Rubber-Clay Nanocomposites

The one–stop resource for rubber–clay nanocomposite information The first comprehensive, single–volume book to compile all the most important data on rubber–clay nanocomposites in one place, Rubber–Clay Nanocomposites: Science, Technology, and Applications reviews rubber–clay nanocomposites in an easy–to–reference format designed for R&D professionals. Including contributions from experts from North America, Europe, and Asia, the book explores the properties of compounds with rubber–clay nanocomposites, including their rheology, curing kinetics, mechanical properties, and many others. Rubber–clay nanocomposites are of growing interest to the scientific and technological community, and have been shown to improve rubber compound reinforcement and impermeability. These natural mineral fillers are of potential interest for large–scale applications and are already making an impact in several major fields. Packed with valuable information about the synthesis, processing, and mechanics of these reinforced rubbers, the book covers assorted rubber–clay nanocomposites applications, such as in automotive tires and as polymer fillers. Promoting common knowledge and interpretation of the most important aspects of rubber–clay nanocomposites, and clarifying the main results achieved in the field of rubbers and crosslinked rubbers—something not covered in other books in the field— Rubber–Clay Nanocomposites helps scientists understand morphology, vulcanization, permeability, processing methods, and characterization factors quickly and easily.

PREFACE xvii CONTRIBUTORS xxi SECTION I CLAYS FOR NANOCOMPOSITES 1 CLAYS AND CLAY MINERALS 3 1.1 What’s in a Name / 3 1.2 Multiscale Organization of Clay Minerals / 6 1.2.1 Dispersion Versus Aggregation / 6 1.2.2 Delamination/Exfoliation Versus Stacking / 6 1.3 Intimate Organization of the Layer / 8 1.3.1 Cationic and Neutral Clay Minerals / 8 1.3.2 Anionic Clay Minerals (O) / 21 1.4 Most Relevant Physicochemical Properties of Clay Mineral / 22 1.4.1 Surface Area and Porosity / 22 1.4.2 Chemical Landscape of the Clay Surfaces / 24 1.4.3 Cation (and Anion) Exchange Capacity / 24 1.4.4 Intercalation and Confinement in the Interlayer Space / 27 1.4.5 Swelling / 30 1.4.6 Rheology / 31 1.5 Availability of Natural Clays and Synthetic Clay Minerals / 33 1.6 Clays and (Modified) Clay Minerals as Fillers / 35 Acknowledgment / 37 References / 37 2 ORGANOPHILIC CLAY MINERALS 45 2.1 Organophilicity/Lipophilicity and the Hydrophilic/Lipophilic Balance (HLB) / 45 2.2 From Clays to Organoclays in Polymer Technology / 47 2.3 Methods of Organoclay Synthesis / 49 2.3.1 Cation Exchange from Solutions / 49 2.3.2 Solid–State Intercalation / 58 2.3.3 Grafting from Solution / 59 2.3.4 Direct Synthesis of Grafted Organoclays / 62 2.3.5 Postsynthesis Modifications of Organoclays: The “PCH” / 64 2.3.6 An Overview of Commercial Organoclays / 64 2.3.7 One–Pot CPN Formation / 66 2.4 Other Types of Clay Modifications for Clay–Based Nanomaterials / 66 2.4.1 Organo–Pillared Clays / 66 2.4.2 Plasma–Treated Clays / 69 2.5 Fine–Tuning of Organoclays Properties / 69 2.5.1 Maximizing the Dispersion of the Filler: Effect of Surfactant/CEC Ratio / 69 2.5.2 Improving Thermal Stability / 70 2.5.3 Chemical Treatments / 71 2.5.4 Physical Treatments (Freeze–Drying, Sonication, Microwave) / 71 2.6 Some Introductory Reflections on Organoclay Polymer Nanocomposites / 72 References / 75 3 INDUSTRIAL TREATMENTS AND MODIFICATION OF CLAY MINERALS 87 3.1 Bentonite: From Mine to Plant / 87 3.1.1 A Largely Diffused Clay / 87 3.1.2 Geological Occurrence / 89 3.1.3 Mining / 89 3.2 Processing of Bentonite / 90 3.2.1 Modification of Bentonite Properties / 90 3.2.2 Processing Technologies / 91 3.3 Purification of Clay / 93 3.3.1 Influence of Clay Concentration / 94 3.3.2 Influence of Swelling Time / 94 3.3.3 Influence of Temperature / 95 3.4 Reaction of Clay with Organic Substances / 97 3.5 Particle Size Modification / 99 References / 99 4 ALKYLAMMONIUM CHAINS ON LAYERED CLAY MINERAL SURFACES 101 4.1 Structure and Dynamics / 101 4.1.1 Packing Density and Self–Assembly / 102 4.1.2 Dynamics and Diffusion at the Clay–Surfactant Interface / 110 4.1.3 Utility of Molecular Simulation to Obtain Molecular–Level Insight / 111 4.2 Thermal Properties / 111 4.2.1 Reversible Melting Transitions of Alkyl Chains in the Interlayer / 111 4.2.2 Solvent Evaporation and Thermal Elimination of Alkyl Surfactants / 113 4.3 Layer Separation and Miscibility with Polymers / 115 4.3.1 Thermodynamics Model for Exfoliation in Polymer Matrices / 115 4.3.2 Cleavage Energy / 116 4.3.3 Surface Energy / 121 4.4 Mechanical Properties of Clay Minerals / 121 References / 123 5 CHEMISTRY OF RUBBER–ORGANOCLAY NANOCOMPOSITES 127 5.1 Introduction / 127 5.2 Organic Cation Decomposition in Salts, Organoclays and Polymer Nanocomposites / 128 5.2.1 Experimental Techniques / 128 5.2.2 Decomposition of Organoclays Versus Precursor Organic Cation Salts / 133 5.3 Mechanism of Thermal Decomposition of Organoclays / 135 5.4 Role of Organic Cations in Organoclays as Rubber Vulcanization Activators / 137 References / 141 SECTION II PREPARATION AND CHARACTERIZATION OF RUBBER–CLAY NANOCOMPOSITES 6 PROCESSING METHODS FOR THE PREPARATION OF RUBBER–CLAY NANOCOMPOSITES 147 6.1 Introduction / 147 6.2 Latex Compounding Method / 148 6.2.1 Mechanism / 148 6.2.2 Influencing Factors / 149 6.3 Melt Compounding / 157 6.3.1 Mechanism / 157 6.3.2 Influencing Factors / 160 6.4 Solution Intercalation and In Situ Polymerization Intercalation / 170 6.5 Summary and Prospect / 170 Acknowledgment / 171 References / 171 7 MORPHOLOGY OF RUBBER–CLAY NANOCOMPOSITES 181 7.1 Introduction / 181 7.1.1 Focus, Objective and Structure of Chapter 7 / 181 7.1.2 X–Ray Diffraction Analysis for the Investigation of RCN / 182 7.2 Background for the Review of RCN Morphology / 182 7.2.1 Cationic Clays Used for the Preparation of Rubber Nanocomposites / 182 7.2.2 Multiscale Organization of Layered Clays / 184 7.2.3 Clay Distribution and Dispersion / 184 7.2.4 Clay Modification: Intercalation of Low Molecular Mass Substances / 184 7.2.5 Types of Polymer–Clay Composites / 184 7.2.6 Specific Literature on RCN / 186 7.3 Rubber–Clay Nanocomposites with Pristine Clays / 186 7.3.1 Rubber Nanocomposites with Cationic Clays / 187 7.3.2 In a Nutshell / 187 7.3.3 Distribution and Dispersion of a Pristine Clay in a Rubber Matrix / 190 7.3.4 Organization of Aggregated Pristine Clays / 194 7.4 Rubber–Clay Nanocomposites with Clays Modified with Primary Alkenylamines / 197 7.4.1 In a Nutshell / 197 7.4.2 Composites with Montmorillonite and Bentonite / 198 7.4.3 Composites with Fluorohectorite Modified with a Primary Alkenylamine / 202 7.5 Rubber–Clay Nanocomposites with Clays Modified with an Ammonium Cation Having three Methyls and One Long–Chain Alkenyl Substituents / 206 7.5.1 In a Nutshell / 206 7.5.2 Composites with Montmorillonite and Bentonite / 207 7.6 Rubber–Clay Nanocomposites with Montmorillonite Modified with Two Substituents Larger Than Methyl / 212 7.6.1 In a Nutshell / 212 7.6.2 Hydrogenated Tallow and Benzyl Groups as Ammonium Cation Substituents / 213 7.6.3 Hydrogenated Tallow and Ethylhexyl Groups as Ammonium Cation Substituents / 213 7.6.4 Other Long– and Short–Chain Alkenyl Groups as Ammonium Cation Substituents / 215 7.7 Rubber Composites with Montmorillonite Modified with an Ammonium Cation Containing a Polar Group / 215 7.7.1 In a Nutshell / 217 7.7.2 Composites with Diene Rubbers / 217 7.8 Rubber Nanocomposites with Montmorillonite Modified with an Ammonium Cation Containing Two Long–Chain Alkenyl Substituents / 219 7.8.1 In a Nutshell / 220 7.8.2 Composites with Two Talloyl Groups as Ammonium Cation Substituents / 220 7.9 Proposed Mechanisms for the Formation of Rubber–Clay Nanocomposites / 228 7.9.1 Two Mechanisms for the Formation of an Exfoliated Clay / 228 7.9.2 Two Mechanisms for the Formation of an Intercalated Organoclay / 228 7.9.3 Intercalation of Polymer Chains in the Interlayer Space / 229 7.9.4 Intercalation of Low Molecular Mass Substances in the Interlayer Space / 230 Abbreviations / 232 Acknowledgment / 233 References / 233 8 RHEOLOGY OF RUBBER–CLAY NANOCOMPOSITES 241 8.1 Introduction / 241 8.2 Rheological Behavior of Rubber–Clay Nanocomposites / 242 8.2.1 Natural Rubber (NR), Epoxidized Natural Rubber (ENR) and Polyisoprene Rubber (IR)–Clay Nanocomposites / 243 8.2.2 Styrene–Butadiene Rubber (SBR)–Clay Nanocomposites / 246 8.2.3 Polybutadiene Rubber (BR)–Clay Nanocomposites / 247 8.2.4 Acrylonitrile Butadiene Rubber (NBR)–Clay Nanocomposites / 250 8.2.5 Ethylene Propylene Rubber–Clay Nanocomposites / 253 8.2.6 Fluoroelastomer–Clay Nanocomposites / 254 8.2.7 Poly(isobutylene–co–para–methylstyrene) (BIMS) Rubber–Clay Nanocomposites / 257 8.2.8 Poly(ethylene–co–vinylacetate) (EVA) Rubber–Clay Nanocomposites / 257 8.2.9 Polyepichlorohydrin Rubber–Clay Nanocomposites / 259 8.2.10 Thermoplastic Polyurethane (TPU)–Clay Nanocomposites / 261 8.2.11 Styrene–Ethylene–Butylene–Styrene (SEBS) Block Copolymer–Clay Nanocomposites / 262 8.3 General Remarks on Rheology of Rubber–Clay Nanocomposites / 263 8.4 Overview of Rheological Theories of Polymer–Clay Nanocomposites / 269 8.5 Conclusion and Outlook / 270 References / 271 9 VULCANIZATION CHARACTERISTICS AND CURING KINETIC OF RUBBER–ORGANOCLAY NANOCOMPOSITES 275 9.1 Introduction / 275 9.2 Vulcanization Reaction / 276 9.3 Rubber Cross–Linking Systems / 278 9.3.1 Sulfur Vulcanization / 278 9.3.2 Peroxide Vulcanization / 282 9.4 The Role of Organoclay on Vulcanization Reaction / 283 9.4.1 Influence of Organoclay Structural Characteristics on Rubber Vulcanization / 288 9.5 Vulcanization Kinetics of Rubber–Organoclay Nanocomposites / 290 9.6 Conclusions / 297 References / 298 10 MECHANICAL AND FRACTURE MECHANICS PROPERTIES OF RUBBER COMPOSITIONS WITH REINFORCING COMPONENTS 305 10.1 Introduction / 305 10.2 Testing of Viscoelastic and Mechanical Properties of Reinforced Elastomeric Materials / 307 10.2.1 Dynamic–Mechanical Analysis / 307 10.2.2 Tensile Testing / 310 10.2.3 Assessment of Toughness Behavior under Impact–Like Loading Conditions / 313 10.2.4 Hardness Testing / 315 10.2.5 Special Methods / 316 10.3 Characterization of the Fracture Behavior of Elastomers / 319 10.3.1 Fracture Mechanics Concepts / 319 10.3.2 Experimental Methods / 321 10.4 Mechanism of Reinforcement in Rubber–Clay Composites / 328 10.5 Theories and Modeling of Reinforcement / 333 Acknowledgment / 336 References / 336 11 PERMEABILITY OF RUBBER COMPOSITIONS CONTAINING CLAY 343 11.1 Introduction / 343 11.1.1 Butyl Rubbers as Nanocomposite Base Elastomers / 343 11.1.2 Measurement of Tire Innerliner Compound Permeability / 345 11.1.3 Further Improvement in Tire Permeability / 346 11.2 Nanocomposites / 346 11.3 Preparation of Elastomer Nanocomposites / 352 11.4 Temperature and Compound Permeability / 352 11.5 Vulcanization of Nanocomposite Compounds and Permeability / 356 11.6 Thermodynamics and BIMSM Montmorillonite Nanocomposites / 358 11.7 Nanocomposites and Tire Performance / 362 11.8 Summary / 364 References / 364 SECTION III COMPOUNDS WITH RUBBER–CLAY NANOCOMPOSITES 12 RUBBER–CLAY NANOCOMPOSITES BASED ON APOLAR DIENE RUBBER 369 12.1 Introduction / 369 12.2 Preparation Methods / 371 12.2.1 Latex / 371 12.2.2 Solution / 373 12.2.3 Melt Blending / 374 12.3 Cure Characteristics / 377 12.4 Clay Dispersion / 379 12.4.1 Detection / 380 12.4.2 Characterization / 383 12.5 Properties / 387 12.5.1 Mechanical (Dynamic–Mechanical) / 387 12.5.2 Friction/Wear/Abrasion / 392 12.5.3 Barrier / 393 12.5.4 Fire Resistance / 396 12.5.5 Others / 397 12.6 Applications and Future Trends / 398 Acknowledgment / 399 References / 399 13 RUBBER–CLAY NANOCOMPOSITES BASED ON NITRILE RUBBER 409 13.1 Introduction / 409 13.2 Preparation Methods and Clay Dispersion / 410 13.2.1 Solution / 410 13.2.2 Latex / 411 13.2.3 Melt Blending / 412 13.3 Cure Characteristics / 414 13.4 Properties / 416 13.4.1 Mechanical (Dynamic–Mechanical) / 416 13.4.2 Friction/Wear / 421 13.4.3 Barrier / 423 13.4.4 Fire Resistance / 424 13.4.5 Others / 425 13.5 Outlook / 425 Acknowledgment / 426 References / 426 xii CONTENTS FOR SCREEN VIEWING IN DART ONLY 14 RUBBER–CLAY NANOCOMPOSITES BASED ON BUTYL AND HALOBUTYL RUBBERS 431 14.1 Introduction / 431 14.1.1 Butyl Rubber: Key Properties and Applications / 431 14.1.2 Butyl Rubber–Clay Nanocomposites / 433 14.2 Types of Clays Useful in Butyl Rubber–Clay Nanocomposites / 435 14.2.1 Montmorillonite Clays / 435 14.2.2 Hydrotalcite Clays / 435 14.2.3 High Aspect Ratio Talc Fillers / 436 14.2.4 Other Clays / 437 14.3 Compatibilizer Systems for Butyl Rubber–Clay Nanocomposites / 438 14.3.1 Surfactants and Swelling Agents / 439 14.3.2 Butyl Rubber Ionomers / 439 14.3.3 Maleic Anhydride–Grafted Polymers / 443 14.3.4 Low Molecular Weight Polymers and Resins / 444 14.4 Methods of Preparation of Butyl Rubber–Clay Nanocomposites / 444 14.4.1 Melt Method / 445 14.4.2 Solution Method / 445 14.4.3 Latex Method / 447 14.4.4 In Situ Polymerization / 448 14.5 Properties and Applications of Butyl Rubber–Clay Nanocomposites / 449 14.5.1 Air Barrier Properties / 449 14.5.2 Reinforcement Properties / 452 14.5.3 Vulcanization Properties / 454 14.5.4 Adhesion Properties / 456 14.5.5 Other Properties / 457 14.6 Conclusions / 457 References / 458 15 RUBBER–CLAY NANOCOMPOSITES BASED ON OLEFINIC RUBBERS (EPM, EPDM) 465 15.1 Introduction / 465 15.2 Types of Clay Minerals Useful in EPM–, EPDM–Clay Nanocomposites / 466 15.3 Compatibilizer Systems for Olefinic Rubber–Clay Nanocomposites / 467 15.4 Preparation of EPDM–Clay Nanocomposites by an In Situ Intercalation Method / 469 15.5 Characteristics of EPDM–Clay Nanocomposites / 473 15.5.1 Gas Barrier Properties of EPDM–Clay Nanocomposites / 473 15.5.2 Rheological Properties of EPDM–Clay Nanocomposites / 474 15.5.3 Stability of EPDM–Clay Nanocomposites / 475 15.5.4 Swelling Properties of EPDM–Clay Nanocomposites / 475 15.5.5 Mechanical Properties of EPDM–Clay Nanocomposites / 476 15.6 Preparation and Characteristics of EPM–Clay Nanocomposites / 479 15.6.1 Tensile Properties of EPM–CNs / 480 15.6.2 Temperature Dependence of Dynamic Storage Moduli of EPM–CNs / 481 15.6.3 Creep Properties of EPM–CNs / 482 15.6.4 Swelling Properties of EPM–CNs / 483 15.7 Conclusions / 486 References / 486 16 RUBBER–CLAY NANOCOMPOSITES BASED ON THERMOPLASTIC ELASTOMERS 489 16.1 Introduction / 489 16.2 Selection of Materials / 491 16.2.1 Polymer Resin / 491 16.2.2 Nanoparticles / 493 16.3 Experimental / 493 16.3.1 Processing of Thermoplastic Elastomer Nanocomposites / 493 16.3.2 Morphological Characterization / 494 16.3.3 Thermal Properties Characterization / 495 16.3.4 Flammability Properties Characterization / 495 16.3.5 Thermophysical Properties Characterization / 496 16.4 Numerical / 497 16.4.1 Modeling of Decomposition Kinetics / 497 16.5 Discussion of Results / 501 16.5.1 Nanoparticle Dispersion / 501 16.5.2 Thermal Properties / 503 16.5.3 Flammability Properties / 507 16.5.4 Microstructures of Posttest Specimens / 511 16.5.5 Thermophysical Properties / 512 16.5.6 Kinetic Parameters / 513 16.6 Summary and Conclusions / 516 16.7 Nomenclature / 517 Acknowledgments / 518 References / 518 SECTION IV APPLICATIONS OF RUBBER–CLAY NANOCOMPOSITES 17 AUTOMOTIVE APPLICATIONS OF RUBBER–CLAY NANOCOMPOSITES 525 17.1 Introduction / 525 17.2 Automotive Application of Rubber / 526 17.2.1 Automotive Hose / 527 17.2.2 Automotive Seals / 528 17.2.3 Automotive Belts / 529 17.2.4 Automotive Tubing / 529 17.2.5 Door Seal and Window Channels / 529 17.2.6 Diaphragms and Rubber Boots / 529 17.2.7 Tire, Tube and Flap / 529 17.2.8 Other Miscellaneous Rubber Parts / 531 17.3 Prime Requirement of Different Elastomeric Auto Components from Application Point of View / 531 17.4 Elastomeric Nanocomposites and Rubber Industry / 531 17.5 Superiority of Clay/Clay Mineral in Comparison to Other Nanofillers / 534 17.6 Organo–Modified Clay/Clay Minerals / 534 17.7 Scope of Application of Elastomeric Nanocomposites in Automotive Industry / 534 17.7.1 Lighter Weight and Balanced Mechanical Property / 535 17.7.2 Barrier Property or Air Retention Property / 538 17.7.3 Aging and Ozone Resistance / 539 17.7.4 Solvent Resistance / 541 17.7.5 Better Processability / 542 17.7.6 Elastomeric Polyurethane–Organoclay Nanocomposites / 544 17.7.7 Use of Organoclay Nanocomposites in Tire / 545 17.8 Disadvantages of Use of Organoclay Elastomeric Nanocomposites in Automotive Industry / 548 17.9 Conclusion / 549 Acknowledgment / 550 References / 550 18 NONAUTOMOTIVE APPLICATIONS OF RUBBER–CLAY NANOCOMPOSITES 557 18.1 Water–Based Nanocomposites / 557 18.1.1 Barrier Properties / 557 18.1.2 Comparison with Thermally Processed Elastomers / 566 18.2 Applications / 566 18.2.1 Sports Balls and Other Pneumatic Applications / 566 18.2.2 Breakthrough Time Applications / 571 References / 573 INDEX 575