Characterization And Analysis Of The Electrical Properties Of A Metal Filled Polymer PDF Download

This book is dedicated to the memory of Pierre Gilles de Gennes (1932-2007). The depth, breadth, beauty and shear quantity of his physics and science is phenomenal. It is probably safe to say that every physicist interested in polymer physics today is influenced by work of de Gennes. This volume is concerned with diverse topics related to filled polymers engineering. Particle-filled polymers provide a remarkable and exciting arena for mesoscopic physics because they offer more degrees of design freedom to optimize response than is available with single-phase materials. The past two decades have seen a blossoming of interest in soft compounds filled with a variety of filler particles ranging from particles to fibers to nanotubes; examples include plasto-ferrites used for microwave absorbers and flexible magnets, and carbon black (CB) filled polymers used for current limiters, or in tires. In view of this activity, it is vital to understand the physical properties (and their couplings) of this broad category of condensed matter sometimes referred to collectively as finely divided materials. Filler particles dispersed in a polymeric melt represents a stochastic dynamical system far from equilibrium. Filler particles are constantly adsorbed and desorbed; at the same time polymer chains obey random walk statistics and eventually entangle. These processes are both inherently stochastic, and yield heterogeneous materials. A general feature that emerges from recent experiments is that, even under well-controlled conditions of fabrication, the steady-state associated with quenched configurational disorder represents a useful model for the study of the interplay of disorder and interactions. The mouldability of these composites into complex shapes is another advantage, and the properties of this class of filled polymers may be valuable to several related industries due to the versatile engineering and cost effectiveness. To this end, the current book emphasizes those properties of greatest utility to physicists and engineers interested in characterizing such complex materials. The contributors to this book have endeavored to be selective, choosing and documenting those results to have the highest relevance and reliability. There was no attempt to be exhaustive and comprehensive. The careful selection of the topics included, however, suggests that the most attractive features of these particulate composites, is that their dielectric and magnetic properties can be varied over a wide range by the choice of the shape, size and connectivity of the constituents in the polymeric matrix. This volume contains six survey contributions describing several active areas in this field of research. Carbon nanotubes (CNTs), cylindrical macromolecules of carbon, have been the focus of intense research during recent years mainly because of their rich structural (molecular scale) and physical (electronic, mechanical, and optical) properties, which may also be tuned functionalizing the internal constituents of the tubes, i.e. filled by a variety of materials, and the sidewalls. CNTs/polymer composites are among the most cited candidate materials for nanoelectronics, a dominant position that stems mostly from their intrinsic structural and electronic properties. Although the flexible CNTs/polymer composite could prove to be a central part of future foldable flat screen display, or flexible electronic paper, there is a long way to go. The a priori prediction of mechanical and electrical properties remains an outstanding problem in materials physics. Within this context, Mdarhri and Brosseau review, in the first chapter, the analysis of the electromagnetic behavior of CNTs in a polymer matrix. More specifically, they showed that few analytical methods can deal with this issue beyond mean-field and phenomenological arguments. In the second chapter, Youngs considers non-percolating and percolating composite materials. The interplay of wave and charge transport and disorder has been a recurring theme in condensed matter physics. The didactic style of the chapter should make it generally useful to those interested in conductor-insulator mixtures because this kind of heterostructures provides the opportunity for studying generic problems appearing in many strongly correlated systems, for example percolation and scaling, which play important roles in metal-insulator transitions. The peculiar properties of the response of these materials to electromagnetic waves have important implications in the design of structure with optimized electromagnetic properties. In Achour's chapter the focus will be on the microwave properties of CB filled epoxies. After an incisive introduction to the physical models describing the electromagnetic properties of heterogeneous materials and an extensively referenced guide to important bulk characteristics of CB filled polymers, the author turns to a presentation of experimental results with emphasis on the characterization of the efffective permittivity and conductivity of these composite materials. The chapter by Brosseau reviews what is current with respect to the underlying physics of the mesostructure and elasticity network in filled polymers. In addition, he reports the results of experimental studies of the mesostructure, thermodynamics and rheology of mechanically mixed linear low-density polyethylene CB composites. The network structure, cristallinity and linear viscoelastic behavior of these materials are characterized by a combination of experimental techniques including direct current conductivity, sorption kinetics, X-ray scattering, differential scanning calorimetry and rheology. Next, Krakovsky and Ikeda present a comprehensive overview of the network and viscoelastic properties of filled polymers, one of the most venerable subjects in this area. A physically based description of the principal ideas and models that have been used to describe the viscoelastic (Payne effect) and hyperelastic (Mullins effect) behaviors is followed by a scholarly section on the formation of polymer and filler networks, i.e. spherical primary particles or fractal-like aggregates formed from them. In the final chapter, Guo and co-workers discuss physical and physico-chemical properties of ceramic nanoparticle-based polymeric nanocomposites. Because of their widely tunable properties, polymeric nanocomposites provide the ideal playground to model and study complex many body systems. By using nanoparticle functionalization, the authors explored the formed particle/matrix interfacial bonding. A relatively small number of contributions can only skim the surface of filled polymers engineering. Our goal is only to illustrate the current status in the understanding of the properties of these finely dispersed media. Clearly, the interplay between processing, mesostructure, and properties is an important engineering and scientific concern. Both the editor and contributors of this volume would feel well rewarded if this book helps relieve some of the problems of finding useful information on the mesostructure, elasticity network, and macroscopic properties of filled polymers.