1st Edition
Thermotropic Liquid Crystal Polymers Thin-film Poly Chara Blends
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.
Preface
INTRODUCTION OF LIQUID CRYSTALLINE MATERIALS
History of development of liquid crystalline materials
Classification and structure of liquid crystalline materials: Classification and structure of LCs, Classification and structure of LCPs
Liquid crystal textures: Textures of Neumatic LCs, Texture of smectic LCs, Texture of cholesteric LCs
Theories of liquid crystal state: Theories of nematic LCs, Theories of LCPs
Main-chain liquid crystalline polymers: Research focus of thermotropic main-chain LCPs, Chemical structures of main-chain LCPs, Synthesis of main-chain LCPs, End-use properties and applications of main-chain LCPs
INVESTIGATION AND SYNTHESIS OF LIQUID CRYSTALLINE POLYMERS BY THIN FILM POLYMERIZATION
Introduction
Experimental detail of thin film polymerization
Morphological changes during thin film polymerization of liquid crystalline polymers: Generation of the liquid crystal phase, Annihilation of disclinations
Formation of banded texture
Investigation of the effects of reaction conditions on the synthesis of liquid crystalline polymers: Effects of reaction temperature on the thin film polymerization, Effects of catalyst on the thin film polymerization
Investigation of the formation of liquid crystallinity: Effects of monomer structures on liquid crystallinity, Effects of reaction temperatures on the liquid crystallinity
Investigation of the electric response of liquid crystalline polymer during polymerization: Introduction of the electric field effects on liquid crystalline materials, Polymerization of liquid crystalline polymer under electric field, Electric response of the polymerization system of liquid crystal polymer
CRYSTALLIZATION OF MAIN CHAIN LIQUID CRYSTALLINE POLYMERS
Introduction
Polymer Crystallization: Theory : Isothermal crystallization, Non-isothermal crystallization, Crystallinity determination
Main chain LCP crystallization: Liquid crystalline polyimides, Poly(amide-imide), Crystallization of thermotropic liquid crystalline polyesters
THE THERMAL STABILITY AND DEGRADATION BEHAVIOR OF THERMOTROPIC LIQUID CRYSTALLINE POLYMERS
Introduction
Thermal Stability and Degradation Mechanisms: Commercial TLCPs, Other TLCPs
Thermal Degradation Kinetics: Background of Degradation Kinetic Modeling, Analysis Results
X-RAY SCATTERING FROM LIQUID CRYSTALLINE POLYMERS
Introduction
Numerical simulation of x-ray diffraction patterns of nematic systems: A packing model for the nematic systems-parallel packed hard rods, X-Ray scattering from a dilute system of parallel packed hard rods, Interference among the rods
Numerical simulation of X-Ray Diffraction patterns of smectic systems
Monodomain and polydomain structures
X-Ray scattering from unoriented liquid crystalline polymers-powder diffraction method
X-Ray scattering from oriented liquid crystalline polymers-fiber scattering
Summary
Appendix
SURFACE TENSION INVESTIGATIONS OF THERMOTROPIC LIQUID CRYSTALLINE POLYMER
Introduction
Estimation of Surface Tension of a Solid: Contact angle and the Young's equation, Zisman's method, Neumann's method, Fowkes' method, Owens, Wendt, and Kaeblle's method, Wu's method, Lifshitz method, Theoretical estimation from group contribution hypothesis
Surface tension of commercial thermotropic liquid crystalline polymers: Polymer materials, Spin-coating LCP films, Contact angle measurement, Results and discussions, Theoretical estimation by group contributions method
Surface tension evolution during thin film polymerization: Background, Experiments, Results and discussion
LCP BLENDS
Introduction
In-situ composites: Fibrillation, Compatibilization, Mechanical performance of in-situ composites
In-situ hybrid composites: Concept and model of in-situ hybrid composites, Hybrid effect in in-situ hybrid composites
RHEOLOGY AND PROCESSING OF THERMOTROPIC LIQUID CRYSTALLINE POLYMERS
Introduction
Molecular dimension of thermotropic liquid crystalline polymers
Dynamics of liquid crystalline polymers
Rheology of thermotropic liquid Crystalline polymers: Three region flow, Dynamic melt viscosity, Effects of molecular weight, Effects of temperature, Effects of glass fibers, Negative normal stress difference, Elongational viscosity, Die swell
Processing of Thermotropic Liquid Crystalline Polymers: Injection molding, Extrusion and compounding, Fiber spinning
LIQUID CRYSTAL ELASTOMERS, NETWORKS, AND GELS
Introduction
Liquid crystalline elastomers (LCEs): Synthesis and phase behavior, Physics properties, LC thermal-plastic elastomers
Liquid single crystal elastomers, Anisotropic networks, and gels: Concept for LSCE, Synthesis and characterization of LSCE, anisotropic networks and gels, Coupling effect between mesogen and polymer network, Memory effect of LC networks, Specific Anisotropic network systems
THERMOSETTING LIQUID CRYSTAL POLYMERS
Introduction
Synthesis and phase behavior of thermosetting LC polymers: Epoxy rigid and semi-rigid rod network, Cyanate ester rigid rod network, Bismaleimide rigid network, Diacrylate semi-rigid rod network, Bisacetylene rigid rod network, Rigid and semi-rigid network based on hybrid organic-inorganic designs
Reaction kinetics of LC-thermosets
Physical properties and potential application
LCP EXTRUSION AND APPLICATIONS
Introduction
LCP background: Conventional extrusion of LCP, Controlled orientation of LCP film
Counter-rotating dies for extrusion: Orientation in LCP film, Calculation of orientation angles, Multilayer coextrusion
Tube extrusion and applications: Applications and properties of LCP tube, Processing and performance of LCP tubing, Medical applications of LCP tubing, Other applications of LCP tube
Film extrusion and applications: The LCP blown film process, LCP film in printed circuit boards, LCP film in high barrier packaging applications
Blow molding in LCPs and applications
LCP-thermoplastic blends and alloys, processing and applications: Tensile properties of LCP blends, Processing LCP blends and alloys
Conclusions
Index
195 figures
60 tables
MICROGRAPHS, PHOTOGRAPHS, DIAGRAMS, FLOWCHARTS AND OTHER SCHEMATICS - a total of 195 -- illustrate materials, processes and applications. Here is a small sampling of these graphics. o Micrographs (series of 20) showing morphologies of 73/27 ABA/ANA polymerization reaction system at different reaction times o Schematics of two-step polymerization of polyimide o Repeating unit structures of commercial LCPs o Schematic representation of different types of LC elastomers (LCE) from side chain, main chaintype, and combined main chain/side group type…o Schematic of mechanical behavior of LC elastomers o Chemical route to a macroscopically oriented LC network o Scanning electron micrograph of a gel obtained after the extraction of the non-reactive LC o Rigid rod epoxy thermoset monomers o Non-equilibrium phase diagram describing the behavior of liquid crystalline thermosets o Effect of rotation rate on orientation (film) o Schematic representation of coextruded LCP-thermoplastic multiplayer
TABLES
Sixty tables provide extensive data useful in R&D. Here is a small sampling of this material. o The effect of reaction temperature on the transition time of morphological changes o Reference data for reaction rate constants obtained from uncatalyzed bulk polymerization reactions o Some liquid crystalline polyimides (structures) o The morphology in polyblends containing LCPs reported in the literature o Various third components acting as compatibilizers and the compatibilized in situ composites o The mechanical properties of in situ composites (including processing method) o Properties of thermotropic LCP films
