu-Adom, K., Guymon, C.A., 2008. Photopolymerization kinetics of poly(acrylate)-clay composites using polymerizable surfactants. Polymer 49, 2636–2643. Ozkoc, G., Kemaloglu, S., Quaedflieg, M., 2010. Production of poly(lactic acid)/organoclay nanocomposite scaffolds by microcompounding and polymer/particle leaching. Polym. Compos. 31, 674–683. Park, H.M., Li, X.C., Jin, C.Z., Park, C.Y., Cho, W.J., Ha, C.S., 2002. Preparation and properties of biodegradable thermoplastic starch/clay hybrids. Macromol. Mater. Eng. 287, 553–558. Park, H.M., Liang, X.M., Mohanty, A.K., Misra, M., Drzal, L.T., 2004. Effect of compatibilizer on nanostructure of the biodegradable cellulose acetate/organoclay nanocomposites. Macromolecules 37, 9076–9082. Paul, D.R., Robeson, L.M., 2008. Polymer nanotechnology: nanocomposites. Polymer 49, 3187–3204. Pavlidou, S., Papaspyrides, C.D., 2008. A review on polymer-layered silicate nanocomposites. Prog. Polym. Sci. 33, 1119–1198. Peppas, N.A., Bures, P., Leobandung, W., Ichikawa, H., 2000. Hydrogels in pharmaceutical formulations. Eur. J. Pharm. Biopharm. 50, 27–46. Pinnavaia, T.J., Beall, G., 2000. Polymeric Clay Nanocomposites. Wiley, New York. Pojanavaraphan, T., Magaraphan, R., 2010. Fabrication and characterization of new semiconducting nanomaterials composed of natural layered silicates (Naþ-Mmt), natural rubber (NR), and polypyrrole (PPy). Polymer 51, 1111–1123. Porter, D., Metcalfe, E., Thomas, M.J.K., 2000. Nanocomposite fire retardants—a review. Fire Mater. 24, 45–52.

704


Qiu, H.X., Yu, J.G., Zhu, J.L., 2005. Polyacrylate/(chitosan modified montmorillonite) nanocomposite: water absorption and photostability. Polym. Polym. Compos. 13, 167–172. Ray, S.S., Bousmina, M., 2005. Biodegradable polymers and their layered silicate nano composites: in greening the 21st century materials world. Prog. Mater. Sci. 50, 952–1079. Ray, S.S., Okamoto, M., 2003a. Polymer/layered silicate nanocomposites: a review from preparation to processing. Prog. Polym. Sci. 28, 1539–1641. Ray, S.S., Okamoto, M., 2003b. Biodegradable polylactide and its nanocomposites: opening a new dimension for plastics and composites. Macromol. Rapid Commun. 24, 815–840. Reinholdt, M.X., Kirkpatrick, R.J., Pinnavaia, T.J., 2005. Montmorillonite-poly(ethylene oxide) nanocomposites: interlayer alkali metal behavior. J. Phys. Chem. B 109, 16296–16303. Rhim, J.-W., 2007. Potential use of biopolymer-based nanocomposite films in food packaging applications. Food Sci. Biotechnol. 16, 691–709. Rhim, J.-W., 2011. Effect of clay contents on mechanical and water vapor barrier properties of agar-based nanocomposite films. Carbohydr. Polym. 86, 691–699. Rhim, J.W., Lee, J.H., Kwak, H.S., 2005. Mechanical and water barrier properties of soy protein and clay mineral composite films. Food Sci. Biotechnol. 14, 112–116. Ruiz-Hitzky, E., Aranda, P., 1990. Polymer-salt intercalation complexes in layer silicates. Adv. Mater. 2, 545–547. Ruiz-Hitzky, E., Ariga, K., Lvov, Y., 2008. Bio-inorganic Hybrid Nanomaterials. Strategies, Syntheses, Characterization and Application. Wiley-VCH Verlag, Weinheim. Salcedo, I., Aguzzi, C., Sandri, G., Bonferoni, M.C., Mori, M., Cerezo, P., Sanchez, R., Viseras, C., Caramella, C., 2012. In vitro biocompatibility and mucoadhesion of montmorillonite chitosan nanocomposite: a new drug delivery. Appl. Clay Sci. 135, 131–137. Sandıá, G., Carrado, K.A., Joachin, H., Lu, W., Prakash, J., 2003. Polymer nanocomposites for lithium battery applications. J. Power Sour. 119–121, 492–496. Schaefer, D.W., Justice, R.S., 2007. How nano are nanocomposites? Macromolecules 40, 8501–8517. Schmidt-Rohr, K., Clauss, J., Spiess, H.W., 1992. Correlation of structure, mobility, and morphological information in heterogeneous polymer materials by two-dimensional widelineseparation NMR spectroscopy. Macromolecules 25, 3273–3277. Scocchi, G., Posocco, P., Fermeglia, M., Pricl, S., 2007. Polymer-clay nanocomposites: a multiscale molecular modeling approach. J. Phys. Chem. B 111, 2143–2151. Sikdar, D., Katti, K.S., Katti, D.R., 2008. Molecular interactions alter clay and polymer structure in polymer clay nanocomposites. J. Nanosci. Nanotechnol. 8, 1638–1657. Sikdar, D., Katti, D.R., Katti, K.S., Bhowmik, R., 2010. Tailoring crystallinity and nanomechanical properties of clay polymer nanocomposites: a molecular dynamics study. Int. J. Multiscale Comput. Eng. 8, 561–584. Silvino, A.C., De Souza, K.S., Dahmouche, K., Dias, M.L., 2012. Polylactide/clay nanocomposites: a fresh look into the in situ polymerization process. J. Appl. Polym. Sci. 124, 1217–1224. Sinsawat, A., Anderson, K.L., Vaia, R.A., Farmer, B.L., 2003. Influence of polymer matrix composition and architecture on polymer nanocomposite formation: coarse-grained molecular dynamics simulation. J. Polym. Sci. B 41, 3272–3284. Stretz, H.A., Paul, D.R., Li, R., Keskkula, H., Cassidy, P.E., 2005. Intercalation and exfoliation relationships in melt-processed poly(styrene-co-acrylonitrile)/montmorillonite nanocomposites. Polymer 46, 2621–2637. Takahashi, S., Goldberg, H.A., Feeney, C.A., Karim, D.P., Farrell, M., O’Leary, K., Paul, D.R., 2006. Gas barrier properties of butyl rubber/vermiculite nanocomposite coatings. Polymer 47, 3083–3093.

Chapter

13.1


705

Talibudeen, O., 1950. Interlamellar adsorption of protein monolayers on pure montmorillonoid clays. Nature 166, 236. Theng, B.K.G., 1979. Formation and Properties of Clay-Polymer Complexes. Elsevier, Amsterdam. Theng, B.K.G., 1982. Clay-polymer interactions—summary and perspectives. Clays Clay Miner. 30, 1–10. Thomas, S., Stephen, R. (Eds.), 2010. Rubber Nanocomposites. J. Wiley & Sons, Singapore. Tian, Y., Yu, H., Wu, S.H., Shen, J., 2004. Study on structure and properties of EVA/Mmt nanocomposites prepared using one-step melt intercalation technology. Acta Polym. Sinica. 1, 129–131. Tjong, S.C., 2006. Structural and mechanical properties of polymer nanocomposites. Mater. Sci.. Eng. R 53, 73–197. Tjong, S.C., Meng, Y.Z., Hay, A.S., 2002. Novel preparation and properties of polypropylenevermiculite nanocomposites. Chem. Mater. 14, 44–51. Tortora, M., Vittoria, V., Galli, G., Ritrovati, S., Chiellini, E., 2002. Transport properties of modified montmorillonite-poly(epsilon-caprolactone) nanocomposites. Macromol. Mater. Eng. 287, 243–249. Urbanczyk, L., Hrobarikova, J., Calberg, C., Je´roˆme, R., Grandjean, J., 2006. Motional heterogeneity of intercalated species in modified clays and poly(e-caprolactone)/clay nanocomposites. Langmuir 22, 4818–4824. Usuki, A., Hasegawa, N., 2005. Polymer-clay nanocomposites. Adv. Polym. Sci. 179, 135–195. Usuki, A., Kojima, Y., Kawasumi, M., Okada, A., Fukushima, Y., Kurauchi, T., Kamigaito, O., 1993. Synthesis of Nylon 6-clay hybrid. J. Mater. Res. 8, 1179–1184. Utracki, L.A., 2004. Clay-Containing Polymeric Nanocomposites. Rapra Tech. Ltd., London. Vaia, R.A., Giannelis, E.P., 1999a. Lattice model of polymer melt intercalation in organicallymodified layered silicates. Macromolecules 30, 7990–7999. Vaia, R.A., Giannelis, E.P., 1999b. Polymer melt intercalation in organically-modified layered silicates: model predictions and experiment. Macromolecules 30, 8000–8009. Vaia, R.A., Giannelis, E.P., 2001. Polymer nanocomposites: status and opportunities. MRS Bull. 26, 394–401. Vaia, R.A., Vasudevan, S., Krawiec, W., Scanlon, L.G., Giannelis, E.P., 1995. New polymer electrolyte nanocomposites—melt intercalation of poly(ethylene oxide) in mica-type silicates. Adv. Mater. 7, 154–156. Vanderhart, D.L., Asano, A., Gilman, J.W., 2001a. Solid-state NMR investigation of paramagnetic nylon-6 clay nanocomposites. 2. Measurement of clay dispersion, crystal stratification, and stability of organic modifiers. Chem. Mater. 13, 3796–3809. Vanderhart, D.L., Asano, A., Gilman, J.W., 2001b. Solid-state NMR Investigation of paramagnetic nylon-6 clay nanocomposites. 1. Crystallinity, morphology, and the direct influence of Fe3þ on nuclear spins. Chem. Mater. 13, 3781–3795. Vertuccio, L., Gorrasi, G., Sorrentino, A., Vittoria, V., 2009. Nano clay reinforced PCL/starch blends obtained by high energy ball milling. Carbohydr. Polym. 75, 172–179. Vicente Vilas, V., Mathiasch, B., Huth, J., Kratz, J.V., De La Rosa, S.R., Michel, P., Schaefer, T., 2010. Synthesis and characterization of the hybrid clay-based material montmorillonitemelanoidin: a potential soil model. Soil Sci. Soc. Am. J. 74, 2239–2245. Wang, M.S., Pinnavaia, T.J., 1994. Clay polymer nanocomposites formed from acidic derivatives of montmorillonite and an epoxy-resin. Chem. Mater. 6, 468–474. Wang, W., Wang, A., 2009. Preparation, characterization and properties of superabsorbent nanocomposites based on natural guar gum and modified rectorite. Carbohydr. Polym. 77, 891–897.

706


Wang, Y., Zhang, L., Tang, C.H., Yu, D., 2000. Preparation and characterization of rubber-clay nanocomposites. J. Appl. Polym. Sci. 78, 1879–1883. Wang, D.Y., Zhu, J., Yao, Q., Wilkie, C., 2002. A comparison of various methods for the preparation of polystyrene and poly(methyl methacrylate) clay nanocomposites. Chem. Mater. 14, 3837–3843. White, L.A., 2004. Preparation and thermal analysis of cotton-clay nanocomposites. J. Appl. Polym. Sci. 92, 2125–2131. Wu, C.-J., Gaharwar, A.K., Schexnailder, P.J., Schmidt, G., 2011. Development of biomedical polymer-silicate nanocomposites: a materials science perspective. Materials 3, 2986–3005. Xu, R.J., Manias, E., Snyder, A.J., Runt, J., 2001. New biomedical poly(urethane urea)-layered silicate nanocomposites. Macromolecules 34, 337–339. Xu, R.J., Manias, E., Snyder, A.J., Runt, J., 2003. Low permeability biomedical polyurethane nanocomposites. J. Biomed. Mater. Res. A 64A, 114–119. Yang, L., Phua, S.L., Teo, J.K.H., Toh, C.L., Lau, S.K., Ma, J., Lu, X., 2011. A biomimetic approach to enhancing interfacial interactions: polydopamine-coated clay as reinforcement for epoxy resin. ACS Appl. Mater. Interf. 3, 3026–3032. Yoon, P.J., Hunter, D.L., Paul, D.R., 2003a. Polycarbonate nanocomposites: part 2. degradation and color formation. Polymer 44, 5341–5354. Yoon, P.J., Hunter, D.L., Paul, D.R., 2003b. Polycarbonate nanocomposites. Part 1. Effect of organoclay structure on morphology and properties. Polymer 44, 5323–5339. Zanetti, M., Lomakin, S., Camino, G., 2000. Polymer layered silicate nanocomposites. Macromol. Mater. Eng. 279, 1–9. Zhang, L., Wang, Y.Z., Wang, Y.Q., Sui, Y., Yu, D.S., 2000. Morphology and mechanical properties of clay/styrene-butadiene rubber nanocomposites. J. Appl. Polym. Sci. 78, 1873–1878. Zhang, L., Xu, J., Hou, G., Tang, H., Deng, F., 2007. Interactions between Nafion resin and protonated dodecylamine modified montmorillonite: a solid state NMR study. J. Colloid Interface Sci. 311, 38–44. Zhao, J., Morgan, A.B., Harris, J.D., 2005. Rheological characterization of polystyrene-clay nanocomposites to compare the degree of exfoliation and dispersion. Macromolecules 46, 8641–8660. Zhao, R., Torley, P., Halley, P.J., 2008. Emerging biodegradable materials: starch- and proteinbased bio-nanocomposites. J. Mater. Sci. 43, 3058–3071. Zhuang, H., Zheng, J.P., Gao, H., De Yao, K., 2007. In vitro biodegradation and biocompatibility of gelatin/montmorillonite-chitosan intercalated nanocomposite. J. Mater. Sci. Mater. Med. 18, 951–957. Zhuk, A., Mirza, R., Sukhishvili, S., 2011. Multiresponsive clay-containing layer-by-layer films. ACS Nano 5, 8790–8799.

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