Understand the science of joining wood with this comprehensive guide
Long seen as an old-fashioned material with narrowing modern applications, wood has seen increased popularity as a material in building and manufacturing in recent years. This has been driven by the need for sustainable resources and environmentally friendly materials. As a result of increased emphasis on wood, however, there is a corresponding need to understand the wood adhesives, the crucial materials in wood-based manufacture and craftsmanship.
Adhesives and Finishes for Wood meets this need with a comprehensive but accessible introduction to the chemistry and applications of wood adhesives. Its easy-to-follow presentation nonetheless presents wood adhesives and finishes in significant detail. Ideal for readers without considerable preexisting knowledge in chemistry, this book includes everything the reader needs to understand and apply wood adhesives in their work or industry.
Adhesives and Finishes for Wood readers will also find: - Coverage ranging from the fundamentals of wood adhesive polymer chemistry to the properties of specific wood structures and resins - A presentation suitable for both academic students and wood manufacture professionals - An author with decades of experience in both academia and industry
Adhesives and Finishes for Wood is a useful reference for advanced students and professionals in industries or manufacturing disciplines that incorporate wood, as well as for chemists, materials scientists, vocational school instructors, and more.
Table of Contents
Preface xix
Author Biography xxi
1 Introduction to Polymers, Wood Adhesives, and Wood Finishes 1
1.1 Good Wood Adhesives Must Be Optimum Polymers with Optimum Secondary Forces 1
1.2 Polymeric Materials 2
1.3 Synthetic Polymer Preparation Methods 2
1.4 Typical Synthetic Polymer Materials 3
1.5 Typical Natural Polymers 8
1.6 Summary 10
References 11
2 Principles of Polymer Chemistry for Wood Adhesives and Finishes 12
2.1 Degree of Polymerization and Molecular Weight 12
2.1.1 Determination of Molecular Weight or Degree of Polymerization 12
2.2 Properties of Polymer Solutions or Suspensions 13
2.2.1 Viscosity of Polymer Solutions 13
2.2.2 Dependence of Viscosity on the Shear Rate (Stirring Rate) 14
2.2.3 Temperature Dependence of Viscosity of Polymer Solutions 15
2.2.4 Dependence of Viscosity on the Concentration and Molecular Weight of Dissolved Polymers 15
2.2.5 Methods of Viscosity Measurement of Liquid Materials 17
2.3 Polymer Solids Level and Specific Gravity of Polymer Solutions 18
2.4 pH of Polymer Solutions and Buffers 18
2.4.1 pH 18
2.4.2 Acidic Buffers and Buffer Capacity 19
2.5 Solid Properties of Polymer Materials 20
2.5.1 Adhesive Property of Polymer Solids 20
2.5.2 Cohesive Property of Adhesive Polymer Solids 20
2.5.3 Cohesive Strength Measurement and Viscous and Elastic Responses 20
2.5.4 Measurement of the Elasticity of Solid Polymer Materials 21
References 22
3 Thermosetting and Thermoplastic Wood Adhesives and Practices 23
3.1 Selection Criteria of Wood Adhesives 23
3.2 High Temperature-Curing Thermosetting Adhesives and Curing Conditions 24
3.3 Room Temperature-curing Thermosetting Wood Adhesives and Processes 25
3.4 Room Temperature-curing Thermoplastic Wood Adhesives 25
3.5 Adhesive Application Methods and Loading Rates and Costs 26
3.6 Adhesive Curing by Hot Presses and Other Heating Methods 26
3.7 Evaluation of Adhesive Bonds 28
3.8 Summary 28
References 28
4 Principles of the Curing of Thermosetting and Thermoplastic Wood Adhesives 29
4.1 Principles of Curing of Thermosetting Adhesive Resins at Elevated Temperatures 29
4.1.1 Viscosity Changes of Adhesive Layer Before Hot-Pressing 30
4.1.2 Spreading and Penetration of Adhesive Layers in Hot-Pressing 30
4.1.3 Viscosity Decreases by Moisture Content Changes 31
4.1.4 Viscosity Increases and Curing of Adhesive Layer by Polymerization Reaction 31
4.1.5 Flow and Wetting of Adhesive Layers and Molecular Adsorption 31
4.1.6 Gelation of Adhesive Layer 32
4.1.7 Vitrification of Adhesive Layer 32
4.1.8 Post-Curing of Adhesive Layer 33
4.2 Relationship of Temperature and Moisture Content in Hot-Pressing of Wood Composite Mats 33
4.2.1 Platen Pressure, Mat Thickness, and Density Profiles 33
4.2.2 Temperature Changes and Moisture Movements in Board Mat 34
4.2.3 Extents of Resin Cure in Hot-Pressing 35
4.3 Curing of Thermosetting Adhesives at Room Temperature 35
4.4 Curing of Thermoplastic Emulsion Adhesives 36
4.5 Volume Contractions of Adhesive Layers upon Curing 37
4.6 Thermal and Moisture Expansion/Contraction of Adhesive Layers 38
4.7 Summary 38
References 39
5 UF and MUF Wood Adhesive Resins (Manufacturing and Resin Chemistry) 40
5.1 Raw Materials of UF Resins 40
5.2 Urea-Formaldehyde (UF) Resins 42
5.3 Chemistry Occurring in UF Resin Synthesis 46
5.3.1 Second Step of Resin Synthesis 47
5.4 Polymer Chain Branching in UF Resins 50
5.5 Other Reactions Occurring in UF Resin Synthesis 52
5.6 F/U 1 Mole Ratio Effects in the Polymerization Step 53
5.7 Final F/U Mole Ratios and Formaldehyde Emission Problem 54
5.8 Physical and Chemical Tests and Properties of Industrial UF Resins 55
5.9 Resin Changes Occurring After Manufacture of UF Resins 58
5.10 Bond Performances and Durability Tests of UF Resins in Industry 60
5.11 UF Resins vs. Various Operating Parameters in PB, MDF, and Hardwood Plywood Industry 61
5.12 Other UF Resin Synthesis Procedures 62
5.13 Polymeric Chemical Structures of UF Resins 63
5.14 Melamine-Urea-Formaldehyde (MUF) Resins 63
5.15 Urea-Melamine-Formaldehyde (UMF) Resins 66
5.16 Summary 69
References 69
6 Urea-Formaldehyde and MUF/UMF Wood Adhesive Resins (Curing) 72
6.1 Typical Latent/External Catalysts Based on Ammonium Salts for UF Resins 72
6.2 Organic Tertiary Amine Salts of Strong Acids and Other Catalysts 73
6.3 Catalyzation of UF Resins by Wood Acids 74
6.4 Buffering of Acidic Catalysts 77
6.5 Thermosetting Curing Reactions, Cured Resin Structures, and Formaldehyde Emission Problem 78
6.6 Control of the Curing Speeds of UF Resins 81
6.7 Side-Reactions Occurring in the Curing of UF Resins 81
6.8 Phenomenological Changes of UF Resins in Curing 82
6.9 Chemical Curing Mechanisms, F/U Mole Ratio, and Cured Resin Structure 84
6.10 Composition of Cured UF Resins 85
6.11 Uses of UF Resins 86
6.12 Properties of UF Resin-Bonded Wood Composite Boards 86
6.13 Formaldehyde Emission Mechanisms, Mole Ratios, and Board Strength Properties 87
6.14 Various Methods Proposed/Practiced for Reducing the Formaldehyde Emissions of Boards 88
6.15 Curing of Melamine-Urea-Formaldehyde (MUF) Resins 89
6.16 Curing of Urea-Melamine-Formaldehyde (UMF) Resins 90
6.17 Cost Increases Estimated for Boards with Very Low Formaldehyde Emission Values 91
6.18 Summary 92
References 92
7 Particleboard, MDF, and Hardwood Plywood Bonding with UF Resin Binders 94
7.1 Particleboard 94
7.1.1 Wood Furnishes in Particleboard Manufacture 94
7.1.2 Blending of Resin, Catalyst, and Wax Emulsion in Particleboard Manufacture 95
7.1.3 Mat Formation and Transport 97
7.1.4 Hot-pressing 98
7.1.5 Equilibration and Finishing 100
7.1.6 Bison-Mende process 100
7.1.7 Properties of Commercial Particleboards 100
7.1.8 US Particleboard (PB) Industry 100
7.1.9 Summary 101
7.2 Medium Density Fiberboard (MDF) Bonded with UF Resins 102
7.2.1 Fiber Manufacture and Blowline Resin Blending 102
7.2.2 Paddle Blending System of Resins 104
7.2.3 Comparison of MDF Resin Blenders 105
7.2.4 Mat-Forming and Hot-Pressing Parameters of PB and MDF in Industry 107
7.2.5 Physical Properties of Commercial MDF 108
7.2.6 Medium Density Fiberboard Industry 109
7.2.7 Summary 109
7.3 Hardwood Plywood Bonding with UF Resin Adhesives 109
7.4 Paraffin Wax and Uses in Wood Composites 112
7.4.1 Use of Paraffin Wax 112
7.4.2 Properties of Paraffin Wax 112
7.4.3 Analyses of Wax 113
7.4.4 Wax Application Methods 114
7.4.5 Wax Use Levels 114
7.4.6 Summary 114
7.5 Effects of UF Resins’ Curing Catalysts on Tool Wear in Machining of Boards - An Example of Laboratory PB Manufacturing and Testing 115
7.6 Summary 120
References 120
8 PF Novolac Wood Adhesive Resins (Manufacturing and Chemistry) 122
8.1 Raw Materials of PF Resins 122
8.2 Reaction Chemistry of Phenol 123
8.3 Synthesis and Chemistry of Novolac Phenol-Formaldehyde (PF) Resins 124
8.4 Compounding and Curing of Novolac PF Resins 129
8.5 Curing Speed and Testing Methods of Molding Compounds of PF Novolac Resins 130
8.6 Wood Adhesive Uses of Novolac PF Resins 132
8.7 Summary 133
References 134
9 PF Resole Wood Adhesive Resins (Manufacturing and Chemistry) 136
9.1 Alkaline PF Resole Wood Adhesive Resins 136
9.2 Synthesis Chemistry and Manufacturing Practices of Alkaline PF Resole Resins 136
9.3 Typical Synthesis Procedures of Alkaline PF Resole Resins for Various Uses 140
9.4 Properties and Polymer Structures of Alkaline PF Resole Resins and Measurements 143
9.5 Resin Characteristics and Uses of Various PF Resole Resins 147
9.6 Molecular Weights (Sizes) of Alkaline PF Resole Resins and Wood Cell Wall Penetration 148
9.7 Powder PF Resole Resin Manufacturing by Spray-drying 149
9.8 Curing of Alkaline PF Resole Resins 150
9.8.1 Pre-dry and Pre-cure, Resin Spreading, and Flow 150
9.8.2 Final Curing of Alkaline PF Resole Resins in Wood Bonding 151
9.8.3 Gel Times and Stroke Cure Times of Liquid PF Resins 153
9.8.4 Dynamic Mechanical Analysis (DMA) Method of Curing Tests for Thermosetting Resins 153
9.8.5 Differential Scanning Calorimetric (DSC) Analysis of PF Resole Resins 157
9.9 Good Wood Adhesion and Exterior Durability of PF Resin Adhesives 158
9.10 Formaldehyde Emission Problem of PF Resin-bonded Products 159
9.11 Various Binder Uses of PF Resins in the US Wood Products Industry 159
9.12 Acid-curing PF and PMF Resole Resin and Dispersion Wood Adhesives 162
9.13 Summary 163
References 163
10 PRF Novolac Wood Adhesive Resins and Lumber Lamination 166
10.1 Manufacturing and Chemistry of PRF Resins 167
10.1.1 Chemical Structures of PRF Resins 169
10.1.2 Relationship Between Target Viscosity, Resin-Solids, and Storage Stability of PRF Resins 171
10.1.3 P/R Ratio Measurements from 13 C NMR Spectra 172
10.2 PRF and RF Resin Adhesives Currently Available in Industry 172
10.2.1 Some Nonideal Aspects of PRF Resins 173
10.3 Hardeners for PRF Resin Adhesives 174
10.4 Mixing of a PRF Resin and Hardener, Pot-Lives, Working Life, and Assembly Time 175
10.5 Applying and Curing of PRF Adhesives in Wood Lamination 176
10.6 Curing Chemistry of PRF Resin Adhesives and Industry Practices 179
10.7 Wood Lamination Industry 179
10.8 Recent Developments in PRF Resin Adhesives 182
10.9 Laminating Wood Adhesives Based on Other Resorcinolic Materials 184
10.10 Advanced Reading Materials on Resorcinol-Formaldehyde (RF) Resins 185
10.10.1 Synthesis and Fractionation of an RF Resin and GPC Analysis 185
10.10.2 Assignments of 13 C NMR Chemical Shift Values of RF Resin Fractions 187
10.10.3 Polymer Structures of RF Resins Derived from 13 C NMR Spectra 188
10.10.4 Relationship Between Intrinsic Viscosity and Molecular Weight Values from Equation n 3 190
10.11 Summary 191
References 191
11 Softwood Plywood Adhesives and Manufacturing Technology 194
11.1 Softwood Plywood Manufacturing Technology 194
11.2 PF Resole Resins for Bonding of Softwood Plywood 195
11.3 Veneer, Veneer Drying, and Adhesion Problems 196
11.4 Bond Performance Characteristics of Softwood Plywood Adhesives 197
11.5 Softwood Plywood Adhesive Mixing Procedure 197
11.6 Softwood Plywood Adhesive Formulation and Characteristics 198
11.6.1 Characteristics of PF Resin Adhesive Mixes 198
11.6.2 Gap-Filling Capability of Softwood Plywood Adhesives 199
11.6.3 Viscosity Targets of Softwood Plywood Adhesive Mixes 200
11.6.4 Fillers in Softwood Plywood Adhesives 200
11.6.5 Extenders in Softwood Plywood Adhesives 201
11.6.6 PF Resin Adhesives, Adhesive Spread Rates, and Application Methods 202
11.7 Open and Closed Assembly Times 204
11.8 Pre-pressing of Softwood Veneer Assembly 204
11.9 Hot-Pressing Parameters of Softwood Plywood 204
11.10 Laminated Veneer Lumber (LVL) 207
11.11 Parallel (Veneer) Strand Lumber (PSL) 207
11.12 New Developments in the Softwood Plywood Adhesive Technology 208
11.13 Phenolic Components Present in PF Resin-Bonded Softwood Plywood 209
11.14 Softwood Plywood Manufacturing Industry 209
11.15 Plywood Adhesive Fillers Made from Hydrolysis Residues of Municipal Newsprint Wastes 210
11.15.1 TVA Fillers and a Control Filler 210
11.15.2 Plywood Adhesive mix 211
11.15.3 Plywood Manufacture 211
11.15.4 Plywood Test Results 212
11.16 Conclusion 214
11.17 Summary 214
References 214
12 Isocyanate Wood Adhesive Resins 217
12.1 Chemical Compositions of Isocyanate Wood Adhesive Resins 217
12.2 Reactivity, Polymerization, and Curing Reactions of Isocyanate Resins 218
12.3 Mat Moisture Levels in Using pMDI Resins for OSB Bonding 223
12.4 Bond Properties and Uses of pMDI Resins as OSB Binders 224
12.5 pMDI Resins Used in Bonding of Other Wood Composite Products 226
12.6 Summary 227
References 227
13 OSB Manufacturing with PF and Isocyanate Wood Adhesive Resins 229
13.1 Oriented Strand Board (OSB) Manufacturing Processes 229
13.1.1 Wood Species Used in OSB Manufacture 229
13.1.2 Stranding (Flaking) 230
13.1.3 Drying and Screening of Strands 231
13.1.4 Binder Resin Types 231
13.1.5 Blending of Binder Resin and Slack Wax 232
13.1.6 Mat Forming with Strand Orienters 234
13.1.7 Hot-Pressing of Mat 235
13.1.8 Oriented Strand Lumber (OSL) 238
13.1.9 Adhesive Improvements Needed in the OSB Industry 239
13.1.10 History of Wafer Board and Flakeboard 239
13.1.11 Durability and Span Ratings of Oriented Strandboard in Use 239
13.2 OSB Bonded with PF Resins with Various Levels of Urea Added at the End of Resin Synthesis 240
13.2.1 Syntheses of PF Resole Resins with Urea Added at the End of Synthesis 241
13.2.2 Testing of Synthesized Resins 242
13.2.3 Resin Curing Rates Determined by DMA 242
13.2.4 Laboratory OSB Manufacturing and Testing 243
13.2.5 Test Results of Manufactured OSB Panels 244
13.2.6 Conclusion 246
13.3 Summary 246
References 247
14 Polyvinyl Acetate (PVAc) Emulsion Wood Adhesives 249
14.1 Polyvinyl Acetate (PVAc) Emulsion Wood Adhesive Resins 249
14.1.1 Manufacturing of PVAc Emulsion Resins 249
14.1.2 Properties of PVAc Emulsions and Polymers 250
14.1.3 Commercial PVAc Emulsions 250
14.1.4 Additives Used in Formulating PVAc Emulsion Wood Adhesives 251
14.1.5 Properties of Formulated PVAc Emulsion Wood Adhesives 252
14.1.6 Various Commercial Formulated PVAc Emulsion Wood Adhesives 252
14.1.7 Application Methods of PVAc Emulsion Wood Adhesives 253
14.1.8 Curing Mechanism of PVAc Emulsion Wood Adhesives 253
14.2 Summary 253
References 254
15 Troubleshooting in Wood Bonding with PVAc Resin Adhesives 255
15.1 Effects of Moisture Content of Wood 255
15.2 Troubleshooting Methods in Various Gluing Operations 259
15.2.1 Troubleshooting in Cold-Press Lamination 260
15.2.2 Troubleshooting in Hot-Press Laminating Process 260
15.2.3 Troubleshooting in Radiofrequency Edge-Gluing 261
15.2.4 Troubleshooting in Edge and Face Gluing by Clamping 261
15.2.5 Troubleshooting in Assembly Gluing by Clamping 262
Reference 262
16 Hot-melt and Other Specialty Wood Adhesives 263
16.1 Introduction to Hot-melt Adhesives 263
16.2 Requirements For Hot-melt Adhesives 263
16.3 Materials Used for Hot-melt Wood Adhesive Formulations 265
16.4 Advantages and Disadvantages of Hot-melt Adhesives 266
16.4.1 Advantages 266
16.4.2 Disadvantages 266
16.4.3 Uses of Hot-melts 267
16.5 Thermosetting Hot-melt Adhesives - Recent Development 267
16.5.1 A Typical Thermosetting Hot-melt Formulation 267
16.5.2 A Comparison of a Thermosetting Hot-melt Against Other Types 267
16.6 Key Variables in Hot-melt Edge-banding Operation 268
16.7 Other Specialty Wood Adhesives 269
16.7.1 Mastic Adhesives 269
16.7.2 Contact Adhesives 270
16.7.3 Epoxy Resin Adhesives 271
References 273
17 Casein, Soybean Flour, Animal Blood, and Lignin Wood Adhesives 275
17.1 Casein Wood Adhesives 275
17.2 Animal Protein-Based Wood Adhesive 276
17.3 Soybean Meal and Soybean Protein Wood Adhesives 276
17.4 Animal Blood-based Wood Adhesives 278
17.5 Various Lignins and Uses in Wood Adhesives 278
References 281
18 Theory and Practices of Adhesive Bonding for Wood 283
18.1 Formation of Interphase in Wood Adhesive Bonds and Failure Modes 283
18.1.1 Interphase Present Between Wood and Adhesive Layer in Adhesive Bond 283
18.1.2 Failure Modes in Mechanical Testing of Wood Bonds 284
18.1.3 Causes of Adhesive-layer or Interphase Failures in Wood Adhesive Bonds 284
18.1.4 Possible Further Divisions of Interphase in Wood Adhesive Bonds 285
18.1.5 Adhesive Failure vs. Wood Failure in Testing of Adhesive Bonds 285
18.1.6 Monitoring is a Must: Adhesive Quality, Adhesion Operation, and Bonded Products 286
18.2 Wettability of Solid Surface, Contact Angle, and Surface/Interface Tensions 287
18.3 Work of Adhesion 291
References 291
19 Physical and Chemical Mechanisms of Adhesive Bonding for Wood 292
19.1 Adsorption (Secondary Bond Forces) Theory of Adhesion 292
19.2 Mechanical Interlocking Theory of Adhesion 296
19.3 Diffusion Theory of Adhesion 297
19.4 Primary Chemical Bond (Covalent Bond) Theory 298
19.5 Summary of Adhesion Mechanisms 299
19.6 Glueline Layer Thickness and Bond Strengths 299
19.7 Summary 301
References 301
20 Evaluation of Wood Adhesive Bonds, Quality Control, and Bond Durability 302
20.1 Mechanical Testing Modes and Methods for Measuring the Adhesive Bond Strength 302
20.1.1 Shear Strength Test 302
20.1.2 Tensile Strength Tests 303
20.1.3 Cleavage and Peel Strength Tests 306
20.1.4 Bending Strength Tests 307
20.2 Quality Control, Certification Tests, and Adhesive Bond Durability 309
20.2.1 Objectives and Scope of Quality Control Processes 309
20.2.2 Durability Evaluation of Wood Composite Boards and Certification 309
20.2.3 Certification of Exterior-Use Wood Composite Products 310
20.2.4 Certification of Exterior-Use Wood-Based Structural Panels (PS2-92) 311
20.2.5 Cyclic Delamination Test Procedure (AITC Test 110) 312
20.2.6 Other Common Laboratory Aging Test Methods Used in the Industry 312
20.2.7 Testing and Certification Organizations Involved 313
20.3 Comparison of Various Wood Adhesive Bonds by Accelerated Aging or Exterior Exposure Tests 313
20.4 Nondestructive Testing of Wood and Wood Adhesive Bonds 315
20.5 In-situ Adhesion Testing 315
References 316
21 Introduction to Coatings Technology for Wood 317
21.1 Three Components of Coatings 317
21.2 Pigment Volume Concentration (PVC) 317
21.3 Various Kinds of Vehicle Polymers 319
21.3.1 Fatty Oils and Modified Fatty Oils 319
21.3.2 Alkyd Resins 320
21.3.3 Polyester - Unsaturated and Saturated Polyesters 321
21.3.4 Cellulosics 322
21.3.5 Acrylic Resins 323
21.3.6 Vinyl Resins 324
21.3.7 Epoxy Resins 325
21.3.8 Isocyanate Resins (urethane resins) 326
21.3.9 Silicone Resins 327
21.3.10 PF, MF, UF Resin Derivatives 327
References 328
22 Introduction to Coatings Technology for Wood. II 329
22.1 Pigments and Fillers 329
22.2 Manufacturing and Kinds of Pigments and Fillers 329
22.3 Color Control Methods 329
22.4 Color Scales - Hunter L, a, b, and CIE 1976 L*a*b* (CIELAB) Color Scales 331
22.5 Carriers of Coatings 332
22.6 Additives to Coatings 332
22.7 Manufacturing Procedures of Coatings 332
22.8 Film Formation Mechanisms 333
22.9 Water-Borne Coatings and Coatings for Less VOC Emissions 334
22.10 Exterior Coatings for Wood 336
22.10.1 Stains 336
22.10.2 Varnishes 336
22.10.3 Paints 337
22.11 Summary 337
References 338
23 Industrial Coating Application Processes 339
23.1 Application Methods of Coatings 339
23.2 Sanding Processes 342
23.3 Sanding Abrasives, Construction, and Flexing 344
23.4 Typical Furniture Finishing Procedures and Materials 344
23.5 Flat Line Finishing Procedures of Wood Composite Boards for Furniture Production 346
23.6 Kitchen Cabinet Finishing Procedures 347
23.7 Hardwood Plywood Panel Prefinishing 348
23.8 Hardboard Panel Finishing Procedures 349
23.9 Summary 350
References 350
24 Advanced Reading Materials on UF Wood Adhesive Resins 351
24.1 Introduction to the 13 C NMR Spectroscopic Analysis Method 351
24.2 Introduction to 13 C NMR Analysis Methods of UF and UMF Wood Adhesive Resins 356
24.3 13 c NMR Analysis Results of Reaction Intermediates Taken in UF Resin Syntheses 360
24.4 13 c NMR Analysis Results of Reaction Intermediates Taken in UF Resin Syntheses with a Higher Power Instrument 366
24.4.1 Effects of the Addition of Second Urea and Mild Heat Treatments 369
24.4.2 Polymerization in the Acidic Polymerization Step Observed with Second Urea Addition 370
24.4.3 Polymerization In the Acidic Reaction Step Observed Without the Second Urea Addition 372
24.4.4 Summary 373
24.5 Chemical Changes Occurring in UF Resins on heat/stirring and Room-temperature Storage Treatments by 13 C NMR and Formaldehyde Emission Tests of Particleboard 374
24.5.1 Effects of Mild and Intermediate Level Heat/Stirring Treatments (Samples A 2 -a 6) 374
24.5.2 Effects of Room-temperature Storage Treatments of UF Resins 378
24.5.3 Formaldehyde Emission Test Results of Particleboard (PB) 381
24.5.4 Summary 382
24.6 Effects of Mild Heating/Stirring Treatments on UF Resins Synthesized with Different F/U 1 Mole Ratios by 13 CNMR 382
24.6.1 Syntheses of UF Resins with Varying F/U 1 Mole Ratios 382
24.6.2 Heat/Stirring Treatments of Synthesized UF Resins 383
24.6.3 Viscosity and Turbidity Changes in Heat Treatments 383
24.6.4 F/U 1 Mole Ratio Effects on UF Resin Structures in Heat Treatments Observed by 13 CNMR 384
24.6.5 Summary 388
24.7 Effects of Room-temperature Storage Treatments on UF Resins Synthesized with Various F/U 1 Mole Ratios by 13 C NMR and Formaldehyde Emission Tests of Particleboard 388
24.7.1 F/U 1 Mole Ratio Effects on Viscosity/Turbidity Changes in Room-temperature Storage Treatments 389
24.7.2 Functional Group Changes of UF Resins in 7-50-day Room Temperature Storage 392
24.7.3 Test Results of Particleboards Bonded with Various UF Resins 393
24.7.3.1 Internal Bond and Bending Strengths of Particleboards (PBs) 393
24.7.3.2 F/U 1 Mole Ratio Effects on Formaldehyde Emission Values of Particleboards 394
24.7.4 Applications to the UF Resin and PB Manufacturing Industry 396
24.7.5 Summary 397
24.8 Effects of Mild Heat/Stirring and Room-temperature Storage Treatments of UF Resins Synthesized with Various F/U 1 Mole Ratios by 13 C NMR and Formaldehyde Emission Tests 397
24.8.1 Resin Synthesis and Treatment Procedures 398
24.8.2 Collection of Data 398
24.8.3 Heat Treatment Effects of UF Resins Made with Various F/U 1 Mole Ratios 402
24.8.4 Heat Treatments at 60 ∘ C for 2.5 hours Followed by Storage at Room Temperature for up to 27 days 405
24.8.5 Reaction Mechanisms of Methylene and Methylene-ether Group Forming Ractions 406
24.8.6 Viscosity and Phase Changes of UF Resins During Heating/Storage Treatments 408
24.8.7 F/U 1 Mole Ratio and Posttreatment Effects on Resin Polymeric Structures and Compositions 409
24.8.8 F/U 1 Mole Ratio and Heat Treatment Effects on Particleboard Strength Properties 411
24.8.9 Particleboards Bonded with Resins of 2.5-hours Heat and Followed Room-temperature Storage Treatments 415
24.8.10 Summary 417
References 418
25 Advanced Reading Materials on UMF Resins Modified with 6-12% Melamine 420
25.1 Introduction and Synthesis and Analysis Results of UF and UMF Resins 420
25.1.1 Background and Known Resin Synthesis Methods of UMF Resins 420
25.1.2 Reaction Chemistry of MF and UMF Resins 421
25.1.3 Resin Syntheses of UF and UMF Resins 422
25.1.4 characteristics of UMF Resins and Resin Intermediates Determined by 13 c NMR Spectra 422
25.1.5 General Resin Characteristics of Synthesized UMF Resins 429
25.1.6 Conclusion 432
25.2 DMA Curing Properties of UF and UMF Resins 432
25.2.1 Past Research Using Dynamic Mechanical Analysis (DMA) Method on Wood Adhesive Resins 432
25.2.2 DMA Sample Preparation and Experiments 433
25.2.3 Three Curing Segments of DMA Curing of Resin UFA 1.15 433
25.2.4 Curing Chemistry of Resin UFA 1.15 435
25.2.5 Effects of Catalyst Level and Mix Time and Temperature on DMA Curing of Resin UFA 1.15 438
25.2.6 Comparison of Resins UFA 1.15 and UMF 1.15 by DMA at Three Different Temperatures 439
25.2.7 Effects of Three Different F/(U + M) Mole Ratios on Curing Rates at 150 ∘ c 441
25.2.8 Summary 441
25.3 Bond Performance of UMF Resins as Particleboard Binders 443
25.3.1 Preparation and Tests of Laboratory Particleboards 443
25.3.2 Test results of Particleboards Bonded with Resins at an F/(U + M) Ratio of 1.15 443
25.3.3 Summary 445
References 445
26 Advanced Reading Materials on UMF Resins Modified with 2.5% and 5.0% Melamine 447
26.1 UMF Resins Synthesized with 2.5% and 5.0% Melamine Levels 447
26.1.1 Experimental Procedures 447
26.1.2 Resin Chemical Structures Determined by 13 C-NMR 449
26.1.3 Storage Stability of UF and UMF Resins 451
26.1.4 Properties of Catalyzed Resins 451
26.1.5 Particleboard Test Results 453
26.1.6 Summary 456
26.2 UMF Resins Synthesized by Adding Melamine at Different Points 456
26.2.1 Syntheses of UMF Resins 457
26.2.2 Physical Properties of Synthesized UMF Resins 458
26.2.3 Resins’ Chemical Structures From 13 C NMR Results 458
26.2.4 Storage Stability of Un-catalyzed Resins 459
26.2.5 Properties of Catalyzed UMF Resin 461
26.2.6 Particleboard (PB) Test Results 462
26.2.7 Summary 466
References 467
27 Advanced Reading Materials on Diethylene Tricarbamide-Formaldehyde Resins 468
27.1 Introduction 468
27.2 A Higher Functionality Urea Analogue - Diethylene Tricarbamide 469
27.3 Chemical and Physical Properties of Diethylene Tricarbamide 469
27.4 An Efficient Synthesis Method of Diethylene Tricarbamide 470
27.5 Synthesis Chemistry and Procedure and Properties of D-formaldehyde (DF) and Copolymer Resins 470
27.6 Synthesis Formulations of DF Resins vs. UF Resins 471
27.7 Room Temperature Storage Properties of DF and Copolymer Resins 472
27.8 Pot-lives and Curing Characteristics of DF and Copolymer Resins 472
27.9 Preparation of Laboratory Particleboards and Testing 473
27.10 Test Results of Prepared Laboratory Particleboards 473
27.11 Summary 475
References 475
28 Advanced Reading Materials on PF Resole Wood Adhesive Resins 476
28.1 Chemical Structures of PF Resole and Novolac Resins by 13 CNMR Spectroscopy 476
28.1.1 PF Resin Model Compounds 476
28.1.2 An Example Spectrum of a PF Resole Resin 479
28.1.3 A Second Example Spectrum of a PF Resole Resin 480
28.1.4 A Third Example 13 C NMR Spectrum of a Novolac PF Resin 480
28.1.5 Summary 481
28.2 Reaction Rates and Structures of a PF Resole Resin Synthesized at 70 ∘ c 482
28.2.1 Introduction 482
28.2.2 Peak Intensity Changes of Aromatic Carbons Due to Polymerization During Resin Synthesis 483
28.2.3 Peak Intensity Changes of Aliphatic Carbons due to Polymerization Reaction 484
28.2.4 Polymerization of PF Resole Resins Observed by Gel Permeation Chromatography (GPC) 487
28.2.5 Summary 488
28.3 Polymer Structures of a PF Resole Resin Synthesized at 102 ∘ C vs. a Commercial Resin 490
28.3.1 Introduction 490
28.3.2 Acetylation of PF Resin Samples and Fractionation 491
28.3.3 13 c NMR chemical Shift Values of Model compounds and PF Resin Fractions 492
28.3.4 13 c NMR Results of PF Resin Model compounds and Resin Fractions 492
28.3.5 Intrinsic Viscosity ([ŋ]), Vapor Phase Osmometric (VPO) Analysis, and M-H Equation 496
28.3.6 Conclusion 499
28.4 Polymer Structures of High Molecular Weight Fractions of a PF Resole Resin 500
28.4.1 Synthesis of an Oriented Strand Board Binder-type PF Resin and GPC Analysis 500
28.4.2 Acetylation and Fractionation 501
28.4.3 Instrumental Analyses of Acetylated PF Resin Fractions 501
28.4.4 Results and Discussion 502
28.4.5 Conclusion and Summary 508
28.5 Polymer Structures of Cured PF Resole Resins by Solid-state 13 CNMR 508
28.5.1 PF Resin Synthesis and Curing Procedures 508
28.5.2 Curing Mechanisms of PF Resole Resins and Loss of Some Formaldehyde? - a Review 510
28.5.3 Solid-state CP/MAS 13 C NMR Spectra 511
28.5.4 Solid-state CP/MAS 13 C NMR Chemical Shift Assignments of Aliphatic Carbons 511
28.5.5 Solid-state CP/MAS 13 C NMR Chemical Shift Assignments of Phenolic Ring Carbons 513
28.5.6 Solid-state CP/MAS 13 C NMR Chemical Shift Assignment of Quinone Structures 513
28.5.7 Results and Discussion 514
28.5.8 Conclusion and Summary 517
References 518
Index 521
