Nanoscale particle structures thermal properties

Exfoliated nanoscale layered silicate particles have been seen to provide dramatic improvements in mechanical properties in polyamide systems [1]. Numerous studies have since attempted to achieve the same degree of reinforcement in an array of thermoset and thermoplastic polymer systems [2]. Layered silicate clays have been popular due to low cost, high surface area, and versatility of organic treatments available to make them compatible with a host of commercial polymer systems [3]. These clays are natmally available as tactoid structures consisting of several silicate layers stacked in crystalline lattice [4,5]. However, optimum reinforcement and improvement in thermal properties are obtained when tactoids are exfoliated into individual platelets [1-3,6-24]. 

An important idea that underpins much of nanotechnology is that by controlling composition, size, and structure at the nanoscale one can engineer almost any desired properties. This is particularly trae for NPs as demonstrated by their many varied technological apphcations. They also have considerable fundamental interest as one can study the emergence of bulk properties (i.e. electronic, chemical, stmctural, thermal, mechanical, and optical) as the number of atoms in the particle increases from one to many thousands. The aim of this chapter is to provide a broad introduction to NP systems, with particular attention paid to stmeture and its connection to various properties (so-called structure-property relationships). This chapter is divided into three main parts. First in Section 2.2, some general issues concerning the atomic structure of NPs and its dependence on various factors, such as particle size and the presence of a support, are discussed. Associated properties of NP systems, such as chemical... 

A well-accepted definition of nanocomposite material is that one of the phases has dimensions in the order of nanometers [51]. Roy et al. [52] present in their paper on alternative perspectives on nanocomposites a summary of features of particle properties when particle size decreases beyond a critical size. As dimensions reach nanoranges, interactions improve dramatically at the interfaces of phases, as do the effect of surface area/volume on the structure-property relationship of the material [53]. There is definite increase in the modulus of the material reinforced with composites, higher dimensional stability to thermal treatment, as well as enhanced barrier, membrane (conductive properties) and flame resistance. Thus, as Paul and Robeson [54] rightly put it, the synergistic advantage of nanoscale dimensions ( nano effect ) relative to larger-scale modifications is an important consideration ... 

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