INTRODUCTION TO PHYSICAL POLYMER SCIENCE

Transcription

1 INTRODUCTION TO PHYSICAL POLYMER SCIENCE THIRD EDITION L. H. Sperling Lehigh University Bethlehem, Pennsylvania WILEY- INTERSCIENCE A John Wiley & Sons, Inc., Publication New York Chichester Weinheim Brisbane Singapore Toronto

2 CONTENTS Preface Preface to the Second Edition Preface to the First Edition Symbols and Definitions xxv xxvii xxix xxxi 1 Introduction to Polymer Science From Little Molecules to Big Molecules / Molecular Weight and Molecular Weight Distributions / Effect on Tensile Strength / Molecular Weight Averages / Major Polymer Transitions / Polymer Synthesis and Structure / Chain Polymerization / Free Radical Polymerization j Initiation / Propagation / Termination / Structure and Nomenclature / Step Polymerization / A Polyester Condensation Reaction / Stepwise Nomenclature and Structures / Natural Product Polymers / Cross-Linking, Plasticizers, and Fillers / The Macromolecular Hypothesis / Historical Development of Industrial Polymers / Molecular Engineering / 19 References / 19 General Reading / 20 vii

3 CONTENTS Handbooks, Encyclopedias, and Dictionaries / 21 Web Sites / 21 Study Problems / 22 Appendix 1.1 Names for Polymers / 23 Chain Structure and Configuration 2.1 Examples of Configurations and Conformations / Head-to-Head and Head-to-Tail Configurations / Trans-Gauche Conformations / Theory and Instruments / Chemical Methods of Determining Microstructure / General Physical Methods / Infrared and Raman Spectroscopic Characterization / Nuclear Magnetic Resonance Methods / Stereochemistry of Repeating Units / Chiral Centers / Tacticity in Polymers / Meso- and Racemic Placements / Proton Spectra by NMR / Repeating Unit Isomerism / Optical Isomerism / Geometrie Isomerism / Substitutional Isomerism / Infrared and Raman Spectroscopic Characterization / Common Types of Copolymers / Unspecified Copolymers / Statistical Copolymers / Random Copolymers / Alternating Copolymers / Periodic Copolymers / NMR in Modern Research / Dilute Solution Studies: Mer Distribution / High-Resolution NMR in the Solid State / Multicomponent Polymers / Block Copolymers / Graft Copolymers / AB-Cross-linked Copolymer / Interpenetrating Polymer Networks / Other Polymer-Polymer Combinations / Separation and Identification of Multicomponent Polymers / 48

4 2.8 Conformational States in Polymers / Analysis of Polymers during Mechanical Strain / Photophysics of Polymers / Quenching Phenomena / Excimer Formation / Experimental Studies / Microstructure of Polystyrene / Excimer Stability / Configuration and Conformation / 56 References / 57 General Reading / 58 Study Problems / 58 Appendix 2.1 Assorted Isomeric and Copolymer Macromolecules / 60 Molecular Weights and Sizes 3.1 Introduction / Polymer Size and Shape / How Does a Polymer Dissolve? / The Solubility Parameter / Solubility Parameter Tables / Experimental Determination / Theoretical Calculation: An Example / Thermodynamics of Mixing / Types of Solutions / The Ideal Solution / Statistical Thermodynamics of Mixing / Other Types of Solutions / Dilute Solutions / Values for the Flory-Huggins X\ Parameter / A Worked Example for the Free Energy of Mixing / Molecular Weight Averages / Determination of the Number-Average Molecular Weight / End-Group Analyses / Colligative Properties / Osmotic Pressure / Thermodynamic Basis j Instrumentation / The Flory O-Temperature / Weight-Average Molecular Weights and Radii of Gyration / Scattering Theory and Formulations / 82

5 X CONTENTS The Appropriate Angular Range / The Zimm Plot / Polymer Chain Dimensions / Scattering Data / Dynamic Light-Scattering / Molecular Weights of Polymers / Molecular Weight of Commercial Polymers / Thermodynamics and Kinetics of Polymerization / Thermodynamics of Chain Polymerization / Kinetics of Chain Polymerization / Thermodynamics of Step Polymerization / Kinetics of Step Polymerizations / Molecular Weight Distributions / Gelation and Network Formation / Intrinsic Viscosity / Definition of Terms / The Equivalent Sphere Model / The Mark-Houwink Relationship / intrinsic Viscosity Experiments / Example Calculation Involving Intrinsic Viscosity / Gel Permeation Chromatography / Theory of Gel Permeation Chromatography / Utilization of Distribution Coefficients of GPC and HPLC / Types of Chromatography / GPC Instrumentation / Calibration / Selected Current Research Problems / The Universal Calibration / Mass Spectrometry / Solution Thermodynamics and Molecular Weights / 115 References / 116 General Reading / 119 Study Problems / 119 Appendix 3.1 Calibration and Application of Light-Scattering Instrumentation for the Case Where P(0) = 1 / Concentrated Solutions and Phase Separation Behavior Phase Separation and Fractionation / Motor Oil Viscosity Example / 123

6 CONTENTS Xi Polymer-Solvent Systems / Vitrification Effects / Regions of the Polymer-Solvent Phase Diagram / Polymer-Polymer Phase Separation / Phase Diagrams / Thermodynamics of Phase Separation / An Example Calculation: Molecular Weight Miscibility Limit / Equation of State Theories / Kinetics of Phase Separation / Miscibility in Statistical Copolymer Blends / Polymer Blend Characterization / Graft Copolymers and IPNs / Block Copolymers / Example Calculations with Block Copolymers / Ionomers / Diffusion and Permeability in Polymers / Swelling Phenomena / Fick's Laws / Permeability Units / Permeability Data / Effect of Permeant Size / Permselectivity of Polymerie Membranes and Separations / Types of Membranes / Gas Separations / Latexes and Suspensions / Natural Rubber Latex / Colloidal Stability and Film Formation / Multicomponent and Multiphased Materials / 156 References / 157 General Reading / 159 Study Problems / 160 Appendix 4.1 Scaling Law Theories and Applications / The Amorphous State The Amorphous Polymer State / Solids and Liquids / Possible Residual Order in Amorphous Polymers? / Experimental Evidence Regarding Amorphous Polymers / Short-Range Interactions in Amorphous Polymers / Long-Range Interactions in Amorphous Polymers / Small-Angle Neutron Scattering / 170

7 CONTENTS Electron and X-Ray Diffraction / General Properties / Conformation of the Polymer Chain / Models and Ideas / The Freely Jointed Chain / Kuhn Segments / The Random Coil / Models of Polymer Chams in the Bulk Amorphous State / Macromolecular Dynamics / The Rouse-Bueche Theory / Reptation and Chain Motion / The de Gennes Reptation Theory j Fickian and Non-Fickian Diffusion j Nonlinear Chains / Experimental Methods of Determining Diffusion Coefficients / Concluding Remarks / 190 References / 191 General Reading / 193 Study Problems / 193 Appendix 5.1 Appendix 5.2 Appendix 5.3 History of the Random Coil Model for Polymer Chains / 195 Calculations Using the Diffusion Coefficient / 198 Nobel Prize Winners in Polymer Science and Engineering / 199 The Crystalline State 6.1 General Considerations / Historical Aspects / Melting Phenomena / Example Calculation of Percent Crystallinity / Methods of Determining Crystal Structure / A Review of Crystal Structure / X-Ray Methods / Electron Diffraction of Single Crystals / Infrared Absorption / Raman Spectra / The Unit Cell of Crystalline Polymers / Polyethylene / 210

8 6.3.2 Other Polyolefin Polymers / Polar Polymers and Hydrogen Bonding / Polymorphie Forms of Cellulose / Principles of Crystal Structure Determination / Structure of Crystalline Polymers / The Fringed Micelle Model / Polymer Single Crystals / The Folded-Chain Model / The Switchboard Model / Crystallization from the Melt / Spherulitic Morphology / Mechanism of Spherulite Formation / Spherulites in Polymer Blends and Block Copolymers / Percent Crystallinity in Polymers / Kinetics of Crystallization / Experimental Observations of Crystallization Kinetics / Theories of Crystallization Kinetics / The Avrami Equation / Keith-Padden Kinetics of Spherulitic Crystallization / Hoffman's Nucleation Theory / Example Calculation of the Fold Surface Free Energy / Three Regimes of Crystallization Kinetics / The Reentry Problem in Lamellae / Infrared Spectroscopy / Carbon-13 NMR / Small-Angle Neutron Scattering / Single-Crystal Studies / Melt-Crystallized Polymers j Extended Chain Crystals / Thermodynamics of Fusion / Theory of Melting Point Depression / Example Calculation of Melting Point Depression / Experimental Thermodynamic Parameters / Entropy of Melting / The Hoffman-Weeks Equilibrium Melting Temperature / Effect of Chemical Structure on the Melting Temperature / Fiber Formation and Structure / X-Ray Fiber Diagrams / 260

9 XIV CONTENTS Natural Fibers / The Hierarchical Structure of Polymerie Materials / How Do You Know It's a Polymer? / 263 References / 265 General Reading / 269 Study Problems / Polymers in the Liquid Crystalline State Definition of a Liquid Crystal / Rod-Shaped Chemical Structures / Liquid Crystalline Mesophases / Mesophase Topologies / Phase Diagrams / First-Order Transitions / Liquid Crystal Classification / Lyotropic Liquid Crystalline Chemical Structures / Thermotropic Liquid Crystalline Chemical Structures / Side-Chain Liquid Crystalline Chemical Structures / Thermodynamics and Phase Diagrams / Historical Aspects / Importance of the/! Parameter / Mesophase Identification in Thermotropic Polymers / Fiber Formation / Viscosity of Lyotropic Solutions / Molecular Orientation / Comparison of Major Polymer Types / Molecular Conformation / Properties in Bulk / Basic Requirements for Liquid Crystal Formation / 292 References / 292 General Reading / 293 Study Problems / Glass-Rubber Transition Behavior Simple Mechanical Relationships / Modulus / Young 's Modulus / Shear Modulus / 297

10 CONTENTS Newton'sLaw / Poisson's Ratio / The Bulk Modulus and Compressibility / Relationships among E, G, B, and v / Compliance versus Modulus / Numerical Values for E / Storage and Loss Moduli / Five Regions of Viscoelastic Behavior / The Glassy Region / The Glass Transition Region / The Rubbery Plateau Region / The Rubbery Flow Region / The Liquid Flow Region / Effect of Plasticizers / Definitions of the Terms "Transition," "Relaxation," and "Dispersion" / Melt Viscosity Relationships Near T g / Dynamic Mechanical Behavior through the Five Regions / Methods of Measuring Transitions in Polymers / Dilatometry Studies / Thermal Methods / Mechanical Methods / Dielectric and Magnetic Methods / A Comparison of the Methods / The Cole-Cole Plot / Other Transitions and Relaxations / The Schatzki Crankshaft Mechanism / Main-Chain Motions / Side-Chain Motions / The T u Transition / Time and Frequency Effects on Relaxation Processes / Time Dependence in Dilatometric Studies / Time Dependence in Mechanical Relaxation Studies / Frequency Effects in Dynamic Experiments / Theories of the Glass Transition / The Free-Volume Theory / T g as an Iso-Free-Volume State / The WLFEquation / An Example of WLF Calculations / The Kinetic Theory of the Glass Transition / Estimations of the Free-Volume Hole Size in Polymers / 331

11 XVI CONTENTS Positron Annihilation Lifetime Spectroscopy / Thermodynamic Theory of T g j The Gibbs and DiMarzio Theory / Effect of Cross-link Density on T g / A Summary oft he Glass Transition Theories / A Unifying Treatment / Effect of Molecular Weight on T g / Linear Polymers / Effect of T g on Polymerization / Effect of Copolymerization on T g / One-Phase Systems / Two-Phase Systems / Effect of Crystallinity on T g / The Glass Transition of Polyethylene / The Nylon Family Glass Transition / Relationships between T g and 7/ / Heat Distortion Temperature / Dependence of T g on Chemical Structure / Effect of Aliphatic Side Groups on T g / Effect of Tacticity on T g / Effect of Pressure on T g / Damping and Dynamic Mechanical Behavior / Defmitions of Elastomers, Plastics, Adhesives, and Fibers / 353 References / 354 General Reading / 358 Study Problems / 358 Appendix 8.1 Molecular Motion near the Glass Transition / Cross-Iinked Polymers and Rubber Elasticity Cross-links and Networks / The Sol-Gel Transition / Micronetworks / Historical Development of Rubber / Early Developments / Twentieth-Century Developments / Rubber Network Structure / Rubber Elasticity Concepts / 369

12 9.5 Thermodynamic Equation of State / Equation of State for Gases / Statistical Thermodynamics of Rubber Elasticity / The Equation of State for a Single Chain / The Equation of State for a Macroscopic Network / Some Example Calculations / An Example of Rubber Elasticity Calculations / An Example of Work Done during Stretching / '.4 Comparison to Metal Springs / The "Carnot Cycle" for Elastomers / The Carnot Cycle for a Gas / The Carnot Cycle for an Elastomer / Work and Efficiency / An Elastomer Thermal Cycle Demonstration / Continuum Theories of Rubber Elasticity / The Mooney-Rivlin Equation / Generalized Strain-Energy Functions / Some Refinements to Rubber Elasticity / The Inverse Langevin Function / Cross-link Functionality / Network Defects / Volume Changes and Swelling / Physical Cross-links / Trapped Entanglements / The Phantom Network j Small-Angle Neutron Scattering / Internal Energy Effects / Thermoelastic Behavior of Rubber / Experimental Values / The Flory-Rehner Equation / Causes of Swelling / Example Calculation of Young's Modulus from Swelling Data / Gelation Phenomena in Polymers / Gelation in Solution / Gelation during Polymerization / Hydrogels / Gels and Gelation / Effects of Strain on the Melting Temperature / 409

13 XVÜi CONTENTS 9.16 Elastomers in Current Use / Classes of Elastomers / Diene Types / Saturated Elastomers / Thermoplastic Elastomers / Inorganic Elastomers / Reinforcing Fillers and Other Additives / Summary of Rubber Elasticity Behavior / 417 References / 418 General Reading / 422 Study Problems / 422 Appendix 9.1 Gelatin as a Physically Cross-linked Elastomer / 424 Appendix 9.2 Elastic Behavior of a Rubber Band / 428 Appendix 9.3 Determination of the Cross-link Density of Rubber by Swelling to Equilibrium / Polymer Viscoelasticity and Rheology Stress Relaxation and Creep / Molecular Bases of Stress Relaxation and Creep / Models for Analyzing Stress Relaxation and Creep / The Maxwell and Kelvin Elements / The Four-Element Model / The Takayanagi Models / Relaxation and Retardation Times / The Relaxation Time / Applications of Relaxation Times to Chemical Reactions / Chemical Stress Relaxation / Procedure X / Continuous and Intermittent Stress Relaxation / The Retardation Time / Dynamic Mechanical Behavior of Springs and Dashpots / Molecular Relaxation Processes / Diffusion at Short Times / Relationships among Molecular Parameters / Example Problem for Polystyrene / Example Problem Relating to Adhesives / Physical Aging in the Glassy State / The Time-Temperature Superposition Principle / 454

14 CONTENTS XIX The Master Curve / The Reduced Frequency Nomograph / Polymer Melt Viscosity / The WLF Constants / The Molecular-Weight Dependence of the Melt Viscosity / Critical Entanglement Chain Length / An Example Calculation of Melt Viscosity / Analysis of Z cw / The Tube Diffusion Coefficient / Polymer Rheology / Shear Dependence of Viscosity / Normal Stress Differences / Dynamic Viscosity / Instruments and Experiments / General Defmitions and Terms / Overview of Viscoelasticity and Rheology / 468 References / 469 General Reading / 471 Study Problems / 471 Appendix 10.1 Energy of Activation from Chemical Stress Relaxation Times / 473 Appendix 10.2 Viscoelasticity of Cheese / Mechanical Behavior of Polymers An Energy Balance for Deformation and Fracture / The First Law of Thermodynamics / Relations for Springs and Dashpots / Deformation and Fracture in Polymers / Stress-Strain Behavior of Polymers / General Behavior / Tensile Strength of Plastics / Time and Temperature Effects / Semicrystalline Polymers / Liquid Crystalline Polymers / Cold Drawing in Crystalline Polymers / The Brittle-Ductile Transition / Impact Resistance / Instrumentation / Toughening by Rubber Addition / Mechanical Behavior of Elastomers / 494

15 CONTENTS Stress-Strain Behavior / Viscoelastic Rupture of Elastomers / Fiber-Reinforced Plastics / Matrix Materials / Silane Interfacial Bonding Agents / Molecular Composites / CrackGrowth / The Griffith Equation / The Stress Intensity Factor / A Worked Example / Cyclic Deformations / Mechanisms of Crack Growth / Fatigue Crack Propagation / Molecular Aspects of Fracture and Healing in Polymers / Interdiffusion at a Polymer-Polymer Interface / Molecular Basis of Fracture in Glassy Plastics / Energy Well Activation / Chain Pullout / Temperature of Chains Being Pulled Out / Molecular Weight Requirements / Scaling Laws for a Polymer-Polymer Interface / Tensile Strength Dependence on Interdiffusion Distance / Summary / 516 References / 517 General Reading / 519 Study Problems / 520 Polymer Surfaces and Interfaces 12.1 Polymer Surfaces / Thermodynamics of Surfaces and Interfaces / Surface Tension / Example Calculation of Surface Tensions / Polymer Blend Interfaces / Crystalline and Glassy Polymers / Instrumental Methods of Characterization / Surface Tension and Contact Angles / ESCA (XPS) / Scanning Electron Microscopy / Scanning Probe Microscopy / Near Atomically Sharp Rasters / 533

16 CONTENTS The Molecular Basis offriction j Elasticity and Modulus Measurements / Secondary Ion Mass Spectrometry, SIMS / Ion Beam Analysis / RBS, FRES, and NRA Instruments j Observation of Block Copolymers at Interfaces / Neutron Reflectometry / The Ripple Experiment / Theoretical Polymer Blend Interphase Thickness / Example Calculation of Interphase Thickness / Experimentally Determined Interphase Thicknesses / Determination of Interior Surface Areas / Theory for X-Ray, Neutron, and Light-Scattering / K 4 Dependence of Interphase Thickness / Conformation of Polymer Chains in a Polymer Blend Interphase / The Dilute Solution-Solid Interface / Nondrip Latex Paint / Conformation of Polymer Chains at Solution Interfaces / Example Calculation of p / Conformation of the Bound Chains with Increasing Solution Concentration / Example Calculation: A Single Chain Bound to Two Colloid Particles / Depletion Zones / Instrumental Methods for Analyzing Polymer Solution Interfaces / The Force Balance Apparatus (Surface Forces Apparatus) / Total Internal Reflectance Fluorescence, TIRF / Brewster Angle Reflectivity / Dynamic Light-Scattering / Theoretical Aspects of the Organization of Chains at Walls / The Self-similarity of Polymer Chains near Walls / Fractionation of Polymer Chains near Walls / Fractal-like Interfaces / Adhesion at Interfaces / Forms of Adhesives / Strength of Adhesion with Cross-linking / 567

17 XXÜ CONTENTS Experimental Measurement of Adhesion Forces / Pressure-Sensitive Adhesives / Surface Modification / Overview of Polymer Surface and Interface Science / 569 References / 571 General Reading / 573 Study Problems / 574 Appendix 12.1 Estimation of Fractal Dimensions / Multicomponent Polymerie Materials Classification Scheines for Multicomponent Polymerie Materials / Combinations of Two Kinds of Mers / Polymer-Based Composites / Miscible and Immiscible Polymer Pairs / The Glass Transition Behavior of Multicomponent Polymer Materials / The Glass Transitions of Polymer Blends / An Example Calculation of Polymer Blend Glass Transition Temperatures / Glass Transitions of Polymer Composites / The Modulus of Multicomponent Polymerie Materials / Moduli of Particulate Composites / Example Calculation of Composite Moduli / Other Mathematical Relationships for Modulus Calculations / The Kerner Equation / The Guth-Smallwood Equation / The Davies Equation / Example Calculations with the Davies Equation / The Morphology of Multiphase Polymerie Materials / Phase Inversion / Example Calculation of Phase Inversion / Morphology of ABS Plastics / Phase Domain Size in Sequential IPNs / Phase Diagrams in Polymer Blends (Broad Definition) / The Order-Disorder Transition in Block Copolymers / Self-assembly in ABC Block Copolymers / Domain Periods / 599

18 CONTENTS XXIII Crystallizable Block Copolymer Morphologies / The Development of IPN Morphologies / The TTT Cure Diagram / The Metastable Phase Diagram / Morphology of Composite Materials / Reinforcing Carbon Blacks / Fiber-Reinforced Plastics / Fracture Behavior of Multiphase Polymerie Materials / Rubber-Toughened Plastics / Toughening Mechanisms in Composite Materials / Matrix and Fiber Roles in Composites / Processing and Applications of Polymer Blends and Composites / Processing of Sheet Molding Compounds / General Considerations in Application Science / Applications of Polymers, Polymer Blends, and Composites / 613 References / 617 General Reading / 619 Study Problems / Modern Polymer Topics Polyolefins / The Global Picture / Polyethylene Properties / Polypropylene Properties / Polyolefm Elastomers / Thermoset Polymer Materials / Phenol-Formaldehyde Resins / Epoxy Resins / Mechanical Behavior / Polymer and Polymer Blend Aspects of Bread Doughs / Polymer Blend Aspects of Bread Making / Morphology Changes during Baking / Mechanical Treatment (Kneading) / Bread Staling / Bread and Meatlike Textures / Silk Fiber Spinning / Dendritic Polymers and Other Novel Polymerie Structures / Aspects of Self-Assembly / 635

19 XXiV CONTENTS Polyrotaxanes / Mushroom Nanostructures / Dendrimers and Hyperbranched Polymers / Intrinsic Viscosity of Dendrimers / Electron Microscopy Studies of Dendrimers / Applications of Dendrimers / Polymers in Supercritical Fluids / General Properties of Supercritical Fluids / Dispersion Polymerization via Supercritical Fluids / Applications of Polymers in Supercritical Fluids / Electrical Behavior of Polymers / Basic Electrical Relationships / Range of Polymer Electrical Behavior / Conducting Polymers / Polymers for Nonlinear Optics / Theoretical Relationships / Experimental NLO Studies / Modern Engineering Plastics / Major Advances in Polymer Science and Engineering / 650 Index References / 652 General Reading / 654 Study Problems / 655