Nanofiller-polymer interface

In Paragraph 2.3 and, in particular, in Tables 2.3, 2.4 and 2.5 data and comments were given on the nanofiller-polymer interface, arising from TEM and SEM microscopy as the characterization techniques. In this paragraph, what available in the literature is reviewed. 

Zhu AJ, Stemstein SS (2003) Nonlinear viscoelasticity of nanofilled polymers interfaces, chain statistics and properties recovery kinetics. Compos Sci Technol 63 1113-1126... 

Interfacial structure is known to be different from bulk structure, and in polymers filled with nanofillers possessing extremely high specific surface areas, most of the polymers is present near the interface, in spite of the small weight fraction of filler. This is one of the reasons why the nature of the reinforcement is different in nanocomposites and is manifested even at very low filler loadings (<10 wt%). Crucial parameters in determining the effect of fillers on the properties of composites are filler size, shape, aspect ratio, and filler-matrix interactions [2-5]. In the case of nanocomposites, the properties of the material are more tied to the interface. Thus, the control and manipulation of microstructural evolution is essential for the growth of a strong polymer-filler interface in such nanocomposites. 

It is a common phenomenon that the intercalated-exfoliated clay coexists in the bulk and in the interface of a blend. Previous studies of polymer blend-clay systems usually show that the clay resides either at the interface [81] or in the bulk [82]. The simultaneous existence of clay layers in the interface and bulk allows two functions to be attributed to the nanoclay particles one as a compatibilizer because the clays are being accumulated at the interface, and the other as a nanofiller that can reinforce the rubber polymer and subsequently improve the mechanical properties of the compound. The firm existence of the exfoliated clay layers and an interconnected chain-like structure at the interface of CR and EPDM (as evident from Fig. 42a, b) surely affects the interfacial energy between CR and EPDM, and these arrangements seem to enhance the compatibility between the two rubbers. 

The pol5mier nanocomposite field has been studied heavily in the past decade. However, polymier nanocomposite technology has been around for quite some time in the form of latex paints, carbon-black filled tires, and other pol5mier systems filled with nanoscale particles. However, the nanoscale interface nature of these materials was not truly understood and elucidated until recently [2 7]. Today, there are excellent works that cover the entire field of polymer nanocomposite research, including applications, with a wide range of nanofillers such as layered silicates (clays), carbon nanotubes/nanofibers, colloidal oxides, double-layered hydroxides, quantum dots, nanocrystalline metals, and so on. The majority of the research conducted to date has been with organically treated, layered silicates or organoclays. 

Demonstrate proof of concept , that is, to achieve interfacing electronically active nanofillers with polymers. More generally for the manufacturing sector, polymer is synonymous of flexible, thus the development of deposition techniques fully compatible with plastic substrates, low temperature processes and solution processable materials, and suitable for flexible substrates for roll-to-roll manufacturing technologies is mandatory. 

A speciality of such nanocomposites is the very high surface of well dispersed nanofillers, which results in a very high interfacial area. Here, the behavior of the polymer chains near the interface is influenced by the interaction with the filler, leading to an interphase with new properties which aheady at low amounts of nanofillers can determine the nanocomposite s properties. In addition, quite big effects are observed aheady at quite low filler loadings, especially if the filler has an anistropic shape. As an example, in thermoplastic polymers electrical conductivity can be reached with carbon nanotubes even below 1 wt% addition. 

Tailoring the properties of polymers with the inclusion of nanometric carbon depends on many factors. Among them, the parameters most taken into account are (a) the size, structure and distribution of the nanofiller in the matrix and (b) the interface between the nanofillers and the matrix. This chapter focuses mainly on the effects that functionalization and concentration of nanofillers have in the storage modulus and tribological properties of polymer nanocomposites reinforced with NDs, CNTs and graphene, describing briefly the hardness and scratching performance achieved in these nanocomposites. 

Roohani M, Habibi Y, Belgacem NM et al (2008) Cellulose whiskers reinforced polyvinyl alcohol copol Tners nanocomposites. Eur Polym J 44 2489-2498 Ruiz MM, Cavaille JY, Dufresne A et al (2000) Processing and characterization of new thermoset nanocomposites based on cellulose whiskers. Compos Interface 7 117-131 Ruiz MM, Cavaille JY, Dufresne A et al (2001) New waterborne epoxy coatings based on cellulose nanofillers. Macromol Symp 16 211-222 Saito T, Nishiyama Y, Putaux JL et al (2006) Homogeneous suspensions of individualized microfibrils from TEMPO-catalyzed oxidation of native cellulose. Biomacromolecules 7 1687-1691... 

Composites are defined in a lUPAC (International Union of Pure and Applied Chemistry) technical report as multicomponent materials comprising multiple different (non-gaseous) phase domains in which at least one type of phase domain is a continuous phase [1], whereas elsewhere the notation the components as well as the interface between them can be physically identified is added [2], Polymer nanocomposites are a group of materials defined as polymers in which a small amount (i.e., a few wt%) of nanofillers (1-lOOnm in size) are homogeneously distributed. Hybrid materials consist of both organic and inorganic components ... 

The electrical and optical properties of polymer-inorganic nanocomposites depend on the characteristics of the semiconductor NCs and degree of interaction between the nanofillers and polymer matrix. To obtain desirable properties, organic-inorganic nanocomposites usually require fine-tuning of the size, topology, and spatial assembly of individual domains and their interfaces. 

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