Poly(lactic acid)

List of Contributors xix Preface xxiii Author Biographies xxvii Part I Chemistry and Production of Lactic Acid, Lactide, and Poly(Lactic Acid) 1 1 Production and Purification of Lactic Acid and Lactide 3 Wim Groot, Jan van Krieken, Olav Sliekersl, and Sicco de Vos 1.1 Introduction 3 1.2 Lactic Acid 4 1.2.1 History of Lactic Acid 4 1.2.2 Physical Properties of Lactic Acid 4 1.2.3 Chemistry of Lactic Acid 4 1.2.4 Production of Lactic Acid by Fermentation 5 1.2.5 Downstream Processing/Purification of Lactic Acid 8 1.2.6 Quality/Specifications of Lactic Acid 10 1.3 Lactide 10 1.3.1 Physical Properties of Lactide 10 1.3.2 Production of Lactide 11 1.3.3 Purification of Lactide 13 1.3.4 Quality and Specifications of Polymer-Grade Lactide 14 1.3.5 Concluding Remarks on Polymer-Grade Lactide 16 References 16 2 Aqueous Solutions of Lactic Acid 19 Carl T. Lira and Lars Peereboom 2.1 Introduction 19 2.2 Structure of Lactic Acid 19 2.3 Vapor Pressure of Anhydrous Lactic Acid and Lactide 19 2.4 Oligomerization in Aqueous Solutions 20 2.5 Equilibrium Distribution of Oligomers 21 2.6 Vapor–Liquid Equilibrium 23 2.7 Density of Aqueous Solutions 25 2.8 Viscosity of Aqueous Solutions 25 2.9 Summary 26 References 26 3 Industrial Production of High-Molecular-Weight Poly(Lactic Acid) 29 Anders Södergård, Mikael Stolt, and Saara Inkinen 3.1 Introduction 29 3.2 Lactic-Acid-Based Polymers by Polycondensation 30 3.2.1 Direct Condensation 31 3.2.2 Solid-State Polycondensation 32 3.2.3 Azeotropic Dehydration 33 3.3 Lactic Acid-Based Polymers by Chain Extension 34 3.3.1 Chain Extension with Diisocyanates 34 3.3.2 Chain Extension with Bis-2-Oxazoline 36 3.3.3 Dual Linking Processes 36 3.3.4 Chain Extension with Bis-Epoxies 36 3.4 Lactic-Acid-Based Polymers by Ring-Opening Polymerization 37 3.4.1 Polycondensation Processes 37 3.4.2 Lactide Manufacturing 37 3.4.3 Ring-Opening Polymerization 39 References 40 4 Design and Synthesis of Different Types of Poly(Lactic Acid)/Polylactide Copolymers 45 Ann-Christine Albertsson, Indra Kumari Varma, Bimlesh Lochab, Anna Finne-Wistrand, Sangeeta Sahu, and Kamlesh Kumar 4.1 Introduction 45 4.2 Comonomers with Lactic Acid/Lactide 47 4.2.1 Glycolic Acid/Glycolide 47 4.2.2 Poly(Alkylene Glycol) 48 4.2.3 δ-Valerolactone and β-Butyrolactone 51 4.2.4 ε-Caprolactone 51 4.2.5 1,5-Dioxepan-2-One 52 4.2.6 Trimethylene Carbonate 52 4.2.7 Poly(N-Isopropylacrylamide) 52 4.2.8 Alkylthiophene (P3AT) 53 4.2.9 Polypeptide 53 4.3 Functionalized PLA 54 4.4 Macromolecular Design of Lactide-Based Copolymers 55 4.4.1 Graft Copolymers 57 4.4.2 Star-Shaped Copolymers 59 4.4.3 Periodic Copolymers 60 4.5 Properties of Lactide-Based Copolymers 62 4.6 Degradation of Lactide Homo-and Copolymers 63 4.6.1 Drug Delivery from Lactide-Based Copolymers 64 4.6.2 Radiation Effects 65 References 65 5 Preparation, Structure, and Properties of Stereocomplex-Type Poly(Lactic Acid) 73 Neha Mulchandani, Yoshiharu Kimura, and Vimal Katiyar 5.1 Introduction 73 5.2 Stereocomplexation in Poly(Lactic Acid) 73 5.3 Crystal Structure of sc-PLA 74 5.4 Formation of Stereoblock PLA 75 5.4.1 Single-Step Process 75 5.4.2 Stepwise ROP 76 5.4.3 Chain Coupling Method 77 5.5 Stereocomplexation in Copolymers 79 5.5.1 Stereocomplexation in Random and Alternating Lactic Acid or Lactide-Based Polymers 79 5.5.2 sc-PLA–PCL Copolymers 80 5.5.3 sc-PLA–PEG Copolymers 80 5.6 Stereocomplex PLA-Based Composites 81 5.7 Advances in Stereocomplex-PLA 82 5.8 Conclusions 83 References 83 Part II Properties 87 6 Structures and Phase Transitions of PLA and Its Related Polymers 89 Hai Wang and Kohji Tashiro 6.1 Introduction 89 6.2 Structural Study of PLA 89 6.2.1 Preparation of Crystal Modifications of PLA 89 6.2.2 Crystal Structure of the α Form 91 6.2.3 Crystal Structure of the δ Form 92 6.2.4 Crystal Structure of the β Form 93 6.2.5 Structure of the Mesophase 94 6.3 Thermally Induced Phase Transitions 95 6.3.1 Phase Transition in Cold Crystallization 95 6.3.2 Phase Transition in the Melt Crystallization 95 6.3.3 Mechanically Induced Phase Transition 96 6.4 Microscopically-viewed Structure-Mechanical Properties of PLA 98 6.5 Structure and Formation of PLLA/PDLA Stereocomplex 100 6.5.1 Reconsideration of the Crystal Structure 100 6.5.2 Experimental Support of P3 Structure Model 103 6.5.3 Formation Mechanism of Stereocomplex 104 6.6 PHB and Other Biodegradable Polyesters 106 6.6.1 Poly(3-Hydroxybutyrate) (PHB) 106 6.6.2 Polyethylene Adipate (PEA) 109 6.7 Future Perspectives 110 Acknowledgements 110 References 110 7 Optical and Spectroscopic Properties 115 Isabel M. Marrucho 7.1 Introduction 115 7.2 Absorption and Transmission of UV–Vis Radiation 115 7.3 Refractive Index 118 7.4 Specific Optical Rotation 119 7.5 Infrared and Raman Spectroscopy 119 7.5.1 Infrared Spectroscopy 120 7.5.2 Raman Spectroscopy 125 7.6 1H and 13C NMR Spectroscopy 127 References 131 8 Crystallization and Thermal Properties 135 Luca Fambri and Claudio Migliaresi 8.1 Introduction 135 8.2 Crystallinity and Crystallization 136 8.3 Crystallization Regime 140 8.4 Fibers 142 8.5 Commercial Polymers and Products 144 8.6 Degradation and Crystallinity 146 Acknowledgments 148 References 148 9 Rheology of Poly(Lactic Acid) 153 John R. Dorgan 9.1 Introduction 153 9.2 Fundamental Chain Properties from Dilute Solution Viscometry 154 9.2.1 Unperturbed Chain Dimensions 154 9.2.2 Real Chains 154 9.2.3 Solution Viscometry 155 9.2.4 Viscometry of PLA 156 9.3 Processing of PLA: General Considerations 158 9.4 Melt Rheology: An Overview 159 9.5 Processing of PLA: Rheological Properties 160 9.6 Conclusions 165 Appendix 9.A Description of the Software 166 References 166 10 Mechanical Properties 169 Mohammadreza Nofar, Gabriele Perego, and Gian Domenico Cella 10.1 Introduction 169 10.2 General Mechanical Properties and Molecular Weight Effect 170 10.2.1 Tensile and Flexural Properties 170 10.2.2 Impact Resistance 171 10.2.3 Hardness 172 10.3 Temperature Effect 172 10.4 Relaxation and Aging 173 10.5 Annealing 174 10.6 Orientation 176 10.7 Stereoregularity 179 10.8 Self-Reinforced PLA Composites 180 10.9 PLA Nanocomposites 180 10.10 Copolymerization 181 10.11 Plasticization 181 10.12 PLA Blends 182 10.13 Conclusions 186 References 186 11 Mass Transfer 191 Uruchaya Sonchaeng and Rafael Auras 11.1 Introduction 191 11.2 Background on Mass Transfer in Polymers 193 11.3 Mass Transfer Properties of Neat PLA Films 194 11.3.1 Mass Transfer of Gases 194 11.3.2 Mass Transfer of Oxygen 199 11.3.3 Mass Transfer of Water Vapor 201 11.3.4 Mass Transfer of Organic Vapors 203 11.4 Mass Transfer Properties of Modified PLA 205 11.4.1 PLA Stereocomplex and PLA Blends 206 11.4.2 PLA Nanocomposites 207 11.4.3 Other PLA Modifications 207 11.4.4 PLA in Other Forms 207 11.5 Final Remarks 208 Acknowledgments 208 References 208 12 Migration and Interaction with Contact Materials 217 Herlinda Soto-Valdez and Elizabeth Peralta 12.1 Introduction 217 12.2 Migration Principles 217 12.3 Legislation 218 12.4 Migration and Toxicological Data of Lactic Acid, Lactide, Dimers, and Oligomers 219 12.4.1 Lactic Acid 219 12.4.2 Lactide 224 12.4.3 Oligomers 225 12.5 EDI of Lactic Acid 226 12.6 Other Potential Migrants from PLA 227 12.7 Conclusions 227 References 228 Part III Processing and Conversion 231 13 Processing of Poly(Lactic Acid) 233 Loong-Tak Lim, Tim Vanyo, Jed Randall, Kevin Cink, and Ashwini K. Agrawal 13.1 Introduction 233 13.2 Properties of PLA Relevant to Processing 233 13.3 Modification of PLA Properties by Process Aids and Other Additives 235 13.4 Drying and Crystallizing 237 13.5 Extrusion 239 13.6 Injection Molding 241 13.7 Film and Sheet Casting 245 13.8 Stretch Blow Molding 249 13.9 Extrusion Blown Film 251 13.10 Thermoforming 252 13.11 Melt Spinning 254 13.12 Solution Spinning 258 13.13 Electrospinning 261 13.14 Filament Extrusion and 3D-Printing 265 13.15 Conclusion: Prospects of PLA Polymers 266 References 267 14 Blends 271 Ajay Kathuria, Sukeewan Detyothin, Waree Jaruwattanayon, Susan E. M. Selke, and Rafael Auras 14.1 Introduction 271 14.2 PLA Nonbiodegradable Polymer Blends 272 14.2.1 Polyolefins 272 14.2.2 Vinyl and Vinylidene Polymers and Copolymers 279 14.2.3 Rubbers and Elastomers 285 14.2.4 PLA/PMMA Blends 287 14.3 PLA/Biodegradable Polymer Blends 289 14.3.1 Polyanhydrides 289 14.3.2 Vinyl and Vinylidene Polymers and Copolymers 289 14.3.3 Aliphatic Polyesters and Copolyesters 297 14.3.4 Aliphatic–Aromatic Copolyesters 303 14.3.5 Elastomers and Rubbers 305 14.3.6 Poly(Ester Amide)/PLA Blends 307 14.3.7 Polyethers and Copolymers 307 14.3.8 Annually Renewable Biodegradable Materials 309 14.4 Plasticization of PLA 322 14.5 Conclusions 326 References 327 15 Foaming 341 Laurent M. Matuana 15.1 Introduction 341 15.2 Plastic Foams 341 15.3 Foaming Agents 342 15.3.1 Physical Foaming Agents 342 15.3.2 Chemical Foaming Agents 342 15.4 Formation of Cellular Plastics 343 15.4.1 Dissolution of Blowing Agent in Polymer 343 15.4.2 Bubble Formation 343 15.4.3 Bubble Growth and Stabilization 344 15.5 Plastic Foams Expanded with Physical Foaming Agents 344 15.5.1 Microcellular Foamed Polymers 344 15.5.2 Solid-State Batch Microcellular Foaming Process 345 15.5.3 Microcellular Foaming in a Continuous Process 353 15.6 PLA Foamed with Chemical Foaming Agents 358 15.6.1 Effects of CFA Content and Type 358 15.6.2 Effect of Processing Conditions 359 15.7 Mechanical Properties of PLA Foams 360 15.7.1 Batch Microcellular Foamed PLA 360 15.7.2 Extrusion of PLA 361 15.7.3 Microcellular Injection Molding of PLA 362 15.8 Foaming of PLA/Starch and Other Blends 362 References 363 16 Composites 367 Tanmay Gupta, Vijay Shankar Kumawat, Subrata Bandhu Ghosh, Sanchita Bandyopadhyay-Ghosh, and Mohini Sain 16.1 Introduction 367 16.2 PLA Matrix 367 16.3 Reinforcements 368 16.3.1 Natural Fiber Reinforcement 368 16.3.2 Synthetic Fiber Reinforcement 370 16.3.3 Organic Filler Reinforcement 370 16.3.4 Inorganic Filler Reinforcement 371 16.3.5 Laminated/Structural Composites 372 16.4 Nanocomposites 374 16.5 Surface Modification 375 16.5.1 Filler Surface Modification 375 16.5.2 Compatibilizing Agent 376 16.5.3 Composite Surface Modification 377 16.6 Processing 377 16.6.1 Conventional Processing 377 16.6.2 3D Printing 378 16.7 Properties 379 16.7.1 Mechanical Properties 379 16.7.2 Thermal Properties 382 16.7.3 Flame Retardancy 382 16.7.4 Degradation 383 16.7.5 Shape Memory Properties 383 16.8 Applications 384 16.8.1 Biomedical Applications 385 16.8.2 Packaging Applications 387 16.8.3 Automotive Applications 387 16.8.4 Sensing and Other Electronic Applications 388 16.9 Future Developments and Concluding Remarks 390 References 390 17 Nanocomposites: Processing and Mechanical Properties 411 Suprakas Sinha Ray 17.1 Introduction 411 17.2 Nanoclay-Containing PLA Nanocomposites 412 17.3 Carbon-Nanotubes-Containing PLA Nanocomposites 414 17.4 Graphene-Containing PLA Nanocomposites 416 17.5 Nanocellulose-Containing PLA Nanocomposites 417 17.6 Other Nanoparticle-Containing PLA Nanocomposites 418 17.7 Mechanical Properties of PLA-Based Nanocomposites 419 17.8 Possible Applications and Future Prospects 421 Acknowledgment 422 References 422 18 Mechanism of Fiber Structure Development in Melt Spinning of PLA 425 Nanjaporn Roungpaisan, Midori Takasaki, Wataru Takarada, and Takeshi Kikutani 18.1 Introduction-Fundamentals of Structure Development in Polymer Processing 425 18.2 High-speed Melt Spinning of PLLAs with Different d-Lactic Acid Content 426 18.2.1 Wide-angle X-ray Diffraction 426 18.2.2 Birefringence 427 18.2.3 Differential Scanning Calorimetry 428 18.2.4 Modulated-DSC and Lattice Spacing 429 18.3 High-speed Melt-Spinning of Racemic Mixture of PLLA and PDLA 430 18.3.1 Stereocomplex Crystal 430 18.3.2 Melt Spinning of PLLA/PDLA Blend 430 18.3.3 WAXD 431 18.3.4 Differential Scanning Calorimetry 432 18.3.5 In Situ WAXD upon Heating 432 18.4 Bicomponent Melt Spinning of PLLA and PDLA 433 18.4.1 Sheath-Core and Islands-in-the-Sea Configurations 433 18.4.2 Birefringence 434 18.4.3 DSC 434 18.4.4 Post Annealing 435 18.5 Concluding Remarks 436 References 437 Part IV Degradation, Environmental Impact, and End of Life 439 19 Photodegradation and Radiation Degradation 441 Wataru Sakai and Naoto Tsutsumi 19.1 Introduction 441 19.2 Mechanisms of Photodegradation 441 19.2.1 Photon 441 19.2.2 Photon Absorption 442 19.2.3 Photochemical Reactions of Carbonyl Groups 443 19.3 Mechanism of Radiation Degradation 443 19.3.1 High-Energy Radiation 443 19.3.2 Basic Mechanism of Radiation Degradation 444 19.4 Photodegradation of PLA 444 19.4.1 Fundamental Mechanism 444 19.4.2 Photooxidation Degradation 446 19.4.3 High-Energy Photo-Irradiation 447 19.4.4 Photosensitized Degradation of PLA 447 19.4.5 Photodegradation of PLA Blends 449 19.5 Radiation Degradation of PLA 449 19.6 Irradiation Effects on Biodegradability 451 19.7 Modification and Composites of PLA 452 References 452 20 Thermal Degradation 455 Haruo Nishida 20.1 Introduction 455 20.2 Thermal Degradation Behavior of PLLA Based on Weight Loss 455 20.2.1 Diverse Mechanisms 455 20.2.2 Factors Affecting the Thermal Degradation Mechanism 456 20.2.3 Thermal Stabilization 457 20.3 Kinetic Analysis of Thermal Degradation 458 20.3.1 Single-Step Thermal Degradation Process 458 20.3.2 Complex Thermal Degradation Process 459 20.4 Kinetic Analysis of Complex Thermal Degradation Behavior 460 20.4.1 Two-Step Complex Reaction Analysis of PLLA in Blends 460 20.4.2 Multistep Complex Reaction Analysis of Commercially Available PLLA 461 20.5 Thermal Degradation Behavior of PLA Stereocomplex: scPLA 463 20.6 Control of Racemization 464 20.7 Conclusions 465 References 465 21 Hydrolytic Degradation 467 Hideto Tsuji 21.1 Introduction 467 21.2 Degradation Mechanism 467 21.2.1 Molecular Degradation Mechanism 468 21.2.2 Material Degradation Mechanism 479 21.2.3 Degradation of Crystalline Residues 485 21.3 Parameters for Hydrolytic Degradation 488 21.3.1 Effects of Surrounding Media 488 21.3.2 Effects of Material Parameters 490 21.4 Structural and Property Changes During Hydrolytic Degradation 498 21.4.1 Fractions of Components 498 21.4.2 Crystallization 498 21.4.3 Mechanical Properties 499 21.4.4 Thermal Properties 499 21.4.5 Surface Properties 500 21.4.6 Morphology 500 21.5 Applications of Hydrolytic Degradation 500 21.5.1 Material Preparation 500 21.5.2 Recycling of PLA to Its Monomer 502 21.6 Conclusions 503 References 503 22 Enzymatic Degradation 517 Ken’ichiro Matsumoto, Hideki Abe, Yoshihiro Kikkawa, and Tadahisa Iwata 22.1 Introduction 517 22.1.1 Definition of Biodegradable Plastics 517 22.1.2 Enzymatic Degradation 517 22.2 Enzymatic Degradation of PLA Films 519 22.2.1 Structure and Substrate Specificity of Proteinase K 519 22.2.2 Enzymatic Degradability of PLLA Films 519 22.2.3 Enzymatic Degradability of PLA Stereoisomers and Their Blends 520 22.2.4 Effects of Surface Properties on Enzymatic Degradability of PLLA Films 521 22.3 Enzymatic Degradation of Thin Films 525 22.3.1 Thin Films and Analytical Techniques 525 22.3.2 Crystalline Morphologies of Thin Films 525 22.3.3 Enzymatic Adsorption and Degradation Rate of Thin Films 526 22.3.4 Enzymatic Degradation of LB Film 526 22.3.5 Application of Selective Enzymatic Degradation 529 22.4 Enzymatic Degradation of Lamellar Crystals 530 22.4.1 Enzymatic Degradation of PLLA Single Crystals 530 22.4.2 Thermal Treatment and Enzymatic Degradation of PLLA Single Crystals 532 22.4.3 Single Crystals of PLA Stereocomplex 533 22.5 Recent Advances in Characterization of Enzymes that Degrade PLAs Including PDLA and Related Copolymers 534 22.5.1 αβ-Hydrolase 535 22.5.2 Lipases and Cutinase-Like Enzymes 535 22.5.3 Polyhydroxyalkanoate Depolymerases 536 22.5.4 Enhancement of Biodegradability of PLAs 536 22.5.5 Control of Enzymatic Degradation of PLAs 537 22.6 Future Perspectives 537 References 537 23 Environmental Footprint and Life Cycle Assessment of Poly (Lactic Acid) 541 Amy E. Landis, Shakira R. Hobbs, Dennis Newby, Ja’Maya Wilson, and Talia Pincus 23.1 Introduction to LCA and Environmental Footprints 541 23.1.1 Life Cycle Assessment 541 23.1.2 Uncertainty in LCA 542 23.2 Life Cycle Considerations for PLA 542 23.2.1 The Life Cycle of PLA 542 23.2.2 Energy Use and Global Warming 544 23.2.3 Environmental Trade-Offs 544 23.2.4 Waste Management 545 23.2.5 End of Life 546 23.3 Review of Biopolymer LCA Studies 546 23.3.1 Cradle-to-Gate and Cradle-to-Grave LCAs 546 23.3.2 End-of-Life LCAs 547 23.4 Improving PLA’s Environmental Footprint 553 23.4.1 Agricultural Management 553 23.4.2 Feedstock Choice 554 23.4.3 Energy 554 23.4.4 Design for End of Life 555 References 555 24 End-of-Life Scenarios for Poly(Lactic Acid) 559 Anibal Bher, Edgar Castro-Aguirre, and Rafael Auras 24.1 Introduction 559 24.2 Transition from a Linear to a Circular Economy for Plastics 559 24.3 Waste Management System 561 24.4 End-of-Life Scenarios for PLA 564 24.4.1 Prevention and Source Reduction 565 24.4.2 Reuse 566 24.4.3 Recycling 566 24.4.4 Biodegradation 569 24.4.5 Incineration with Energy Recovery 572 24.4.6 Landfill 573 24.5 LCA of End-of-Life Scenario for PLA 574 24.6 Final Remarks 575 References 575 Part V Applications 581 25 Medical Applications 583 Shuko Suzuki and Yoshito Ikada 25.1 Introduction 583 25.2 Minimal Requirements for Medical Devices 583 25.2.1 General 583 25.2.2 PLA as Medical Implants 584 25.3 Preclinical and Clinical Applications of PLA Devices 585 25.3.1 Fibers 585 25.3.2 Meshes 588 25.3.3 Bone Fixation Devices 589 25.3.4 Micro-and Nanoparticles, and Thin Coatings 595 25.3.5 Scaffolds 597 25.4 Conclusions 598 References 598 26 Packaging and Consumer Goods 605 Hayati Samsudin and Fabiola Iñiguez-Franco 26.1 Introduction: Polylactic Acid (PLA) in Packaging and Consumer Goods 605 26.2 Food and Beverage 606 26.2.1 Evolution of PLA in the Food and Beverage Market 606 26.2.2 Growing Interest in PLA Serviceware 607 26.3 Distribution Packaging 612 26.4 Other Consumer Goods : Automotive 613 26.5 Other Consumer Goods 613 26.6 Challenges and Final Remarks 614 References 615 27 Textile Applications 619 Masatsugu Mochizuki 27.1 Introduction 619 27.2 Manufacturing, Properties, and Structure of PLA Fibers 619 27.2.1 PLA Fiber Manufacture 619 27.2.2 Properties of PLA Fibers and Textile 619 27.2.3 Effects of Structure on Properties 620 27.2.4 PLA Stereocomplex Fibers 621 27.3 Key Performance Features of PLA Fibers 621 27.3.1 Biodegradability and the Biodegradation Mechanism 621 27.3.2 Moisture Management 623 27.3.3 Antibacterial/Antifungal Properties 623 27.3.4 Low Flammability 624 27.3.5 Weathering Stability 624 27.4 Potential Applications 625 27.4.1 Geotextiles 625 27.4.2 Industrial Fabrics 625 27.4.3 Filters 626 27.4.4 Towels and Wipes 626 27.4.5 Home Furnishings 627 27.4.6 Clothing and Personal Belongings 627 27.4.7 3D-Printing Filament 628 27.5 Conclusions 628 References 628 28 Environmental Applications 631 Akira Hiraishi and Takeshi Yamada 28.1 Introduction 631 28.2 Application to Water and Wastewater Treatment 631 28.2.1 Application as Sorbents 631 28.2.2 Application to Nitrogen Removal 633 28.3 Application to Methanogenesis 637 28.3.1 Anaerobic Digestion 637 28.3.2 Methanogenic Microbial Community 637 28.4 Application to Bioremediation 638 28.4.1 Significance of PLA Use 638 28.4.2 Bioremediation of Organohalogen Pollution 638 28.4.3 Other Applications 639 28.5 Concluding Remarks and Prospects 640 Acknowledgments 641 References 641 Index 645