Contents 1. Biorefining and the Pulp and Paper Industry... 1 1.1 Introduction... 1 1.2 Biomass for Chemicals and Bioproducts... 3 1.2.1 Intracellular and Storage Materials... 3 1.2.1.1 Proteins... 3 1.2.1.2 Starch and Fructans... 3 1.2.1.3 Chlorophyll and Other Pigments... 3 1.2.2 Plant Cell Wall Components... 4 1.2.2.1 Cellulose... 4 1.2.2.2 Noncellulosic Polysaccharides... 4 1.2.2.3 Lignin... 5 1.2.2.4 Tannin and Other Polyphenols... 5 1.2.2.5 Lipids... 6 1.2.2.6 Cutin and Suberin... 6 1.2.2.7 Oil Crops... 7 1.2.2.8 Terpenes... 7 1.3 Possibilities of Biorefining Implementation into the Pulp Industry... 8 1.3.1 Lignin... 23 1.3.1.1 Separation of Lignin... 23 1.3.2 Degradation Products of Polysaccharides... 24 1.3.3 Black Liquor as a Feedstock for Synthesis Gas... 25 1.3.4 Separation of Hemicelluloses... 26 1.3.5 Fine and Speciality Chemicals... 27 xi
Pulp Production and Processing: From Papermaking to High-Tech Products 1.3.5.1 Bioactive Compounds... 28 1.4 Conclusions... 29 2. Pulping Fundamentals and Processing... 35 2.1 Introduction to Pulping... 35 2.2 Mechanical Pulping... 38 2.3 Semichemical Pulping... 42 2.4 Chemical Pulping... 43 2.5 Kraft Pulping Processes... 44 2.5.1 General Description... 44 2.5.2 Kraft Pulping Parameters... 49 2.5.3 Kraft Pulping Technology... 52 2.6 Sulfite Pulping... 56 2.7 Organosolv Pulping... 59 2.8 Conclusions or Future Trends... 61 3. Chemical Pulp Bleaching... 71 3.1 General Aspects... 71 3.2 Optical Properties of Pulp... 73 3.3 Residual Lignin and Other Oxidisable Structures... 75 3.4 Oxygen Delignification... 76 3.4.1 Chemistry of Oxygen Delignification... 77 3.4.2 Process Description and Variables... 80 3.4.3 Kinetics of Oxygen Delignification... 84 3.4.4 Process Technology and Equipment... 86 3.5 Chlorine Dioxide Bleaching... 89 3.5.1 Reactions and Factors in Chlorine Dioxide Bleaching... 89 3.5.2 Kinetic Dependencies of Chlorine Dioxide Bleaching... 91 3.5.3 Technology of Chlorine Dioxide Bleaching... 94 3.5.4 Reactions in the Extraction Stages... 95 3.6 Peroxide Bleaching... 96 xii
Contents 3.6.1 Chelating Stages... 96 3.6.2 Reactions and Factors in Hydrogen Peroxide Bleaching... 96 3.6.3 Process Variables and Technology of Peroxide Bleaching.. 97 3.6.4 Kinetics of Peroxide Bleaching... 101 3.6.5 Peracetic Acid in Pulp Bleaching... 102 3.7 Ozone Bleaching Chemistry and Technology... 104 3.8 Xylanases and Laccases in Pulp Bleaching... 105 3.9 Conclusions... 109 4. Oxygen Bleaching... 119 4.1 Introduction... 119 4.2 Advantages and Disadvantages of Oxygen Delignification... 120 4.3 Oxygen Production... 121 4.4 Delignification Chemistry... 122 4.4.1 Lignin Reactions... 122 4.4.2 Carbohydrate Reactions... 127 4.4.3 The Role of Hexenuronic Acids in Oxygen Delignification... 128 4.5 Mass Transfer and Reaction Kinetics... 129 4.6 Oxygen Delignification Technology... 131 4.6.1 Double-stage Medium-consistency Oxygen Delignification Systems... 134 4.7 Process Variables... 138 4.7.1 Pulp Washing... 138 4.7.2 Incoming Kappa Number... 139 4.7.3 Time and Temperature... 140 4.7.4 Reaction Pressure... 141 4.7.5 Oxygen Charge... 143 4.7.6 Alkali Charge... 143 4.7.7 Magnesium Charge... 146 4.7.8 Consistency... 147 xiii
Pulp Production and Processing: From Papermaking to High-Tech Products 4.8 Impact of Oxygen Delignification on Bleaching Effluent Quality. 147 5. Chemistry and Physics of Cellulose and Cellulosic Substances... 155 5.1 Introduction... 155 5.2 Basic Chemistry of Cellulose... 156 5.3 Supermolecular and Hypermolecular Characteristics of Cellulose and Lignocellulose Materials... 157 5.4 Water and Cellulose/Cellulosic Substances... 166 5.4.1 Liquid Crystalline Cellulose Suspensions... 166 5.4.2 Wet-web Strength and Wet Strength of Cellulosic Materials... 169 5.4.3 Interactions in Cellulosic Fibrous Slurries using Enthalpiometric Measurements... 170 5.4.3.1 Interpretation of Enthalpiometric Observations... 172 5.4.4 Existence of Water Inclusions among Cellulosic Chains.173 5.4.5 Hydrogel Structure of Cellulose... 174 5.5 H-bond Ability and Hydration Bonding/Antibonding Concept... 175 5.5.1 Rheosedimentation... 181 5.5.2 Thermoresponsive Hydrated Macro-, Micro- and Submicroreticular Systems of Cellulose... 182 5.5.3 Swelling... 187 5.6 Conclusions... 189 6. Physico-chemical Characterisation of Cellulose from the Broussonetia papyrifera Bark and Stem, and Eucommia Ulmoides Oliver Stem... 199 6.1 Introduction... 199 6.2 Experimental... 200 6.2.1 Materials... 200 6.2.2 Isolation of Cellulose... 201 6.2.3 Structural Characterisation of Cellulose... 202 6.3 Results and Discussion... 203 xiv
Contents 6.3.1 Yield of Cellulose... 203 6.3.2 Sugar Component Analysis... 204 6.3.3 Intrinsic Viscosity, Viscosity Average Degrees of Polymerisation and Molecular Weight... 206 6.3.4 Fourier Transform-infrared Spectra... 207 6.3.5 Cross Polarisation/Magic Angle Spinning 13 C Solid-state Nuclear Magnetic Resonance Spectra... 209 6.3.6 Thermal Analysis... 211 6.4 Conclusions... 212 7. Cellulose Fibres in the Papermaking Process... 217 7.1 Paper and Papermaking Raw Materials... 217 7.2 Suitability of Cellulose Fibres for Papermaking... 218 7.3 Are All Types of Fibres Equally Suitable for Papermaking?... 220 7.3.1 Papermaking Properties of Cellulose Fibres... 221 7.3.2 Chemical Composition... 221 7.3.3 Morphological Features of Fibres... 223 7.3.3.1 Fibre Length and Fines... 223 7.3.3.2 Cell Wall Thickness and Fibre Coarseness... 226 7.3.4 Wet Fibre Properties... 227 7.3.5 Dry Fibre Properties... 229 7.3.5.1 Effects of Drying Stress (Jentzen Effect)... 230 7.4 What happens to Cellulosic Fibres during Papermaking?... 231 7.4.1 Cellulose Fibres in the Slushing and Deflaking Processes.231 7.4.2 Swelling of Fibres... 234 7.4.3 Cellulose Fibres in the Refining Process... 236 7.4.4 Refining Effects on Fibres... 238 7.4.4.1 Removal of the Primary Fibre Wall... 238 7.4.4.2 External Fibrillation... 239 7.4.4.3 Internal Fibrillation... 239 7.4.4.4 Fibre Shortening... 239 xv
Pulp Production and Processing: From Papermaking to High-Tech Products 7.4.4.5 Creation of New Surfaces and Fines... 240 7.4.4.6 Partial Dissolution of the Fibre Wall... 240 7.4.4.7 Increase in Fibre Conformability... 240 7.4.4.8 Effects on Pulp Properties... 241 7.4.5 Cellulose Fibres in the Dewatering and Drying Processes... 241 7.5 Conclusions... 244 8. Cellulose Esters - From Traditional Chemistry to Modern Approaches and Applications... 253 8.1 Introduction... 253 8.2 Cellulose Esters: Heterogeneous or Cvasi-homogeneous Processes... 254 8.3 Cellulose Esters: Homogeneous Processes... 264 8.3.1 Dissolution of Cellulose... 264 8.3.1.1 Nonderivatising Solvents... 266 8.3.1.1.1 Aqueous Nonderivatising Solvents... 266 8.3.1.1.2 Nonaqueous Nonderivatising Solvents... 268 8.3.1.2 Derivatising Solvents... 270 8.3.2 Homogeneous Esterification of Cellulose... 271 8.4 Cellulose Esters in Nanotechnology... 277 8.5 Conclusions... 283 9. Lyocell Processes and Products... 299 9.1 Overview... 299 9.1.1 Reasons for a New Cellulose Fibre... 299 9.1.2 Lyocell/TENCEL Outline Profile... 300 9.2 TENCEL Development Timescale... 301 9.3 Process Description... 303 9.3.1 Pulp and Premix... 304 xvi
Contents 9.3.2 Dissolution Stage... 304 9.3.3 Solution Transport... 306 9.3.4 Filtration... 306 9.3.5 Spinning... 307 9.3.6 Fibre Washing... 307 9.3.7 Fibre Treatments... 308 9.3.8 Fibre Drying... 309 9.3.9 Crimping, Cutting and Baling... 309 9.3.10 Solvent Recovery... 310 9.3.11 Fibre Properties... 311 9.3.12 Environmental Factors... 311 9.4 Key Technological Factors... 312 9.5 Air Gap Spinning... 312 9.6 Safe Control of Reactions between Cellulose and N-methylmorpholine-N-oxide... 317 9.6.1 Chemical Reactions occurring in the Process... 317 9.6.2 Practical Solutions for Control of the Cellulose Reaction with N-methylmorpholine-N-oxide... 319 9.6.2.1 Cellulose Solution Temperature Control... 319 9.6.2.2 Pressure Relief to Accommodate an Exothermic Reaction... 320 9.6.2.3 Operation of Pumps used to Transport the Cellulose Solution... 321 9.7 Wood Pulp Requirements... 322 9.8 Control and Manipulation of Fibrillation... 324 9.8.1 Background... 324 9.8.2 What is Fibrillation?... 325 9.8.3 Approaches to Manipulation of Fibrillation... 327 9.8.4 Fibre Modification... 327 9.8.4.1 TENCEL A100... 328 9.8.4.2 TENCEL LF... 331 xvii
Pulp Production and Processing: From Papermaking to High-Tech Products 9.9 Dyeing and Finishing Technology Manipulation of Fibrillation.332 9.9.1 Using Fibrillation to give Peach Touch Fabrics... 332 9.9.2 Processing Routes to Making Peach Touch Fabrics... 333 9.9.3 Machinery Selection and Process Methodology... 334 9.9.3.1 Garment Processing... 335 9.9.3.2 Piece Dyeing... 335 9.10 Dyeing/Finishing Routes that Avoid Fibrillation... 336 9.11 TENCEL Conversion to Yarns and Fabrics... 337 9.12 TENCEL in Nonwovens... 337 9.13 TENCEL in Papers... 338 9.14 Conclusions... 340 10. Functional Cellulose Microspheres... 345 10.1 Introduction... 345 10.2 Challenges in the Dissolution of Cellulose... 346 10.2.1 Conventional Solvents... 347 10.2.2 Green Cellulose Solvents... 347 10.2.3 Pretreatments of Cellulose Fibres... 348 10.3 Preparation of the Microspheres using a Green Solvent Sodium Hydroxide-urea-water System... 350 10.3.1 Techniques for the Preparation of Microspheres... 350 10.3.2 Tailoring of Cellulose Microspheres using Physico-chemical Design... 352 10.4 Applications of Cellulose Microspheres... 353 10.4.1 Chromatography... 353 10.4.2 Protein Immobilisation... 354 10.4.3 Drug Loading and Release... 355 10.5 Conclusions... 355 11. Processing Cellulose Fibres to the Micron and Nanoscale... 361 11.1 Introduction... 361 xviii
Contents 11.2 Ultrastructure and Morphology of Cellulose Fibres... 362 11.3 Processing of Micro- and Nanocelluloses... 363 11.3.1 Processing of Microcrystalline Cellulose... 363 11.3.2 Processing of Cellulose Nanocrystals... 364 11.3.3 Processing of Micro/Nanofibrillated Cellulose... 367 11.3.4 Pretreatments... 369 11.4 Morphological Properties of Nanocelluloses... 370 11.5 Industrial Production of Micro- and Nanocelluloses... 373 11.6 Examples of Nanocellulose-based Materials... 374 11.6.1 Foams and Aerogels... 374 11.6.2 Films and Nanopapers... 375 11.6.3 Polymeric Nanocomposites... 375 11.7 Conclusions and Future... 377 12. Optical Properties of Cellulose Esters and Applications to Optical Functional Films... 391 12.1 Optical Properties of Polymeric Materials... 391 12.2 Wavelength Dispersion of Orientation Birefringence... 394 12.3 Orientation Birefringence of Cellulose Esters... 397 12.4 Advanced Methods to Control Orientation Anisotropy... 404 12.5 Conclusions... 408 13. Antibacterial Fibres... 413 13.1 A Brief Introduction... 413 13.2 Bacteria and Antibacterial Substances... 413 13.3 Cellulose as an Antibacterial Material... 416 13.4 Classification of Antibacterial Materials... 418 13.5 Fabrication of Leaching Materials... 420 13.5.1 Silver... 421 13.5.2 Triclosan... 421 13.5.3 Controlled Release of Antibacterial Substances... 423 xix
Pulp Production and Processing: From Papermaking to High-Tech Products 13.5.4 Leaching Natural Compounds... 424 13.6 Fabrication of Contact-active Materials... 425 13.6.1 Grafting of Polymers... 426 13.6.2 Adsorption of Polymers... 427 13.6.3 Other Approaches... 428 13.7 Testing of Antibacterial Fibres... 429 13.7.1 Available Standard Methods... 430 13.7.1.1 American Association of Textile Chemists and Colourists Standards... 431 13.7.1.2 Japanese Industry Standards... 431 13.7.1.3 American Society for Testing and Materials International Standards... 432 13.7.1.4 International Organization for Standardization... 432 13.7.1.5 Technical Association of the Pulp and Paper Industry... 433 13.7.1.6 SCAN Methods... 433 13.7.2 Methods for Contact-active Materials... 433 13.8 Final Remarks... 435 14. Recent Advances in the Processing of Biomass Feedstocks for Biohydrogen Production... 439 14.1 Introduction... 439 14.2 Biomass Pretreatment for Biohydrogen Production... 440 14.3 Biohydrogen Production with Processing of Sugar-rich and Mixed-composition Biomass... 448 14.4 Biohydrogen Production with Processing of Lignocellulosic Biomass... 456 14.5 Conclusions... 461 Abbreviation... 475 Index... 487 xx