The exceptional mechanical properties of polymers with heterogeneous structure, such as the high toughness of polyethylene and the excellent blast-protection capability of polyurea, are strongly related to their morphology and nanoscale structure. Different polymer microstructures, such as semicrystalline morphology and segregated nanophases, lead to coordinated molecular motions during deformation in order to preserve compatibility between the different material phases. To study molecular relaxation in polyethylene, a coarse-grained model of polyethylene was calibrated to match the local structural variable distributions sampled from supercooled atomistic melts. The coarse-grained model accurately reproduces structural properties, e.g., the local structure of both the amorphous and crystalline phases, and thermal properties, e.g., glass transition and melt temperatures, and dynamic properties: including the vastly different relaxation time scales of the amorphous and crystalline phases. A hybrid Monte Carlo routine was developed to generate realistic semicrystalline configurations of polyethylene. The generated systems accurately predict the activation energy of the alpha relaxation process within the crystalline phase. Furthermore, the models show that connectivity to long chain segments in the amorphous phase increases the energy barrier for chain slip within crystalline phase. This prediction can guide the development of tougher semicrystalline polymers by providing a fundamental understanding of how nanoscale morphology contributes to chain mobility. In a different study, the macroscopic shock response of polyurea, a phase segregated copolymer, was analyzed using density functional theory (DFT) molecular dynamics (MD) simulations and classical MD simulations. The two models predict the shock response consistently up to shock pressures of 15 GPa, beyond which the DFT-based simulations predict a softer response. From the DFT simulations, an analysis of bond scission was performed as a first step in developing a more fundamental understanding of how shock induced material transformations effect the shock response and pressure dependent strength of polyurea subjected to extreme shocks.

The first concern of scientists who are interested in synthetic polymers has always been, and still is: How are they synthesized? But right after this comes the question: What have I made, and for what is it good? This leads to the important topic of the structure-property relations to which this book is devoted. Polymers are very large and very complicated systems; their character ization has to begin with the chemical composition, configuration, and con formation of the individual molecule. The first chapter is devoted to this broad objective. The immediate physical consequences, discussed in the second chapter, form the basis for the physical nature of polymers: the supermolecular interactions and arrangements of the individual macromolecules. The third chapter deals with the important question: How are these chemical and physical structures experimentally determined? The existing methods for polymer characterization are enumerated and discussed in this chapter. The following chapters go into more detail. For most applications-textiles, films, molded or extruded objects of all kinds-the mechanical and the thermal behaviors of polymers are of pre ponderant importance, followed by optical and electric properties. Chapters 4 through 9 describe how such properties are rooted in and dependent on the chemical structure. More-detailed considerations are given to certain particularly important and critical properties such as the solubility and permeability of polymeric systems. Macromolecules are not always the final goal of the chemist-they may act as intermediates, reactants, or catalysts. This topic is presented in Chapters 10 and 11.

This book presents the state-of-the-art in multiscale modeling and simulation techniques for composite materials and structures. It focuses on the structural and functional properties of engineering composites and the sustainable high performance of components and structures. The multiscale techniques can be also applied to nanocomposites which are important application areas in nanotechnology. There are few books available on this topic.

Computational Methods for Microstructure-Property Relationships introduces state-of-the-art advances in computational modeling approaches for materials structure-property relations. Written with an approach that recognizes the necessity of the engineering computational mechanics framework, this volume provides balanced treatment of heterogeneous materials structures within the microstructural and component scales. Encompassing both computational mechanics and computational materials science disciplines, this volume offers an analysis of the current techniques and selected topics important to industry researchers, such as deformation, creep and fatigue of primarily metallic materials. Researchers, engineers and professionals involved with predicting performance and failure of materials will find Computational Methods for Microstructure-Property Relationships a valuable reference.

This collection of research and review papers is aimed at depicting the state of the art on the possible correlations between processing variables, obtained structure and special properties which this structure induces on the plastic part. The extraordinary capacity of plastics to modify their properties according to a particular structure is evidenced for several transformation processes and for many applications. The final common goal is to take profit of this peculiar capacity of plastics by inducing, through a suitable processing, a specific spatial organization.

This book contains a collection of original research papers which were presented in honor of the Bordon Award recipient, Professor Eric Baer, on the occasion of the 55th Meeting of the American Chemical Society (Atlanta, Georgia, March, 1981). The contributors are present or former colleagues and students who have worked with him in the Department of Macromolecular Science at Case Institute of Technology of Case Western Reserve University. Throughout his work, Eric Baer has attempted to find the relation ships of solid state structure and hierarchy to the resultant pro perties from which specific functions are derived. Although he has studied many seemingly unrelated subjects, from irreversible de formation, mechanics and yield processes in amorphous polymeric solids to structural organization and mechanical function of ten don, his unique goal has been to develop models from the real structure that would allow a quantitative description of properties. Today, this area of "microscience" is rapidly expanding as new and sophisticated applications of polymeric materials with multifunc tional properties are emerging from our understanding and control of the solid state. The wide-ranging ideas and the original ity of Professor Baer's contributions have stimulated many new concepts which are now widely accepted in the field of high polymers. The contributions to this volume represent many of the areas which he has explored.

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