Progress in Adhesion and Adhesives, Volume 4

A solid collection of interdisciplinary review articles on the latest developments in adhesion science and adhesives technology With the ever-increasing amount of research being published, it is a Herculean task to be fully conversant with the latest research developments in any field, and the arena of adhesion and adhesives is no exception. Thus, topical review articles provide an alternate and very efficient way to stay abreast of the state-of-the-art in many subjects representing the field of adhesion science and adhesives. Based on the success of the preceding volumes in this series "Progress in Adhesion and Adhesives"), the present volume comprises 9 review articles published in Volume 6 (2018) of Reviews of Adhesion and Adhesives. The subject of these reviews fall into the following general areas: 1. Adhesion to wood and wood bonds 2. Adhesive joints 3. Adhesion in microelectronic packaging 4. Surface modification 5. Contact angle, wettability and surface free energy. The topics covered include: Adhesion phenomena in microelectronic packaging; adhesives for wood and lignocellulosic materials; adhesion to wood and lignocellulosic materials; adhesively bonded lap joints having bi-adhesive and modulus-graded bondlines; adhesion between compounded elastomers; applications of contact angle measurements in pharmaceuticals and foods; oxygen or ammonia plasma treatment of polyolefin surfaces; surface free energy determination of powders and particles; wood bonds; and dispersion adhesion forces between macroscopic objects.

Table of Contents:
Preface xiii 1 Adhesion Phenomena Pertaining to Thermal Interface Materials and Solder Interconnects in Microelectronic Packaging: A Critical Review 1 Dinesh P R Thanu, Aravindha Antoniswamy, Roozbeh Danaei and Manish Keswani 1.1 Introduction 2 1.2 Polymer Thermal Interface Material -Metal Interface Adhesion Phenomena 3 1.2.1 Basics of Thermal Interface Material Adhesion 3 1.2.2 Current Status of Thermal Interface Materials and their Bonding Mechanisms 5 1.2.3 Chemical Bonding 6 1.2.4 Mechanical Interlocking 12 1.2.5 Weak Boundary Layer 14 1.3 Ball Grid Array Solder Attach Adhesion Phenomena 14 1.3.1 Solder Alloy Selection 15 1.3.2 Flux Selection 18 1.4 Summary 19 Nomenclature 20 References 21 2 Influence of Silicon-Containing Compounds on Adhesives for and Adhesion to Wood and Lignocellulosic Materials: A Critical Review 25 Marko Petricˇ 2.1 Introduction 26 2.2 An Overview of Compounds and Natural Minerals Containing the Element Si, which are the Most Relevant in the Science and Technology of Lignocellulosics 29 2.2.1 Silica – SiO2 29 2.2.2 Silicates and Clay 30 2.2.3 Silicones 32 2.2.4 Silanes and Silsesquioxanes 33 2.3 Si-containing Compounds in Adhesives and in Lignocellulosic Substrates and their Influence on the Performance of Adhesive Bonds 35 2.3.1 Compounds of Silicon in Adhesives 35 2.3.1.1 Inorganic Compounds of Si (Silica, Silicates, Clay, and Other Inorganic Compounds) 35 2.3.1.2 Organosilicon Compounds in Adhesives 40 2.3.2 Silicon-containing Compounds in Lignocellulosics with Regard to the Properties of Adhesive Bonds 42 2.3.3 Influence of Si in Coatings or in Lignocellulosic Substrates with Regard to Coatings Adhesion to the Substrates 44 2.4 Interactions of the Si Compounds with Lignocellulosics 46 2.4.1 Interactions with Silica 46 2.4.2 Interactions with Silicates 48 2.4.3 Interactions with Silicones 49 2.4.4 Interactions with Organosilicon Compounds and Coupling Agents 50 2.4.4.1 Interactions with Organosilicon Compounds 50 2.4.4.2 Coupling Agents 52 2.5 Wood- and Lignocellulose-based Composites Containing Si Compounds 57 2.5.1 Composites Containing Silica 57 2.5.2 Composites Containing Silicates and Clay 59 2.5.3 Composites Containing Silicones 60 2.5.4 Composites with Organosilicon Compounds 61 2.6 Summary and General Remarks 64 2.7 Acknowledgments 65 References 65 3 Recent Advances in Adhesively Bonded Lap Joints Having Bi-Adhesive and Modulus-Graded Bondlines: A Critical Review 77 Özkan Öz and Halil Özer 3.1 Introduction 77 3.2 Bi-adhesive Joints 80 3.2.1 Numerical and Analytical Studies 80 3.2.2 Experimental Studies 84 3.3 Modulus-Graded Bondline 88 3.3.1 Numerical and Analytical Studies 88 3.3.2 Experimental Studies 91 3.4 Summary 94 Acknowledgement 94 Nomenclature 94 References 94 4 Adhesion between Compounded Elastomers: A Critical Review 99 K. Dinesh Kumar, M.S. Satyanarayana, Ganesh C. Basak and Anil K. Bhowmick 4.1 Introduction 100 4.2 Co-crosslinking 101 4.2.1 Adhesion Between Unvulcanized Rubber (Filled with Crosslinking Agents) and Unvulcanized Rubber (Filled with Crosslinking Agents) by Co-crosslinking 104 4.2.2 Adhesion Between Partially Vulcanized Rubber (Filled with Crosslinking Agents) and Partially Vulcanized Rubber (Filled with Crosslinking Agents) by Co-crosslinking 118 4.3 Adhesion Between Vulcanized Rubber and Unvulcanized Rubber or Partially Vulcanized Rubber 138 4.3.1 Adhesion between Vulcanized Rubber and Unvulcanized Rubber (Filled with Crosslinking Agents) 140 4.3.2 Adhesion between Vulcanized Rubber and Partially Vulcanized Rubber (Filled with Crosslinking Agents) 164 4.4 Adhesion Between Vulcanized Rubber and Vulcanized Rubber 166 4.5 Summary 184 Acknowledgements 186 List of Symbols 186 List of Abbreviations 187 References 189 5 Contact Angle Measurements and Applications in Pharmaceuticals and Foods: A Critical Review 193 Davide Rossi, Paola Pittia and Nicola Realdon 5.1 Introduction 194 5.1.1 Prospects 199 5.2 Contact Angle Measurements in Pharmaceutical Field 200 5.2.1 Pharmaceutical Powders 200 5.2.2 Solvents for Pharmaceutical Use 211 5.2.3 Injectable Solutions for Parenteral Use 218 5.3 Contact Angle Measurements in Foods 222 5.3.1 Solid Foods 222 5.3.2 Liquid Foods and Beverages 231 5.3.3 Food Packaging 234 5.4 Summary 236 Acknowledgement 236 References 237 6 The Formation Processes of Functional Groups at Polyolefin Surfaces on Exposure to Oxygen or Ammonia Plasma: A Critical Review 241 Jörg Friedrich 6.1 Introduction 242 6.1.1 Reasons for Polyolefin Surface Functionalization 242 6.1.2 Energetic Considerations, Thermodynamics and Probability of Reactions 245 6.1.3 Processes on Molecular Level at Polyolefin Surface 249 6.2 Oxygen Plasma Treatment 254 6.2.1 Formation of O Functional Groups at Polyolefin Surfaces on Exposure to Oxygen Plasma 254 6.2.2 Kinetics of Polyolefin Oxidation – Dependence on Parameters 260 6.2.3 Influence of Type of Plasma Gas 262 6.2.4 Influence of Polymer Composition 263 6.2.5 Auto-Oxidation 265 6.2.6 Oxidation by Exposure to Noble Gas Plasmas 267 6.2.7 Generation of OH Groups on the Surface of Polyolefins by Deposition of a Thin Layer of Poly(allyl alcohol) Plasma Polymer 269 6.3 Ammonia Plasma for Introduction of NH2 Groups onto Polyolefin Surfaces 272 6.3.1 Production of Primary Amino Groups on Exposure to Plasma 274 6.3.2 Thermodynamic Aspects 275 6.3.3 Ammonia Plasma 277 6.3.4 Formation of Functional Groups on Exposure to NH3 Plasma 278 6.3.5 Kinetics of N and NH2 Introduction on Exposure to Ammonia or Nitrogen-Hydrogen Plasmas 280 6.3.6 Side-Reactions at Polyolefin Surfaces on Exposure to NH3 Plasma 283 6.3.6.1 Hydrogenation and Dehydrogenation 284 6.3.6.2 Post-Plasma Oxidation 286 6.3.6.3 Nitrile Formation 286 6.3.7 NH2 Groups via Plasma Polymerization of Allylamine and Other N-Precursors 290 6.3.8 Attempts to Increase the Concentration of NH2 Groups by Addition of Ammonia to Allylamine Plasma Polymerization 294 6.3.9 Significant Side-Reactions During and After Plasma Polymerization of Allylamine 294 6.4 Discussion 297 6.5 Summary 303 Acknowledgement 304 References 304 7 Surface Free Energy Determination of Powders and Particles with Pharmaceutical Applications: A Critical Review 315 Frank M. Etzler and Douglas Gardner 7.1 Introduction 315 7.2 Surface Thermodynamic Quantities of Pure Materials 316 7.3 Contact Angle Methods 320 7.3.1 The Zisman Method 320 7.3.2 The van Oss, Chaudhury and Good Method 320 7.3.2.1 Methods for Calculating the van Oss, Chaudhury and Good Parameters 324 7.3.3 The Chang – Chen Method 325 7.4 Determination of Surface Free Energy using IGC and AFM 326 7.4.1 Application of the Fowkes Method to IGC Data 326 7.4.2 Application of the van Oss, Chaudhury and Good Method to IGC Data 328 7.4.3 Application of the Chang-Chen Model to IGC Data 329 7.4.4 AFM Methods 329 7.5 Characterizing Surface Properties by Inverse Gas Chromatography 331 7.5.1 IGC Measurements - Experimental Considerations 332 7.5.2 Finite Dilution IGC 339 7.6 Pharmaceutical Applications 340 7.6.1 Surface Free Energy and Crystal Planes 340 7.6.2 Compaction of Tablets 341 7.6.3 Effects of Processing on Surface Free Energy 342 7.6.4 Performance of Dry Powder Inhalers 344 7.6.5 Powder Flow 345 7.7 Summary 346 References 347 8 Understanding Wood Bonds–Going Beyond What Meets the Eye: A Critical Review 353 Christopher G. Hunt, Charles R. Frihart, Manfred Dunky and Anti Rohumaa 8.1 Introduction: Macroscopic Knowledge for Successful Adhesive Bonding of Wood 353 8.2 Bond Formation (Developing Adhesion) 356 8.2.1 Influence of Wood Structure on Bonding 356 8.2.2 Influence of Wood Surface Quality on Bonding 360 8.2.2.1 Mechanical Damage at the Wood Surface 361 8.2.2.2 Surface Chemistry Barriers to Bonding 365 8.2.3 Adhesive Penetration 367 8.2.3.1 Void Penetration (Bulk Flow) 368 8.2.3.2 Cell Wall Penetration (Infiltration) 370 8.2.4 Adhesive Properties that Influence Void and Cell Wall Penetration 373 8.3 Properties of Adhesive-Wood Assemblies 375 8.3.1 Zones in a Wood Bond 375 8.3.2 How Adhesives Accommodate Wood Swelling 376 8.3.3 Two Classes of Adhesives 377 8.3.4 Methods for Determining Void and Cell Wall Penetration 379 8.2.4.1 Quantifying Depth of Void Penetration 386 8.3.5 Shortcomings of Standardized Tests 387 8.4 A More Detailed Approach than Standard Wood Failure Analysis 388 8.4.1 Going Beyond What Meets the Eye to Understand Epoxy Failure 389 8.4.2 Using SEM to Detect Brittle Failure in UF 391 8.4.3 Alternative Mechanical Methods of Testing for More Information 391 8.5 Unresolved Questions in Wood Bonding Research 393 8.5.1 How Do We Make Wood Surfaces Better for Bonding? 393 8.5.2 Does the Adhesive Have Good Penetration into the Wood Structure? 394 8.5.3 How Does the Adhesive Interact with the Wood at the Nanoscale and Molecular Level? 394 8.5.4 Can We Improve the Resistance of Bonds to the Dimensional Changes in Wood with Variation in Moisture? 395 8.5.5 How do Primers Work? 395 8.5.6 Where Does the Bond Failure Initiate and How Does it Propagate? 396 8.5.7 How Do We Optimize the Benefits of Cell Wall Penetration? 396 8.5.8 How Does the Adhesive Form a Suitable Polymer Matrix to Bridge Between the Two Wood Surfaces? 397 8.5.9 Will Adhesives Based on Renewable Resources be the Future in Wood Bonding? 397 8.5.10 How Much the Experience with Solid Wood Bonding can be Used to Understand Wood Based Particulate Bonding? 398 8.5.11 How Do We Compare Results Obtained in Different Laboratories with Different Wood Species with Different Adhesives? 398 8.6 Summary 399 List of Abbreviations 399 References 400 9 Dispersion Adhesion Forces between Macroscopic Objects–Basic Concepts and Modelling Techniques: A Critical Review 421 Youcef Djafri and Djamel Turki 9.1 Introduction 421 9.2 Basic Concepts 422 9.3 Modeling Techniques 424 9.3.1 The Microscopic Theory (Hamaker’s Approach) 424 9.3.2 The Proximity-Force Approximation 426 9.3.3 The Retardation Effect 427 9.3.3.1 The Retarded vdW Forces 427 9.3.3.2 Retardation in Macroscopic Bodies 428 9.3.4 The Casimir Effect 429 9.3.5 Worldline Calculations of the Casimir Effect 431 9.3.6 The Macroscopic Theory of Van der Waals Forces (DLP Method) 431 9.3.7 The Coupled Dipole Method 434 9.4 Discussion and Prospects 437 9.5 Summary 438 References 439

About the Author :
Kashmiri Lal Mittal was employed by the IBM Corporation from 1972 through 1993. Currently, he is teaching and consulting worldwide in the broad areas of adhesion as well as surface cleaning. He has received numerous awards and honors including the title of doctor honoris causa from Maria Curie-Sk??odowska University, Lublin, Poland. He is the editor of more than 130 books dealing with adhesion measurement, adhesion of polymeric coatings, polymer surfaces, adhesive joints, adhesion promoters, thin films, polyimides, surface modification surface cleaning, and surfactants. Dr. Mittal is also the Founding Editor of the journal Reviews of Adhesion and Adhesives.