Multiscale Modeling and Computation of Liquid Crystal Polymers, Polymer Blends, and Polymer Nanocomposites: Investigation of Rheology and Material Properties


Book Description

High-performance polymeric materials such as liquid crystal polymers and polymer nano-particle composites have many military applications. The project aimed to study the mesoscopic structure formation during flow processing and characterization of material properties in solid states. Significant progress has been made to model the materials and to understand their rheological properties in melt or solution processing. Electrical and thermal conduction properties of the nanocomposites are characterized by the low volume fraction asymptotic approach. More anisotropic molecular configuration and their impact to the macroscopic material properties have been investigated. Applications of the models and numerical tools developed for complex fluids are used to important biological applications.




Rheology and Processing of Liquid Crystal Polymers


Book Description

Liquid crystal polymers (LCPs) have many strange properties that may be utilized to advantage in the processing of products made from them and their blends with isotropic polymers. This volume (volume 2 in the series Polymer Liquid Crystals) deals with their strange flow behaviour and the models put forward to explain the phenomena that occur in such polymers and their blends. It has been known for some time that small ad ditions of a thermotropic LCP to isotropic polymers not only gives an improvement in the strength and stiffness of the blend but improves the processability of the blend over that of the isotropic polymer. In the case of lyotropic LCPs, it is possible to create a molecular composite in which the reinforcement of an isotropic polymer is achieved at a molecular level by the addition of the LCP in a common solvent. If the phenomena can be fully understood both the reinforcement and an increase in the proces sability of isotropic polymers could be optimized. This book is intended to illustrate the current theories associated with the flow of LCPs and their blends in the hope that such an optimization will be achieved by future research. Chapter 1 introduces the subject of LCPs and describes the ter minology used; Chapter 2 then discusses the more complex phenomena associated with these materials. In Chapter 3, the way in which these phe nomena may be modelled using hamiltonians is fully covered.




Multiscale Modelling of Polymer Properties


Book Description

Modelling in polymer materials science has experienced a dramatic growth in the last two decades. Advances in modeling methodologies together with rapid growth in computational power have made it possible to address increasingly complex questions both of a fundamental and of a more applied nature.Multiscale Modelling of Polymer Properties assembles research done on modeling of polymeric materials from a hierarchical point of view, in which several methods are combined in a multilevel approach to complex polymeric materials. Contributions from academic and industrial experts are organized in two parts: the first one addresses the methodological aspects while the second one focuses on specific applications. The book aims at comprehensively assessing the current state of the field, including the strengths and shortcomings of available modelling techniques, and at identifying future needs and trends. * Several levels of approximation to the field of polymer modelling; ranging from first-principles to purely macroscopic * Contributions from both academic and industrial experts with varying fields of expertise* Assesses current state of this emerging and rapidly growing field




Thermotropic Liquid Crystal Polymer Blends


Book Description

In recent years, studies by both industry and academic researchers have opened the door to improving performance and reducing costs of these new materials. The particular structure and morphology of LCPs, as well as their peculiar rheological behavior, have stimulated researchers to develop new theoretical models and new characterization and processing techniques to more fully understand and utilize LCPs. Although the scientific literature is very rich in data on the synthetic techniques and on the relations between structure and phase behavior of these new polymers, the understanding of the rheological and processing aspects is still far from satisfactory-particularly in the case of LCP blends. In fact, although an appreciable number of patents and scientific papers have appeared describing the phase behavior, the rheology, and the mechanical properties of many of these polyblends, several aspects of the relations between processing and morphology, and between morphology and properties of these materials are still obscure or even controversial. Now, this new book, written by leading researchers, provides an up-to-date guide and reference to the processing, rheology and applications of pure LCPs and LCP blends. The book concisely reviews the synthetic procedures for the production of LCPs and discusses the rheological behavior and processing methods. Plus, the book examines present and future applications areas of LCPs and LCP blends.




Multiphase Polymer Systems


Book Description

Phase morphology in multicomponent polymer-based systems represents the main physical characteristic that allows for control of the material design and implicitly the development of new plastics. Emphasizing properties of these promising new materials in both solution and solid phase, this book describes the preparation, processing, properties, and practical implications of advanced multiphase systems from macro to nanoscales. It covers a wide range of systems including copolymers, polymer blends, polymer composites, gels, interpenetrating polymers, and layered polymer/metal structures, describing aspects of polymer science, engineering, and technology. The book analyzes experimental and theoretical aspects regarding the thermal and electrical transport phenomena and magnetic properties of crucial importance in advanced technologies. It reviews the most recent advances concerning morphological, rheological, interfacial, physical, fire-resistant, thermophysical, and biomedical properties of multiphase polymer systems. Concomitantly the book deals with basic investigation techniques that are sensitive in elucidating the features of each phase. It also discusses the latest research trends that offer new solutions for advanced bio- and nanotechnologies. Introduces an overview of recent studies in the area of multiphase polymer systems, their micro- and nanostructural evolutions in advanced technologies, and provides future outlooks, new challenges and opportunities. Discusses multicomponent structures that offer enhanced physical, mechanical, thermal, electrical, magnetic, and optical properties adapted to current requirements of modern technologies. Covers a wide range of materials, such as composites, blends, alloys, gels and interpenetrating polymer networks. Presents new strategies for controlling the micro- and nanomorphology and the mechanical properties of multiphase polymeric materials. Describes different applications of multiphase polymeric materials in various fields, including automotive, aeronautics and space industry, displays, and medicine.




Thermotropic Liquid Crystal Polymers


Book Description

Liquid crystal polymers are sometimes called super polymers--with good reason. Their wide range of exceptional properties and ease of processing make them design candidates for many demanding applications. This new book provides a thorough review of LCP technology with the emphasis on the chemistry, synthesis and characterization of the material in its many variants. Additional chapters cover processing and applications. From the Editor's Preface The field of thermotropic liquid crystalline polymers has grown substantially in the last two decades, with fundamental research, publications, commercial products, and patents. In the 1980's, Dr. Ralph Miano led my colleagues and me at Hoechst Celanese in commercializing the first thermotropic liquid crystalline polymers, based on Dr. Gordon Calundann's composition patents. Today, more than seven companies have produced thermotropic liquid crystalline polymer materials, with at least 50 variants available. Hence, it is timely to compile a comprehensive review on the nature of this type of material and the ongoing progress in this field.... The goals of this book are to summarize previous work, provide new insights into this class of polymers, and add to the understanding of the formation of liquid crystallinity. This book covers a wide range of topics and addresses different disciplines in the field. The chapters are arranged as a learning scheme for the professional, from basic science to applied engineering. The first few chapters summarize the syntheses of various polyester, polyester-amid, and polyimide liquid crystalline polymers. The science and origins of liquid crystal formation are revealed. Next, we introduce the characterizations of these materials by their different chemical and physical aspects. Because most commercially available thermotropic liquid crystalline polymers have been used in the form of composites, we have also incorporated a chapter on polymer blends, detailing blending mechanisms and resultant properties. Two chapters on thermosetting liquid crystalline polymers integrate them with other topics, because of their unique importance and their applications for microelectronics and packaging. The final chapter deals with the engineering and processing aspects of thermoplastic liquid crystalline polymers for a variety of applications.




Modeling and Simulation in Polymers


Book Description

Filling a gap in the literature and all set to become the standard in this field, this monograph begins with a look at computational viscoelastic fluid mechanics and studies of turbulent flows of dilute polymer solutions. It then goes on discuss simulations of nanocomposites, polymerization kinetics, computational approaches for polymers and modeling polyelectrolytes. Further sections deal with tire optimization, irreversible phenomena in polymers, the hydrodynamics of artificial and bacterial flagella as well as modeling and simulation in liquid crystals. The result is invaluable reading for polymer and theoretical chemists, chemists in industry, materials scientists and plastics technologists.




Liquid Crystalline Polymers


Book Description

This book introduces various applications of liquid crystalline polymers as the emerging new class of high performance novel materials. The authors detail the advantageous properties of these LCs including optical anisotropic, transparency and easy control over structure. This interdisciplinary work includes valuable input from international projects with special focus on the use of liquid crystalline polymers and/or nanocomposites.




Mechanical and Thermophysical Properties of Polymer Liquid Crystals


Book Description

may never overcome the effects of hysteresis and stress (see Chapters 6 and 12). The first sentence of the reference work, Handbook of Liquid Crystals, reads: The terms liquid crystals, crystalline liquid, mesophase, and mesomorphous state are used synonymously to describe a state of aggregation that exhibits a molecular order in a size range similar to that of a crystal but acts more or less as a viscous liquid: [2] In other words, molecules within a liquid crystalline phase possess some orientational order and lack positional order; furthermore, the shape of a liquid crystalline sample is determined by the vessel in which it is contained rather than by the orientational order of its aggregated molecules. The authors recognized the limitations and imprecision of this definition but, like others preceding them, could not devise a simple and generally applicable one that is better. Regardless, the terms 'liquid crystal' and 'mesophase' should not be used interchangeably. As mentioned above, all liquid crystals are mesophases, but all mesophases are not liquid crystals. Recent studies, employing elaborate and sophisticated analytical techniques, have permitted finer distinctions between classical crystals and mesophases. At the same time, they have made definitions like that from the Handbook of Liquid Crystals somewhat obsolete for reasons other than terminology. One part of the problem arises from the use of a combination of bulk properties (like flow) and microscopic properties (like molecular ordering) within the same definition.




Liquid-Crystal Polymers


Book Description

Drawing a picture of the current situation of this new field, this volume both summarizes the past achievements and analyzes the present unsolved problems.