Biobased Adhesives

Preface xvii

Part 1: Fundamental Aspects 1
1 Introduction to Naturally-Based (Bio-) Adhesives 3
Manfred Dunky
1.1 Introduction 3
1.2 Overview and Challenges For Adhesives Based on Natural Resources 6
1.2.1 Combined Use of Synthetic and Naturally-Based Adhesives 8
1.2.2 Overview on Adhesives Based on Natural Resources 9
1.2.3 Requirements, Limitations, and Opportunities for Wood Adhesives Based on Natural Resources 11
1.3 Biorefinery and Platform Chemicals 11
1.4 Lignin as Raw Material for Platform Chemicals 20
1.5 5-Hydroxymethylfurfural (5-HMF) as Platform Chemical 23
1.6 Mimicking Nature 27
1.7 Special Topics and Latest Developments 29
1.8 Prospects 30
1.9 Summary 30
General Literature on Biobased Adhesives 30
List of Abbreviations 34
References 35

2 Adhesion Theories in Naturally-Based Bonding: Adhesion and Surface Issues with Naturally-Based Adhesives 45
Douglas J. Gardner, Geeta Pokhrel and Alexander Collins
2.1 Introduction 45
2.2 Adhesion Theories 46
2.2.1 Mechanical Interlocking 47
2.2.2 Electrostatic Mechanism 48
2.2.3 Adsorption (Thermodynamic) or Wetting Mechanism 49
2.2.4 Diffusion Mechanism 50
2.2.5 Chemical (Covalent) Bonding Mechanism 50
2.2.5.1 Hydrogen Bonding 51
2.2.6 Acid-Base Theory 51
2.2.7 Weak Boundary Layers 52
2.2.8 Stickiness or Tackiness 53
2.3 Protein Adhesives 54
2.3.1 Animal-Sourced Proteins 55
2.3.2 Plant Proteins 57
2.4 Carbohydrate-Based Adhesives 59
2.5 Plant or Wood-Based Extractives 60
2.5.1 Rubber 60
2.5.2 Resins 61
2.5.2.1 Rosin 62
2.5.2.2 Terpene Resins 63
2.5.2.3 Tannins 64
2.5.2.4 Gums 65
2.6 Fats or Oils 66
2.6.1 Tung Oil 67
2.6.2 Linseed Oil 68
2.6.3 Soybean Oil 69
2.6.4 Castor Oil 70
2.6.5 Miscellaneous Oils 71
2.7 Summary 72
Acknowledgements 72
List of Abbreviations 72
References 74

3 The Chemistry of Bioadhesives 85
A. Pizzi
3.1 Introduction 85
3.2 Carbohydrate Bioadhesives 86
3.3 Protein Bioadhesives 91
3.4 Lignin-Based Bioadhesives 93
3.5 Tannin-Based Bioadhesives 95
3.5.1 Hydrolysable Tannins 96
3.5.1.1 Gallo-Tannins 96
3.5.1.2 Ellagi-Tannins 96
3.5.2 Condensed Polyflavonoid Tannins 96
3.5.3 Reactions of Condensed Flavonoid Tannins 99
3.6 Other Bio-Adhesives for Wood Composites 106
3.7 Summary 108
List of Abbreviations 109
References 110

4 Biorefinery Products as Naturally-Based Key Raw Materials for Adhesives 119
Johannes Karl Fink
4.1 Biorefinery Systems 119
4.1.1 History of Biomaterials 119
4.1.2 Classification of Biorefinery Systems 120
4.1.3 Biorefinery Processes 123
4.1.3.1 Hydrothermal Processes 123
4.1.3.2 Thermochemical Processes 123
4.1.3.3 Chemical Processes 124
4.1.3.4 Biochemical Processes 124
4.1.3.5 Bacterial Processes 124
4.1.4 Renewable Materials for Biorefinery 126
4.1.4.1 Carbohydrates 126
4.1.4.2 Lignin 126
4.1.4.3 Triglycerides 127
4.1.4.4 Mixed Organic Residues 127
4.2 Biobased Materials 128
4.2.1 Biobased Monomers 128
4.2.2 Synthesis Methods 129
4.2.2.1 L-3,4-Dihydroxyphenylalanine 135
4.2.2.2 2-Pyrone-4,6-dicarboxylic acid 136
4.3 Biobased Materials Suitable for Adhesives 137
4.3.1 Additives 137
4.3.2 Wood Adhesives 138
4.3.3 Lignin-Based Adhesives 139
4.3.4 Biorefinery Process of Kash 139
4.3.5 Lignin-Phenol Adhesives 140
4.3.5.1 Enzymatic Hydrolysis of Lignin 141
4.3.5.2 Biorefinery Residues 142
4.3.5.3 Phenol Replacement by Lignins 142
4.3.6 Lignin-Epoxy Adhesives 143
4.3.7 Lignosulfonates 145
4.3.8 Tannins 145
4.3.9 Protein-Based Adhesives 146
4.4 Synthesis Methods for Biobased Adhesives 147
4.4.1 Methylolated Wood-Derived Bio-Oil 147
4.4.2 Biosynthesis of Lignin 148
4.4.3 Soy-Based Adhesives 149
4.4.4 Bisphenol A-Glycidyl Methacrylate Replacement 149
4.5 Modification of Lignin for Better Performance 150
4.5.1 Functionalization with Aromatic Compounds 152
4.5.1.1 Functionalization of Lignin 153
4.5.1.2 Phenolation of Lignin 154
4.5.2 Organosolv Lignin-Based Materials 155
4.6 Pressure-Sensitive Adhesives 155
4.6.1 Lignin as Filler 156
4.6.2 Biobased Acrylic Compounds 156
4.6.3 UV-Tunable Pressure-Sensitive Adhesives 157
4.7 Summary 158
References 158

5 Natural Aldehyde-Based Thermosetting Resins 167
Manfred Dunky
5.1 Introduction 167
5.2 Aliphatic Aldehydes 168
5.2.1 Acetaldehyde 168
5.2.2 Glyoxal 169
5.2.2.1 Glyoxalation of Lignin 171
5.2.2.2 Glyoxylic Acid and Glyoxal 176
5.2.2.3 Glyoxal and Glutaraldehyde 176
5.2.2.4 Glyoxal and 5-Hydroxymethylfurfural (5-HMF) 177
5.2.3 Dimethoxy-Ethanal (Dimethoxy-Acetaldehyde, DME) 177
5.2.4 Propanal (Propionaldehyde) 178
5.2.5 Butyraldehyde 178
5.2.6 Isobutyraldehyde (Isobutanal) 179
5.2.7 Succinaldehyde (Butandial) 179
5.2.8 Glutar(di)aldehyde (GA) (Pentandial) 180
5.3 Aldehydes Based on Cyclic Structures 180
5.3.1 Furfural (Furfurylaldehyde) 180
5.3.2 Furfuryl Alcohol (FA) 184
5.3.3 5-Hydroxymethylfurfural (5-HMF) (see also Chapters 1 and 17) 185
5.3.4 2,5-Diformylfuran (2,5-Furan-Dicarbaldehyde) 192
5.3.5 Aromatic Aldehyde Precursors 193
5.3.6 Polymers with Pendent Aldehyde Groups 194
5.4 Summary 195
List of Abbreviations 195
References 198

6 Natural Crosslinkers for Naturally-Based Adhesives 207
Manfred Dunky
6.1 Introduction 207
6.2 Crosslinking Reactions 208
6.2.1 Proteins 208
6.2.2 Tannins 211
6.2.3 Carbohydrates 214
6.2.4 Lignins 217
6.3 Aliphatic Aldehydes as Crosslinkers 219
6.3.1 Formaldehyde 219
6.3.2 Higher Aldehydes 221
6.3.3 Glyoxal 221
6.3.4 Glutaraldehyde 223
6.3.5 Higher Aliphatic Aldehydes 226
6.4 Cyclic and Aromatic Aldehydes as Crosslinkers 226
6.4.1 Furfural 226
6.4.2 5-Hydroxymethylfurfural (5-HMF) 228
6.4.3 Non-Volatile Aldehydes from Carbohydrates 230
6.5 Crosslinkers Prepared from Biomass 231
6.5.1 Furfuryl Alcohol 231
6.5.2 Extracts as Crosslinkers 234
6.5.3 Glycerol Diglycidyl Ether (GDE), Glycerol Polyglycidyl Ether (GPE), and Ethylene Glycol Diglycidyl Ether (EGDE) 234
6.5.4 Triglycidylamine (TGA) 236
6.5.5 Diethylene-Triamine (DETA) 237
6.5.6 Citric Acid 237
6.6 Synthetic Crosslinkers 240
6.6.1 Polyamidoamine–Epichlorohydrin (PAE) Resins 240
6.6.2 Epoxy Resins 241
6.6.3 Polyethylenimine (PEI) 242
6.6.4 Polyamidoamine (PADA) 243
List of Abbreviations 243
References 245

7 Curing and Adhesive Bond Strength Development in Naturally-Based Adhesives 255
Milan Šernek and Jure Žigon
7.1 Introduction 255
7.2 Curing Monitoring Techniques 256
7.2.1 Gel Time Test 256
7.2.2 Differential Scanning Calorimetry (DSC) 257
7.2.3 Thermogravimetric Analysis (TGA) 258
7.2.4 Dielectric Analysis (DEA) 259
7.3 Bond Strength Development Monitoring Techniques 260
7.3.1 Dynamic Mechanical Analysis (DMA) 260
7.3.2 Thermomechanical Analysis (TMA) 261
7.3.3 Automated Bonding Evaluation System (ABES) 262
7.3.4 Tensile-Shear Strength 263
7.4 Curing Mechanisms in Naturally-Based Adhesives 263
7.4.1 Tannin-Based Adhesives 263
7.4.2 Lignin-Based Adhesives 265
7.4.3 Soy-Based Adhesives 267
7.4.4 Sucrose-Based Adhesives 269
7.4.5 Starch-Based Adhesives 270
7.4.6 Liquefied Wood (LW)-Based Adhesives 271
7.5 Summary 272
Acknowledgements 273
List of Abbreviations 273
References 274

8 Mimicking Nature: Bio-Inspired Adhesives 279
Manfred Dunky
8.1 Introduction 279
8.2 Improvement of Adhesive Performance 282
8.3 Underwater Adhesives (Wet Application Adhesives) 286
8.4 Detechable Bonding and Self-Healing Polymers 289
8.5 Medical Applications 292
8.6 Summary 294
List of Abbreviations 294
References 295

Part 2: Classes of Biobased Adhesives 305
9 Protein Adhesives – Composition, Structure and Performance 307
Charles R. Frihart
9.1 Introduction 307
9.2 Composition of Proteins 308
9.3 Types, Sources, Processing, and Properties of Proteins 309
9.3.1 Collagen (Animal) 309
9.3.2 Globular (Plant) 311
9.3.3 Globular (Milk) 315
9.3.4 Globular (Egg) 316
9.3.5 Globular (Blood) 317
9.3.6 Other Protein Sources 317
9.4 Conclusion (Future of Protein Adhesives) and Summary 317
List of Abbreviations 318
References 319

10 Carbohydrates (Polysaccharides) as Adhesives 325
Lee Seng Hua and Lum Wei Chen
10.1 Introduction 325
10.2 Cellulose Derivatives 326
10.3 Starch-Based Adhesives 330
10.4 Dextrin 331
10.5 Natural Gums 333
10.6 Chitosan 335
10.7 Summary and Prospects 339
Acknowledgements 340
List of Abbreviations 340
References 341

11 Natural Polymer-Based Adhesives 345
A.A. Shybi, Siby Varghese, Hanna J. Maria and Sabu Thomas
11.1 Introduction 345
11.2 Natural Rubber (NR)-Based Adhesives 346
11.2.1 Introduction to NR-Based Adhesives 346
11.2.2 NR-Based Wood Adhesives 350
11.2.3 NR-Based Pressure-Sensitive Adhesives 352
11.2.4 NR-Based Adhesives in Leather, Rubber, Textile and Metal Bonding Applications 353
11.3 Poly(lactic acid) (PLA)-Based Wood Adhesives 354
11.3.1 Introduction to PLA-Based Adhesives 354
11.3.2 PLA-Based Wood Adhesives 355
11.3.3 PLA-Based Hot-Melt Adhesives 356
11.3.4 PLA-Based Adhesives for Metal Bonding 357
11.4 Chitosan-Based Adhesives 357
11.4.1 Introduction to Chitosan-Based Adhesives 357
11.4.2 Chitosan-Based Wood Adhesives 358
11.5 Summary 359
List of Abbreviations 360
References 361

12 Epoxy Adhesives from Natural Materials 367
Charles R. Frihart
12.1 Introduction and Morphology 367
12.2 Basic Properties of Epoxies 369
12.3 Epoxy Synthesis 370
12.4 Epoxy Curing 373
12.4.1 One-Component Epoxies 375
12.4.2 Two-Component Epoxies 376
12.5 Aromatic Epoxies 376
12.5.1 Aromatic Bis-Phenol Epoxies 376
12.5.2 Aromatic Novolac Epoxies 377
12.5.3 Biobased Aromatic Epoxies from Polyphenols, Tannins, Cardanol, and Lignin 378
12.5.4 Aromatic Epoxies from Lignin and Woody Biomass 378
12.6 Aliphatic Epoxies 379
12.6.1 Aliphatic Epoxies from Vegetable Oils 380
12.6.2 Aliphatic Epoxies from Sugars 381
12.6.3 Aliphatic Epoxies from Terpenoids 382
12.6.4 Other Aliphatic Epoxies 382
12.7 Hardeners 383
12.7.1 Amines 383
12.7.1.1 Aliphatic Amines 383
12.7.1.2 Biobased Aliphatic Amines 384
12.7.1.3 Aromatic Amines 385
12.7.2 Anhydrides of Organic Acids 386
12.8 Other Curing Mechanisms 386
12.9 Other Additives 386
12.9.1 Tougheners 386
12.9.2 Modifiers 387
12.10 Status of Biobased Epoxy Adhesives 387
12.11 Summary 388
List of Abbreviations 389
References 389

13 Naturally-Based Polyurethane Bioadhesives 395
A. Pizzi
13.1 Introduction 395
13.2 Biopolyols-Isocyanate Polyurethanes 396
13.3 Non-Isocyanate Polyurethanes (NIPUs) 399
13.4 NIPUs as Adhesives 402
13.5 Summary 408
References 408

14 Nanocellulose-Modified Wood Adhesives 415
Stefan Veigel, Stefan Pinkl and Wolfgang Gindl-Altmutter
14.1 Introduction 415
14.2 Nanocellulose as Additive for Conventional and Biobased Wood Adhesives 416
14.3 Nanocellulose-Derived Wood Adhesives 420
14.4 Prospects 421
14.5 Summary 421
Note 422
List of Abbreviations 422
References 423

15 Debondable, Recyclable and/or Biodegradable Naturally-Based Adhesives 427
Natanel Jarach and Hanna Dodiuk
15.1 Introduction 427
15.2 Debondable Adhesives 428
15.2.1 Types of Debonding Adhesives 428
15.2.2 Reversible Covalent Bonds Containing Adhesives 429
15.3 Biobased Debondable and Recyclable Adhesives 431
15.3.1 Biodegradable Adhesives 431
15.3.2 Biobased Reversible Covalent Bonds Containing Adhesives 438
15.4 Summary 453
List of Abbreviations 453
References 454

16 Fungal Mycelia as Bioadhesives 463
Wenjing Sun, Mehdi Tajvidi and Christopher G. Hunt
16.1 Introduction 463
16.2 Basics of Fungal Mycelia 464
16.2.1 Fungal Species 464
16.2.2 Fungal Cell Wall 464
16.2.3 Effects of Fungal Mycelia on Lignocellulosic Substrates 465
16.3 Production Procedure 465
16.4 Adhesive Performance 467
16.4.1 As-Grown Foams 467
16.4.2 Hot-Pressed Panels 470
16.4.3 Engineered Living Materials 470
16.5 Improvement Strategies 470
16.5.1 Incorporating Natural Fibers 471
16.5.2 Infusing Bio-Resin 471
16.5.3 Incorporating Natural Reinforcement Particles 471
16.6 Prospects 471
16.7 Summary 471
Acknowledgements 472
List of Abbreviations 472
References 472

17 5-Hydroxymethylfurfural-Based Adhesives: Challenges and Opportunities 477
Wilfried Sailer-Kronlachner, Catherine Rosenfeld, Johannes Konnerth and Hendrikus van Herwijnen
17.1 Introduction 477
17.2 5-Hydroxymethylfurfural as Biobased Platform Chemical 479
17.2.1 Potential as Chemical Building Block 479
17.2.2 Challenges in the Implementation of an Industrial 5-HMF Production 480
17.3 5-HMF-Based Adhesive Systems 483
17.3.1 Wood Adhesives 484
17.3.2 Non-Wood Applications of 5-HMF-Based Adhesives 487
17.3.3 Examples of Adhesives Produced from 5-HMF Derivatives 488
17.4 Prospects 490
17.5 Summary 491
Acknowledgements 491
List of Abbreviations 492
References 492

18 Adhesive Precursors from Tree-Derived Naval Stores 499
Charles R. Frihart
18.1 Introduction 499
18.2 Sources and Structures 500
18.2.1 Rosins 500
18.2.2 Fatty Acids 502
18.2.3 Terpenes 503
18.3 Pressure-Sensitive Adhesives 503
18.4 Chemistry and Products 505
18.4.1 Rosins 505
18.4.2 Modification of the Carboxylic Acid 506
18.4.3 Modification of the Olefinic Portion 508
18.4.4 Ink Pigment Binders 509
18.4.5 Tall Oil Fatty Acids 510
18.4.6 Terpenes 512
18.5 Summary 513
List of Abbreviations 513
References 513

Part 3: Applications of Biobased Adhesives 517
19 Naturally-Based Adhesives for Wood and Wood-Based Panels 519
Manfred Dunky
19.1 Introduction 519
19.2 Protein-Based Wood Adhesives 521
19.2.1 Wood Bonding with Proteins 522
19.2.2 Plant-Based Proteins (for Soy Proteins see Section 19.2.3) 524
19.2.3 Soy Proteins 525
19.2.4 Animal-Based Proteins 528
19.2.5 Denaturation and Modification of Proteins 531
19.2.6 Crosslinking of Proteins 534
19.3 Wood Adhesives Based on Carbohydrates 535
19.3.1 Types and Sources of Carbohydrates for Use as Wood Adhesives 535
19.3.2 Modification of Starch for Possible Use as Wood Adhesive 537
19.3.3 Combination and Crosslinking of Carbohydrates with Natural and Synthetic Components 539
19.3.4 Degradation and Repolymerization of Carbohydrates 539
19.4 Tannin-Based Wood Adhesives 539
19.4.1 Types and Chemistry of Condensed Tannins 540
19.4.2 Hardening and Crosslinking of Tannins 542
19.4.3 Combination of Tannins with Other Components 546
19.5 Wood Adhesives Based on Lignin 547
19.5.1 Chemistry and Structure of Lignin 547
19.5.2 Modification of Lignin 548
19.5.3 Lignin as Adhesive 552
19.5.4 Lignin as Sole Adhesive 554
19.5.5 Reactions of Lignin with Various Aldehydes and Other Naturally-Based Components 557
19.6 Summary 558
List of Abbreviations 558
References 559

20 Activation of Wood Surfaces and “Binderless” Wood Composites 579
Manfred Dunky
20.1 Introduction 579
20.2 Self-Adhesion and “Binderless” Boards 584
20.2.1 Wood and Non-Wood Components for “Binderless” Boards 586
20.2.2 Thermal and Physical Pretreatments of Wood Material and the Wood Surface 589
20.2.3 Chemical Treatments of the Wood Surface 591
20.2.4 Enzymatic Pretreatment of the Wood Surface 595
20.2.5 Degradation and Re-Polymerization of Carbohydrates 598
20.2.6 Citric Acid 601
20.2.6.1 Sugars and Starch in Combination with Citric Acid 601
20.2.6.2 Wood in Combination with Citric Acid 602
20.2.7 Hardboards (Wet Fiber Process) 605
20.2.8 Wood Welding 607
20.3 Summary 611
List of Abbreviations 611
References 612

21 Bonding of Solid Wood-Based Materials for Timber Construction 621
Peter Niemz and Manfred Dunky
21.1 Introduction 621
21.2 Brief Overview of Solid Wood-Based Materials 622
21.3 Adhesives Used for Materials in Structural Timber Engineering 625
21.3.1 Adhesives for the Production of Glued-Laminated Timber (Surface Bonding) 625
21.3.2 Casein Adhesives 628
21.4 Factors Influencing the Quality of Adhesively-Bonded Wood 631
21.4.1 Short Overview 631
21.4.2 Influence of the Wood Substrate (Structure and Wood Species) 631
21.4.3 Influence of Adhesives 636
21.4.4 Influence of Wood Machining 643
21.4.5 Quality Control of Bonded Wood Joints 644
21.4.6 Influence of Service Conditions 644
21.4.7 Aging of Bonded Wood 646
21.5 Trends in the Use of Biobased Adhesives 649
21.6 Summary 650
List of Abbreviations 651
References 652

22 Applications and Industrial Implementations of Naturally-Based Adhesives 659
Manfred Dunky
22.1 Introduction 659
22.2 Wood-Based Panels 660
22.3 Shoe Fabrication (Footwear Industry) 664
22.4 Bonding of Metals 666
22.5 Composites in Automotive, Aircraft, and Aeronautical Industries 667
22.6 Natural Composites with Matrices Based on Natural Resources 673
22.7 Mineral Wool 679
22.8 Packaging and Other Applications 679
22.9 Biomedical Applications 680
22.10 Biodegradability and Recycling 681
22.11 Life Cycle Analysis (LCA) 683
22.12 Summary 686
List of Abbreviations 686
References 688

23 Bioadhesives for the Advancement of Controlled Drug Delivery and Wearable Bioelectronics 705
Monalisha Ghosh Dastidar, Sharmili Roy and Sudarsan Neogi
23.1 Introduction 705
23.1.1 History of Bioadhesives and their Evolution 706
23.1.2 Classification of Bioadhesives 706
23.1.2.1 Natural Bioadhesives 707
23.1.2.2 Biological and Biocompatible Bioadhesives 707
23.1.2.3 Biomimetic and Bioinspired Bioadhesives 707
23.1.3 Mechanism of Bioadhesives 708
23.2 Bioadhesives in Controlled Drug Delivery 708
23.3 Bioadhesives in Bioelectronics 710
23.4 Limitations of Bioadhesives for Biomedical Applications 717
23.5 Summary and Future Prospects 718

List of Abbreviations 719
References 727