POLYMER SCIENCE and TECHNOLOGY
| Polymer blends are a key component of current polymer research
and technology, because of their ease of production of new materials by
mixing and the diversity of properties that result. From scientific standpoint,
however, an increasing set of characterization techniques have also led
to an increased understanding of the mechanisms involved in polymers mixing,
their fundamental interactions, and how these interactions affect their
final properties. This link between molecular interactions and physical
and engineering properties continues to be an important challenge for both
scientific and industrial viewpoints, due to the increasing economical impact
of polymer blends and alloys in many domains affecting our everyday life.
Under these conditions and because polymer research remains a growing field, the authors of the present book decided to assemble in these chapters many aspects of the polymer blends research from laboratories around the world, in order to obtain an exhaustive image of this research topic. The book is divided in four parts, each one containing several chapters, which are dealing with a specific aspect from the polymer blends area. The firs part of the book, COMPATIBILIZATION AND MISCIBILITY, contains 9 chapters presenting the theoretical aspects concerning the compatibility, the miscibility and the ways to induce compatibilization of polymer blends, as following: Chapter 1. Compatibilization of Polymer Blends (by Rudolph D. Deanin and Margaret A. Manion) - presents the basic notions about polymer blends (from history and commercial importance of polymer blends to miscibility/immiscibility issues) and discusses several ways to realize the compatibilization of such polymer blends. Chapter 2. Compounding and Compatibilization of High-Performance Polymer Alloys and Blends (by Wen-Yen Chiang and Chi-Yuan Huang) - is dedicated to the most important polymer alloys (PC/ABS Alloy, Nylon 6/ABS Alloy, Polymer/PCL Alloy), polymer blends (POM/EPDM, POM/PU, POM/PTFE, POM/Fiber blends), and polymer composite (POM/Carbon Black Composite, POM/Glass Fiber Composite, LDPE/Magnetic Powder Composite, PP/Mica Composite, PP/Mg(OH)2 Composite), based on high-performance polymers. Chapter 3. Miscibility and Interfacial Behavior in Polymer-Polymer Mixtures (Toshiaki Ougizawa and Takashi Inoue) - deals with the correlation between the polymer-polymer miscibility and their interfacial properties (interfacial thickness and interfacial tension). Chapter 4. Miscibility and Relaxation Processes in Blends (by John M. G. Cowie, Valeria Arrighi) - presents the dynamic properties of polymer blends in the region of the glass transition and discusses those models that have been developed to explain the dynamics of polymer blends. The effect of blending on molecular motion below the glass transition is also discussed. The last section deals with the long-term properties of polymer blends, i.e. the physical aging process in both homogeneous and heterogeneous blends and composites. Chapter 5. Thermoplastic Rubbers via Dynamic Vulcanization (by Jozsef Karger-Kocsis) - this chapter is dedicated to the specific aspects of thermoplastic dynamic vulcanizates, polymer blends obtained by dynamic cross-linking of blends composed of thermoplastic resins and thermoset elastomers. Chapter 6. Thermosetting Polymer Blends: Miscibility, Crystallization, and Related Properties (by Qipeng Guo) - is dealing with some aspects related to thermosetting polymer blends based on epoxy resin (with either elastomers, thermoplastic polymers, PEO or PCL), novolac resin, and unsaturated polyester resin. Chapter 7. Computer Simulation of Spinodal Decomposition in Polymer Mixtures (by Takaaki Matsuoka). Computer simulations of the phase separation due to the spinodal decomposition (Cahn-Hilliard model) are presented by considering polymer characteristics. Chapter 8. Interactions and Phase Behavior of Polyester Blends (by Thomas S. Ellis) - presents some theoretical aspects and the most important blends based on polyesters. Chapter 9. Miscibility of Nylon 66/Santoprene Blends (by Gabriel O. Shonaike). Some of the properties of both components are highlighted, and the effects of blend composition on mechanical properties are presented. The second part of this book - CHARACTERIZATION - includes 7 chapters, as following: Chapter 10. High-Performance Polymer Blends and Alloys: Structure and Properties (by Martin Weber) - focuses on polymer blends and alloys based on polyarylethers, (polyethersulfone, polysulfone). |
Chapter 11. "Natural'' Polymer Alloys: PC/ABS Systems
(by Roberto Greco) - presents the characteristics of components, and the
properties of PC/SAN, and PC/ABS blends. Chapter 12. Properties of Thermotropic Liquid Crystalline Polymer Blends (by Tsung-Tang Hsieh, Carlos Tiu George P. Simon, Stuart R. Andrews, Graham Williams, Kuo-Huang Hsieh, Chao-Hsun Chen) - presents an analysis of the relationship between rheological properties, miscibility, and free volume of a thermotropic liquid crystalline polymer blend of two rigid chain copolyesters, Vestra A950 and HIQ45 (both of which presenting a p-hydroxybenzoic acid unit). Chapter 13. Polymer Liquid Crystals in High-Performance Blends (by Witold Brostow) - deals with the mechanical, thermal, and rheological properties of some polymer blends based on engineering polymers and polymer liquid crystals. Chapter 14. Structure-Property Relationships in Poly(aryl Ether Ketone) Blends (by Andy A. Goodwin, George P. Simon, Marcus D. Zipper) - presents a review of structure-property relationship of poly(ether ether ketone) blends, with a greater emphasis on the more commonly studied poly(ether ether ketone) blends. Chapter 15. Applications of X-Ray Photoelectron Spectroscopy and Secondary Ion Mass Spectrometry in Characterization of Polymer Blends (by Chi-Ming Chan Jingshen Wu and Yiu-Wing Mai) - focuses on two most powerful surface analysis techniques, XPS and SSIMS, which have been used extensively to characterize surface properties of polymer blends. Chapter 16. Emulsion Models in Polymer Blend Rheology (by René Muller) - deals with the most recent advances in the field of polymer blend rheology, based on the use of emulsion models, and allowing to develop quantitative relationship between rheological properties on the one hand, and morphological and interfacial properties on the other hand. The third part of the book - MORPHOLOGY - deals with some aspects related on the microstructure, the morphology and the deformation mechanisms characteristics to the polymer blends. Chapter 17. Microstructure of Multiphase Blends of Thermoplastics (by Barbara A. Wood) - presents the correlation between the morphology and the properties of polymer blends based on thermoplastic polymers. Chapter 18. Study on Morphology and Toughening Mechanisms in Polymer Blends by Microscopic Techniques (by Jingshen Wu, Chi-Ming Chan, Yiu-Wing Mai) - contains a brief overview of the basic principles of optical and electronic microscope and their applications in morphology characterization; a various methods developed for microscopically specimen preparation, and the technical details of some contrast enhancement techniques. Chapter 19. Deformation Mechanisms in Toughened PMMA (by Philippe Beguelin, Christopher J.G. Plummer, H.H. Kausch) - presents the possibilities to improve the PMMA properties, the correlation between the blends composition and their morphologies and the influence of the morphology on the properties of PMMA-based blends. Chapter 20. Impact Toughening Mechanisms in Glassy Polymers (by Y. Okamoto, H. Miyagi, H. Kihara, S. Mitsui) - deals with the possibilities to improve the impact strength of rigid polymers via their blending with other polymers. The last part of the book - RECENT DEVELOPMENTS - contains four chapters dedicated to some recent results obtained in the field of polymer blends (Chapter 21. New Strategies for the Tailoring of High-Performance Multiphase Polymer-Based Materials, by Ph. Teyssie; Chapter 22. Developments in Reactive Blending, by Yasuhisa Tsukahara, Hanafi Ismail, Gabriel O. Shonaike; Chapter 23. Developments in Poly(vinyl chloride)/Epoxidized Natural Rubber Blends, by Umaru Semo Ishiaku and Zainal Arifin Mohd Ishak; Chapter 24. Developments of Oil Palm-Based Lignocellulose Polymer Blends, by H. J. Din Rozman and Wan Rosli Wan Daud). Abundantly referenced and illustrated, this comprehensive resource includes more than 1800 drawing, photographs, tables, and bibliographic citations. The book "Polymer Blends and Alloys" provides invaluable information for materials scientist, polymer scientists and engineers, plastic engineers and technologists, physicists, chemists, and upper-level undergraduate and graduate students in these disciplines. Professor Mihai RUSU, Ph.D. |
| The purpose of this book is to review the current status
of high performance polymers, in particular polyimides, in the electronic
industry. Last years, high performance adhesives, composites, coatings, films, fibers, and foams are commercially available for the aerospace, automotive, electrical and electronic industries. The majority of these materials are based on polyimide macromolecules. The first chapter deals with the principal applications of organic polymers in electronics: optical lithography, encapsulation and packaging, conductive adhesives, flexible circuitry, conformal coatings, buffer coatings and interlayer dielectric films, liquid crystal display devices. Chapter 2 presents the specific requirements of the electronic industry. Thus, low molecular weight polyimidic oligomers are used as binders in the production of heat resistent die attach adhesives and thick planarizing layers. The other class includes the high molecular weight polymers exhibiting optimum mechanical properties. An important consideration in the design of new polyimides is to determine the effects of monomer and polymer chemical structures on properties such as adhesion, interfacial stresses, water permeability, dielectric and optical characteristics. Chapter 3 provides some information on the deposition techniques, polyimide cure and etching methods. The adhesive strength, thermal expansion, mechanical stresses and electrical properties are correlated to chemical structure. Polyimides are used in microelectronics either in the form of very thin films, for example as dielectrics in multilevel metallization, or as thicker films in the case of buffer coatings or ? - ray barriers. Due to practical advantages, in the chapter 4, a serious interest is manifested for negative and positive photosensitive polyimides because of the exceptional development of these polymers as buffer coatings and interlayer dielectric. The simple photoresist compositions of polyamic acids or preimidized polymers with acrylic monomers or diazonaphtoquinones, and more sophisticated polyimides incorporating carbon - carbon double bonds either as pendent side groups or as linking units of the main macromolecular backbone are considered very special materials. |
Another chapter is focused on the spin coating process and the theoretical models. Experimental data illustrate the effects of spin speed, solute concentration, molecular weight and solvent evaporation on the final film thickness. The different semi - empirical models were proposed in the literature. Solutions to achieve the best planarity are not obvious because they concern both the materials and the coating techniques. The planarization properties of polyimides films make these polymers particularly attractive as intermetallic insulators in multilayer structures. The chapter treating these problems contains many factors which influence the degree of planarization (polymer characteristics, solution properties, cure cycle and geometry of the underlying topography). Some parameters are incorporated in analytical models. These can be used to establish the degree of planarization with a given polyimide. Alignment layers for liquid crystal display devices constitute now an extremely active area of research, development and production of new polyimides. In chapter 7, the information is restricted to display devices using the electrooptical properties of liquid crystals, and are focused on the chemistry, anisotropy, and electrooptic effects of these materials. The literature data show that changing the polyimide structure and mastering the rubbing process can improve the alignment properties. Among the principal applications of poyimides, the fabrication of multichip modules, polyimide waveguides, non - linear optical components, microsensors and miroactuators are reviewed in relation to polyimide chemistry and process flow. These applications are the main topics of chapter 8. By incorporating a serious volume of data obtained on polyimides in electronics ( high - performance polymers ) this is a very interesting reference book for materials scientists, polymer chemists, manufacturers of electronic and process engineers. Professor Maria IVANOIU, Ph. D. |
| For the past four decades, the use of plastic materials has
continuously increased, but, unfortunately, the education institutions have
not responded in a responsible manner. The manufacturers of durable products
try to improve their efficiency in order to compete and survive in a global
economy. Numerous management procedures have been tried, one of them proved
to be effective, being "Design for Manufacturability and Assembly"
(DFMA). "Designing Plastics Parts for Assembly" is an engineer's handbook on both parts design and assembly . It assembles in a very readable form, a summary of the basic design principles learned over the years regarding plastic parts assembly. The first chapter provides a good review of the fundamental principles of plastic materials, which a good design engineer must understand in order to produce efficient plastic parts assemblies. The second chapter presents the basic resins and their structures, the additives, the main properties of polymers (physical, mechanical, thermal ones). The strength of materials for plastics is discussed in the 3th chapter (tensile strength, compressive stress, shear stress, torsion stress, elongations, Poisson's ratio, modulus of elasticity, stress relations). For every mechanical property discussed, the method, the shape of sample, the definition equations are presented. One concludes that the preferred procedures of quick calculations are ultimate normal stress and ultimate shear stress. The polymers are nonlinear materials, which exhibit viscoelastic properties. They have a dual behavior, showing both elastic and plastic deformations when subjected to an external load. Some nonlinear considerations are presented in chapter 4. |
Chapter 5 deals with the assembly techniques for plastics.
There are two categories of methods for assembling plastics parts. Welding
methods, requiring no additional materials, include ultrasonic welding,
ultrasonic heat staking, hot plate welding, spin welding and vibration welding.
Bonding methods include solvent and adhesive bonding, radio frequency bonding
and electromagnetic bonding, and require the use of an additional adhesive
or bonding agent. Depending on the application, conditions under which the
product will be used, materials and design, it is possible to assemble plastic
parts by one of this method. Chapter 6 discusses the press fitting, a method, which can be used to join components made from the same, or different materials. The theory of press fits, the design algorithm and some examples are presented. Some designs, using flexural soft materials are commonly referred to as living hinges. As an example, polypropylene and polyethylene can flex a million cycles before failure; all other plastics only flex up to a few thousand times. Chapter 7 presents a series of methods available to design and product engineers for use in living flex design, as well as a computer flow chart that facilitates calculations of living hinge design. The last chapter deals with snap fitting, a simple assembly method that joins two parts without using any additional components or fasteners. This method can be used to assemble power tools, computer case, electronic components, packaging boxes, toys, automotive parts, medical devices and thousand of other products. The chapter looks closely at three snap fit families; present ways of selecting material, review geometry and perform detailed design analysis. The 4th edition of Paul Tres' book is an excellent blend of the always important basics and the latest in plastic design technology. It provides a reference for students, designers, product managers, project engineers, research engineers, material engineers or anyone involved in the development and manufacture of plastic products. That is why I warmly recommend it. Professor Marcel POPA, Ph. D. |
| The book is intended to provide a basic understanding of plastic
packaging materials. It covers the properties of common packaging plastics
and relates these properties to the chemical structure of polymers. Common
processing methods for transforming plastic resins into packages are covered. Chapter 1 presents a short historic note, regarding the usage of plastics in packaging, regarding the appearance dates of some basic polymers and also, regarding the development of plastics in packaging. Chapter 2 provides some introductory concepts and definitions. This chapter is intended to remind the reader some basic knowledge in polymer science, such as: terminology, nomenclature, some basic polymer physics notions and a very brief categorization of plastics. Chapter 3 looks at the relationship between chemical and physical structure and properties of plastics. In this chapter, information about molecular architectures, copolymer structure and bloccopolymer synthesis, chain polymerization and addition polymers, molecular configuration and conformation, step polymerization and condensation polymers, molecular weight and polydispersity, polymer morphology, mechanical properties of polymers, optical characteristics, electrical properties are presented. Chapter 4 provides a description of the plastics commonly used in packaging. It begins with the description of some branched polyethylenes and copolymers, and continues with the description of some linear polyethylenes. Then, polypropylene is presented (homo and copolymers). Poly(vinyl chloride) is a very important plastic used in packaging and it is briefly presented, followed by vinylidene chloride copolymers and polystyrene. Another polymer largely used in the packaging is the poly(vinyl alcohol) and its copolymers; this concludes the class of vinyl polymers. Then nylons, polyesters and polycarbonates are presented, but not so largely used, such as fluoropolymers, styrene-butadiene copolymers, acrylonitrile copolymers, liquid crystal polymers, conductive polymers, thermoplastic elastomers, thermosets, cellophane and cellulosic plastics, polymer blends. Chapter 5 looks at other ingredients that go into a plastic resin, such as: antioxidants, heat stabilizers, UV stabilizers, additives to modify surface attractions, colorants, antifogging agents, nucleating agents, antistatic agents, plasticizers, oxygen scavengers, desiccants and fragrance enhancers, fillers and reinforcing materials, antimicrobials and biocides. Chapter 6 examines adhesion, adhesives and heat-sealing, and also sealing methods. After a short classification of adhesives, the most important additives involved in adhesion formulations as well as the application of adhesives are presented. The chapter ends with an evaluation of sealing in flexible packaging materials, the most important ones being tensile testing. Chapter 7 deals with the conversion of plastic resins into film and sheet forms, through a number of methods, such as: extrusion, film and sheet casting, blown film, stretch and shrink wrap, film and sheet coextrusion, surface treatment, yield of film, testing and evaluation of films. The importance of polymer surface preparation is underlined, to ensure a good adhesion; some methods of surface treatment of polymers are also mentioned. Some tests available for determining film quality are shortly presented at the end of this chapter. Chapter 8 examines how film and sheet can be modified by lamination and by coating. The main methods for obtaining the multilayer flexible structures, particularly metallized and silicon oxide ones, are discussed. |
Finally, it is mentioned that the equipment that a supplier
has available will affect the type of materials offered; the decisive factor
should be based on the needs of the product and the packaging machinery
available. In chapter 9, various types of flexible packaging are discussed, and chapter 10 examines thermoforming. Their advantages as compared with rigid packaging, and some possibilities of their obtaining are presented. Since thermoforming is a low pressure forming technique, less expensive materials are required for the molds and less robust equipment is needed to form parts. The three basic steps of thermoforming are presented (heating the sheet, forming the sheet and trimming the part), as well as some fundamental science underlining these steps. Chapter 11 discusses injection molding, rotational molding and compression molding of plastics, with a special look at closures and tubes. Chapter 12 looks at formation of plastics into bottles and other containers by blow molding. The author presents the main technologies for bottles obtaining from different polymer materials. A special attention is paid to the surface treatment of packaging, used for improving barrier properties or for enhancing printability or label adhesion (flame treatment, coating, fluorination, sulfonation). Chapter 13 presents the distribution packaging with an emphasis on foams and cushioning. Plastic pallets, plastic drums and other shipping containers, packaging for electrostatic discharge protection are also briefly discussed. Chapter 14 looks at the barrier characteristics of packaging and how they relate to the shelf life of products. The types of product package interactions that can occur between the plastic material and the product, as well as the factors that affect the sorbtion, diffusion and permeability behavior of polymers are explored. The manners in which polymer and product mass transfer characteristics can be used to predict product shelf life, based on moisture and oxygen transport, are examined. In chapter 15, various laws and regulations regarding packaging choices are discussed. Most of these regulations are not directly aimed at plastic packaging, but rather are parts of more broad-based requirements relating to work place safety, pollution prevention, product labeling, tamper evidence and a variety of other concerns. Finally, chapter 16 examines environmental issues associated with plastic packaging. Reaching of plastics packaging, especially concerning poly(ethylene terephthalate), high-density polyethylene, low-density polyethylene, polystyrene, polypropilene, poly(vinyl chloride) is discussed. A special attention is paid to the biodegradable plastics (polyesters, starch derivatives, lactic acid derivatives) and to the manner in which the pollution and climate change of the planet can be prevented. Even throughout the last years many books concerning plastics packaging have appeared, this one stands out by its unitary character, despite the variety of problems analyzed. The book is the result of more than 50 years of packaging education and research at the Michigan State University, School of Packaging, from the USA. A special merit of the book is the fact that every chapter contains numerical application at the end with some questions to which the reader must answer. The book addresses to the specialists and to all those now preparing to become specialists in the field, but is also very useful for those involved in the field of polymer physical-chemistry and engineering. That is why I warmly recommended it. Professor Marcel POPA, Ph. D. |
| Polymers utilization in all domains of technique is, beyond
any doubt, a reality of our times and the specialists appreciate that polymeric
materials are the "materials of the future". The polymers, as
resulted from synthesis, must be considered as raw materials; their transformation
in final products imposes the association with many other compounds known
as additives. The purpose of the book is to bring up the art and science of modifying polymers through the use of additives. The 13 chapters of this volume, written by reputed specialist, allow to the reader to find diverse approaches to the matter. Ways of modifying the pure individual materials by means of additives to achieve certain results are discussed. From this point of view, the additives can be classified such as: - essential additives for fabrication of parts, - additives which improve some properties, - additives which correct problems caused by other additives. The first class of additives is represented by the antioxidants, being treated in the first chapter. The mechanism of polymers oxidation, the consequences of the oxidation on the polymer structure and properties and the way in which the antioxidant acts for limiting the effects of oxidation are well known. The primary antioxidants (phenols) and the secondary ones (amines, metal deactivators, UV absorbers, quenchers) as well as their action mechanisms are presented. The chapter ends with the presentation of the selection criteria and some applications of antioxidants on polyolephines, vinyl polymers and condensation polymers. A desirable feature for marketability and identification is the color of plastics. The colorants (dyes, which are soluble in plastics and pigments, which are slightly soluble or insoluble) are treated in chapter 2. Dyes are finding special uses where they can be incorporated into formula in very low concentration, but they present some disadvantages. A special attention is paid to the pigments; the author presents their classification, properties and characteristics, special problems arising during polymeric material usage. Some factors affecting the colorants (thermal and UV stabilities, migration resistance by polymeric matrix, blooming, weatherability) are presented at the end. The obtaining of polymer matrix composites permits to achieve high-tech materials by association of macromolecular compounds with fillers or reinforcing materials. To ensure a good adhesion between the components, the surface treating of the latter is necessary. The chapters 3,4,5 discuss these aspects. The mechanism of interaction between the coupling agents and fillers or reinforcements, as well as with the polymer matrix is presented in chapter 3. Chapter 4 focuses on glass fiber reinforcements, presenting the main fibers used to this end, the selection criteria for a certain polymer matrix, their characteristics ensuring a very good reinforcement, the methods for obtaining reinforced thermoplastics. A more special attention is paid to fillers, which can be in the form of solid, liquid or gas. Chapter 5 presents the classification of the fillers, their chemistry, properties and performance, the analytical methods and filler quality control. The thermal properties of polymeric materials are very important for the most applications. Chapter 6 deals with the flame-retardant and smoke suppressants. Flame-retardant mechanism and tests, as well as flame retardant additives and smoke suppressants are presented. |
The effect of flame-retardant utilization for some thermoplastic
polymers [polypropylene, polyethylene, polystyrene, poly(styrene-co-acrylonitrile),
poly(styrene-co-acrylonitrile-co-butadiene), poly(ethylene oxide), polycarbonate,
poly(butylene terephthalate), poly(ethylene terephthalete), polyamides,
poly(methyl methacrylate) poly(vinyl chloride) and PVC based alloys, epoxy
resins, unsaturated polyesters, polyurethanes] are discussed and illustrated
by very suggestive diagrams. The thermal stabilization of halogenated polymers, particularly of poly(vinyl chloride) are largely presented in chapter 7. Many thermoplastic polymers present a low impact resistance, imposed by their chemical structure [polystyrene, poly(methyl methacrylate)], a fact which reduces their usage in technique. Chapter 8 presents the types of impact modifiers and the methods for testing the impact strength. Application of additive impact modifiers in toughened plastics is presented in the end of this chapter. In order to facilitate the polymer processing, one may use the lubricants, which are substances that, when added in small quantities, provide a considerable decrease in resistance to the movement of chains or segments of a polymer. Analysis and selection of lubricants and specific lubricants are presented in chapter 9. The optical brighteners, which are used to improve the yellowship appearance of "white" products, mainly textiles, are discussed in chapter 10. The mechanism of optical brightening, the use of optical brighteners in plastics, the compatibility with other additives and the current usage in plastics [polyolephins, poly(vinyl chloride), polyamides, polyurethanes, polycarbonates, cellulosic, polyacetals and other polymers] are examined. In order to impart flexibility, extensibility and/or processability of some tough and hard thermoplastics, plasticizers are used. Chapter 11 discusses the plasticizers requirements (compatibility, permanence, efficiency), structure and properties of plasticizers, applications and health concerns. Some starting formulations for poly(vinyl chloride) applications are presented at the end of this chapter. Other methods of enhancing processing by reducing melt viscosity and temperature include the addition of low-molecular weight species of the same polymers, known as "processing aids". Chapter 12 deals with processing aids for poly(vinyl chloride), discussing their mechanism of operation and effects on the rheology of PVC melts, the latter being suggestively illustrated by diagrams and photomicrographs. Special additives are treated in the last chapter: antiblocking agents and slip additives, antistatic agents, foaming agents, foam promoters and accelerators, fungicited, bactericides and other biocides, reodorants. The mechanism of their action, methods of incorporation, test methods are briefly discussed for every type of compound. The book now reviewed is not unique in the field of polymer additives, but has the special quality to unify, in a single volume, the quasitotality of polymer modifiers and additives. The reader can find, treated in very clear and concise manner, both the fundamental theoretical aspects and the applicative ones concerning the use of these additives for polymer materials obtaining. I think this book must exist in all libraries of universities, research institutes and companies where specialist in polymer materials science work. I warmly recommend this book to students and researchers involved in this field. Professor Marcel POPA, Ph. D. |
| Polymer usage in all technical domains has been a reality
for decades. The researchers efforts to expand polymeric materials usage
areas are justified by the necessity of developing new materials with special
characteristics, especially hi-tech materials used in aeronautic and aerospace
technology, electrical engineering and electronics. Undoubtedly, polymeric
composite materials are unanimously considered as materials of the future
by all researchers. The polymer composite materials obtaining is, on the other hand, very complex, requiring vast knowledge in polymer chemistry and physics, rheology, kinetics, transport and transfer phenomena, mechanics and system control. The book represents a review of the basic principles of polymer composite processing, of the most important processes concerning their obtaining. Its authors are prestigious specialists from universities, research institutes, chemical companies in the USA, Europe and Asia. The book is structured in two parts: - theory - processes. The first chapter of the first part discusses some aspects concerning kinetics and chemistry of the synthesis of some thermoplastic polymers by ring opening polymerisation, particularly on caprolactam. The authors present a model of the raising of the polymer's viscosity during the anionic polymerisation of the caprolactam, which they use with good results to the obtaining of composites with polyamide 6 matrix reinforced with glass fibres, by reaction injection pultrusion. The second chapter relates to some rheological and kinetic aspects concerning the curing of thermoreactive polymers. The authors present the equations used for the description of some interdependent phenomena, such as the flow of the polymer, the heat transfer, crosslinking reactions which are unavoidable phenomena in such processing processes. At the end of the chapter. the authors introduce some strategies for optimizing and controlling the processes, in order to obtain optimum crosslinking cycles. The 3rd chapter analyses aspects concerning morphology changes and phase separations during the crosslinking reaction of some polyeter-imides, emphasizing the mechanisms, analysed through the thermodynamic and kinetic point of view. Chapter 4 describes a new technique of monitoring in situ of macroscopic cure processing properties and the reaction advance in the fabrication tool; it is discussed the in situ frequency dependent electromagnetic-impedance measurements. The process' theory is discussed, and some applications of this technique are presented. A very interesting approach to modeling, in a unitary system, the transport of heat, mass and momentum in the processing of polymer matrix composite materials is presented in chapter 5. Starting from the mass balance, the author obtains some specialized equations for the processing of different polymer composites by resin transfer moulding (RTM), injected pultrusion (IP) and autoclave processing (AP). The method is advantageous because it allows a very precise definition of the average temperature, velocity and pressure in processing of some porous media which are in a movement or in a stationary regime. Very close to this chapter is the next one, which presents a model concerning the stability, growth and transport of holes during the polymer composite processing. The model is developed for the autoclave processing, but his concept and related equations can be applied in a large variety of processing, too (RM, CM and filament winding). Chapter 7 is related to the modeling and consolidation during thermoplastic composite processing. It discusses the effects of the processing cycle on the mechanisms of an intimate contact between the thermoplastic matrix and the reinforcing material, occurring in the case of autoadhesive bonding. The analysis is based on theories which explain the development of the strong polymer-polymer interface and the fracture of polymers; in the same time they establish a mathematical relation between the bonds formation at the interface of the composite components, time and processing temperature. |
The raising of residual stresses in composite materials is
inherent, due to the different behaviour of the components, when subjected
to thermal solicitation during the curing. Chapter 8 treats the modeling
of this residual stresses and the influence of processing (curing and postcuring
temperatures) on them. The presented methodology is generic and can be applied
to other types of materials and processing methods, but, in all cases, it
implies a characterization of the cure state. The last chapter of the first part treats the intelligent control of product quality in polymer composite manufacturing. The evolution of these intelligent processing strategies and the current research in this field are related. The presented models are really very useful for the practice, especially in the case of autoclave curing, where more complex problems than for the traditional chemical processing are implied. The second part of the book is related to the polymer composite processing, which are presented in 6 chapters. The first of them discusses the autoclave processing, used for fabricating of the continuous fiber-reinforced thermoset composite parts. It provides an overview and reference guide for the fundamental understanding of autoclave processing. Chapter 11 presents the pultrusion process, which is - from a scientific point of view - relatively poor understood process, despite the fact that it is a very economic and largely used process. The process description, the equipment, the process modeling - which is then experimentally verified on some examples - are presented. The principles of liquid composite molding (LCM) are presented in chapter 12. This class of manufacturing processes has the common feature that in the mold cavity of the form filled with dry reinforcement the liquid resin is injected (resin transfer molding, structural reaction injection molding). Each strategy of injection is described and illustrated with examples, and a relevant theory for polymer curing in forms is presented. The next chapter is related to the filament winding, which is applied both for the obtaining of closed-surface composite structures (cylindrical and spherical ones) as well as for nonsymetric parts with complex curvature. The method and equipment, the models, which simulate de process and the characterization of wound parts obtained by this technique, are presented. Dieless forming of thermoplastic matrix composites is discussed in the 14th chapter. This method is applied to form components with arbitrary and variable curvature, based on continuous fiber-reinforced composites. The author conceived an approach to the forming of more complex shapes from thermoplastic matrix, which takes advantage of the continuous fibers, that is, usually, an impediment in many other processes to flaw-free forming. The last chapter is devoted to the presentation of some intelligent processing tools for composite processing. Both advantages and disadvantages of each method (injection molding, resin transfer molding, autoclave curing) are discussed. The fact that a control system for polymer manufacturing must have some capabilities (a logical sequence of events, dynamic interactions between control and quality, detect and react to failure conditions, provide predictions of process trends and/or outcomes etc.) is underlined. In the last years many studies, monographs etc. - devoted to composite
processing - have been issued. The book now reviewed, based on the most
recent investigations developed in the whole world, opens new and promising
perspectives in this incitation zone of materials science, with immediate
consequences in the technique development. Professor Marcel POPA, Ph. D. |