Recycling of Polymers

Raju Francis is associate professor at Mahatma Gandhi University, Kottayam, India. He obtained his PhD degree in chemistry from NIIST (RRL-T), University of Kerala, India, in 1998 and completed his postdoc at the University of Bordeaux, France, and at the University of Florida, USA. He was an exchange visitor at Toyo University, Japan, and at King Abdullah University of Science & Technology, Saudi Arabia.His research interests include polymer-synthesis and applications, hybrid materials and environmental chemistry.

• Preface XIList of Contributors XVAbbreviations XVII1 Introduction 1Raju Francis, Geethy P. Gopalan, and Anjaly Sivadas1.1 Introduction 21.1.1 Why Recycling? 21.1.2 Sources ofWaste 21.1.3 Plastics 31.1.4 Recycling of Plastics 31.1.5 Municipal SolidWaste 41.1.6 Various Stages of Recycling PlasticWastes 61.1.7 Additives 61.1.8 Mixed Plastics 81.1.9 Composites 81.2 Conclusion 8References 92 Common Additives used in Recycling of Polymers 112.1 Review on Different Additives Used in Polymer Recycling 11Sivasankarapillai Vishnu Sankar and Sivasankarapillai Anil Kumar2.1.1 Introduction 112.1.1.1 Challenges in Recycling – Need for Additives 112.1.1.2 Equipment for Additive Processing 122.1.2 Different Types of Additives 122.1.2.1 Stabilizing Agents 142.1.2.2 Compatibilizers 192.1.2.3 Antioxidants 212.1.2.4 Impact Modifiers 232.1.2.5 Fillers and Modifiers 252.1.2.6 Antistatic Agents 262.1.2.7 Coloring Agents 262.1.2.8 Flame Retardants 272.1.2.9 Lubricants 282.1.2.10 Plasticizers 282.1.2.11 Antibacterial or Antimicrobial Additives 292.1.2.12 Coupling Agents 292.1.3 Conclusion 30References 302.2 Recent Trends and Future of Polymer Additives in Macromolecular Recycling Technology: A Brief Overview 31Sivasankarapillai Vishnu Sankar and Sivasankarapillai Anil Kumar2.2.1 Introduction 312.2.2 Miscellaneous Additives 322.2.2.1 Nucleating Agents 322.2.2.2 Reinforcing Agents or Fillers 332.2.2.3 Optical Brighteners 362.2.2.4 Surface Improvers 372.2.2.5 Antiblocking Additives 392.2.2.6 Blowing Agents (Foaming Agents) 392.2.2.7 Antifogging Agents 412.2.3 New Trends in Additives Technology 432.2.3.1 Advances in Stabilizers 462.2.3.2 Advances in Flame Retardants (FRs) 462.2.3.3 Advances in Plasticizers 472.2.3.4 Advances in Coloring Agents 472.2.3.5 Advances in Fillers 482.2.3.6 Advances in Other Additive Classes 482.2.3.7 Multifunctional Additives 492.2.4 Conclusion 49References 503 Methods of Recycling 553.1 Methods of Recycling of Polymers: Addition Polymers 55Beena Sethi3.1.1 Introduction 553.1.2 Primary Recycling 583.1.3 Mechanical Recycling (or Secondary Recycling) 583.1.4 Chemical or Feedstock Recycling (Tertiary Recycling) 593.1.5 Energy Recovery (Quaternary Recycling) 603.1.6 Chemical Recycling of Polyethylene (LDPE and HDPE) 623.1.6.1 Introduction 623.1.6.2 Thermolysis Schemes and Technologies 633.1.6.3 Reactor Types 653.1.7 Polyolefin Thermal Cracking 663.1.7.1 Catalytic Degradation 663.1.8 Chemical Recycling of Polypropylene 673.1.8.1 Introduction 673.1.8.2 Pyrolysis 693.1.8.3 Co-pyrolysis 703.1.8.4 Catalytic Cracking 713.1.9 Chemical Recycling of Polystyrene 753.1.9.1 Introduction 753.1.9.2 Recycling Methods for Polystyrene Products 763.1.9.3 Future Prospects 833.1.10 Chemical Recycling of Poly(vinyl chloride) 833.1.10.1 Introduction 833.1.10.2 Mixed Plastic Recycling Processes 863.1.10.3 Mixed PVCWastesWorld Initiatives 883.1.10.4 The BASF Feedstock Recycling Process 883.1.10.5 Veba Combi Cracking Process 903.1.11 Chemical Recycling of Poly(methyl methacrylate) 903.1.11.1 Introduction 903.1.11.2 Dissolution/Reprecipitation 913.1.11.3 Chemical/Feedstock Recycling 92References 933.2 Methods of Recycling of Polymers: Condensation Polymers 101Beena Sethi3.2.1 Introduction 1013.2.2 Chemical Recycling of Nylon 1013.2.2.1 Introduction 1013.2.2.2 Recycling Methods 1013.2.3 Chemical Recycling Involving Depolymerization of NylonsWhich Can Be Carried Out by Hydrolysis or Ammonolysis of Nylon 6,6 and Nylon 6 1023.2.3.1 Hydrolysis of Nylon 6 1023.2.3.2 Hydrolysis of Nylon 6,6 and Nylon 4,6 1033.2.3.3 Ammonolysis of Nylon 6,6 1033.2.3.4 Recovery of Nylon 6,6 Monomers 1043.2.3.5 Catalytic Pyrolysis 1053.2.3.6 Applications of Depolymerized Nylon 6 1053.2.4 Chemical Recycling of Polycarbonate 1053.2.4.1 Introduction 1053.2.4.2 Recycling Techniques 1063.2.5 Advantages of Recycling and Reuse of Polymers 110References 1124 Recycling of Plastics 115Preetha Balakrishnan and Meyyappallil Sadasivan Sreekala4.1 Introduction 1154.2 PlasticWaste Management Scenario 1174.3 Ways of Recycling 1194.3.1 Reuse 1204.3.2 Mechanical Recycling 1214.3.3 Chemical Recycling 1214.4 Poly(Lactic Acid) 1224.5 Poly(Vinyl Chloride) 1254.6 Polyethylene 1264.7 Polypropylene 1284.8 Polystyrene 1294.9 Poly(Ethylene Terephthalate) (PET) 1294.10 Applications 134References 1355 Recycling of Rubber 141Valiya Parambath Swapna and Ranimol Stephen5.1 Introduction 1415.2 Rubber 1425.3 Recycling of Rubber Products 1435.3.1 Chemical Process 1435.3.2 Physical Methods 1455.3.2.1 Mechanochemical Techniques 1455.3.2.2 Microwave Technique 1465.3.2.3 Ultrasonic Technique 1465.3.2.4 Twin-Screw Extruder 1485.3.3 Biological Process 1485.4 Applications of Recycled Rubber 1525.4.1 Sound-Insulation Materials 1525.4.2 Civil Engineering Applications 1535.4.3 Oil Absorbent 1545.4.4 Energy Production 1545.4.5 Zinc Fertilizer 1555.5 Concluding Remarks 155References 1566 Fibers 163Raju Francis, Nidhin Joy, Anjaly Sivadas, and Geethy P. Gopalan6.1 Introduction 1636.2 Natural Fibers 1646.2.1 Kenaf 1656.2.2 Cotton 1676.2.3 Sisal 1706.2.4 Asbestos 1746.3 Synthetic Fibers 1766.3.1 Nylon 1776.3.2 Polyester 1826.3.3 Glass Fiber 1876.3.3.1 Glass Fiber-Reinforced Plastics 1886.3.3.2 Mechanical Process 1886.3.3.3 Thermal Process 1886.3.3.4 Chemical Recycling 1906.3.4 Carbon Fiber 1926.3.4.1 Mechanical Recycling 1926.3.4.2 Thermal Recycling 1936.3.4.3 Chemical Recycling 1956.4 Conclusion 198References 1987 Recycling of Polymer Blends and Composites (Epoxy Blends) 209Jyothi V. Sunny7.1 Introduction 2097.2 Polymer Blends and Composites 2097.2.1 Methods of Recycling 2137.2.1.1 Mechanical Recycling 2137.2.1.2 Chemical Recycling 2157.2.1.3 Thermal Recycling 2167.3 Characterization and Application of Recyclates 2187.4 Conclusions 219References 2198 Recycling of Other Layered Mixed Plastics or Resins: Polyurethanes 223Jyothi V. Sunny8.1 Introduction 2238.2 Mechanical Recycling 2268.3 Chemical Recycling 2278.3.1 Glycolysis 2288.3.2 Hydrolysis 2298.3.3 Aminolysis 2298.4 Thermochemical methods 2308.4.1 Pyrolysis 2308.4.2 Gasification 2308.4.3 Hydrogenation 2308.5 Energy Recovery by Incineration 231References 2329 Ecoprofiles of Recycled Polymers at a Glance 2359.1 Advantages of Recycled Polymers on the Environment 235Raju Francis and Anjaly Sivadas9.1.1 Introduction 2359.1.2 Poly(ethylene terephthalate) (PET) 2369.1.3 High-Density Polyethylene (HDPE) 2379.1.4 Poly(vinyl chloride) (PVC) 2399.1.5 Polypropylene (PP) 2409.1.6 Polystyrene (PS) 2419.1.7 Other Polymers 2429.1.8 Conclusion 245References 2459.2 Toxic or Environmental Effects of Recycled Polymers 248Raju Francis, Nidhin Joy, and Anjaly Sivadas9.2.1 Introduction 2489.2.2 Will Recycling Reduce the Amount ofWaste? 2499.2.2.1 Recycling ofWaste Electrical and Electronic Equipment (WEEE) 2509.2.2.2 Recycling of Tires 2519.2.2.3 Recycling of Plastics 2519.2.2.4 Recycling of Polymers 2519.2.2.5 Health Problems 2529.2.2.6 Recycling by Polymer Incineration 2529.2.3 Conclusion 253References 253Index 257