Polymer Blends and Composites

Muralisrinivasan Natamai Subramanian is a plastics technology consultant specializing in materials, additives, and processing equipment, including troubleshooting. The author obtained his BSc in Chemistry from the Madurai Kamaraj University and his MSc (1988) in Polymer Technology from Bharathiar University. He received his Post Graduate Diploma in Plastics Processing Technology from CIPET, Chennai. He has also completed his PhD in Polymer Science from Madurai Kamaraj University. He has worked in the plastic process industry, mainly in R & D, for 13 years before turning to consultancy and building up an international client base. Muralisrinivasan teaches plastics processing seminars as well as being a Board of Studies Expert Member of Colleges in India dealing with curriculum of technology subjects. He is also the author of two other Wiley-Scrivener books: The Basics of Troubleshooting in Plastics Processing (2011); and Plastic Additives and Testing (2013).

Preface xv

1 Introduction 1

1.1 Polymer Blends 2

1.2 Polymer Composites 2

1.3 Blends and Composites – Advantages 3

1.4 Summary 4

References 4

2 Polymers 7

2.1 Macromolecules 7

2.2 Types of Polymers 8

2.2.1 Thermoplastic Polymers 9

2.2.2 Thermoset Polymers 10

2.3 Polymerization 10

2.4 Polymerization Techniques 10

2.5 Synthetic Polymers 14

2.5.1 Thermoplastics 15

2.5.2 Polyolefins 16

2.5.3 Polyethylene (PE) 16

2.5.3.1 Physical Properties 17

2.5.3.2 Chemical Properties 18

2.5.3.3 Low-Density Polyethylene (LDPE) 19

2.5.3.4 Linear Low-Density

Polyethylene (LLDPE) 20

2.5.3.5 High-Density Polyethylene (HDPE) 21

2.5.3.6 Ultra-High Molecular Weight Polyethylene (UHMWPE) 22

2.5.4 Polypropylene (PP) 22

2.5.5 Polyvinylchloride (PVC) 23

2.5.5.1 Rigid PVC 24

2.5.6 Polystyrene (PS) 24

2.5.7 Polyethylene Terephthalate (PET) 25

2.6 Engineering Polymers 26

2.6.1 Acrylonitrile-Butadiene-Styrene (ABS) 27

2.6.2 Polyamide (PA) 28

2.6.3 Polycarbonate (PC) 29

2.6.4 Poly(methylmethacrylate) (PMMA) 30

2.6.5 Poly(ether ether ketone) (PEEK) 32

2.6.6 Poly(butylene terephthalate) (PBT) 33

2.7 Natural Polymers 33

2.7.1 Cellulose 34

2.7.2 Wood 34

2.7.3 Starch 35

2.7.4 Lignin 35

2.7.5 Chitosan 36

2.7.6 Poly(lactic acid) (PLA) 36

2.7.7 Poly(L-lactic acid) (PLLA) 37

2.8 Biodegradable Polymers 37

2.8.1 Poly(lactic acid) (PLA) 38

2.8.2 Polycaprolactone (PCL) 39

2.8.3 Poly(lactide-co-glycolide) (PLGA) 39

2.8.4 Thermosets 39

2.8.5 Phenolic Resins 40

2.8.6 Epoxy Resins 41

2.8.7 Polyurethanes 42

2.8.8 Silicone Resins 43

2.8.9 Amino Resins 43

2.8.10 Melamine Resins 43

2.8.11 Unsaturated Polyester Resins 43

2.8.12 Bismaleimide (BMI) 44

2.9 Trends 44

2.10 Summary 45

References 45

3 Polymer Properties 57

3.1 Chemistry 58

3.2 Polymer Properties 58

3.2.1 Glass Transition Temperature (Tg) 60

3.2.2 Crystallinity 61

3.2.3 Tacticity 63

3.2.4 Intermolecular Forces 63

3.2.4.1 Dipole Moment 64

3.2.4.2 Phase Behavior 64

3.3 Surface Properties 65

3.3.1 Viscoelastic Properties 65

3.3.2 Mechanical Properties 67

3.3.3 Tensile Properties 67

3.3.4 Electrical Properties 68

3.3.5 Thermal Properties 68

3.3.6 Magnetic Properties 68

3.3.7 Barrier Properties 69

3.3.8 Rheological Properties 69

3.3.9 Elastic Properties 69

3.3.10 Thermodynamic Properties 70

3.4 Catalysis 70

3.5 Factors Affecting Polymer Properties 71

3.6 Summary 72

References 72

4 Additives 77

4.1 Polymer Additives 77

4.2 Additives Influencing Blends and Composites 78

4.2.1 Antioxidants 78

4.2.2 Light Stabilizers 80

4.2.3 Heat Stabilizers 80

4.2.4 Plasticizers 81

4.2.5 Lubricants 83

4.2.6 Silp Additives 84

4.2.7 Antiblocking Additives 85

4.3 Processing Aids 85

4.3.1 Viscosity Modifiers 86

4.3.2 Accelerators 86

4.3.3 Mold Release Agents 87

4.3.4 Coupling Agents 87

4.3.5 Fillers 88

4.3.6 Flame Retardants 90

4.3.7 Antistatic Agents 91

4.3.8 Colorants 92

4.3.9 Antimicrobial Agents (Biocides) 92

4.3.10 Crosslinking Agents 93

4.3.11 Peroxides 94

4.3.12 Foaming Agents 95

4.3.13 Coupling/Dispersing Agents 96

4.3.14 Comonomers 97

4.3.15 Impact Modifiers 97

4.3.16 Natural Fibers 98

4.3.17 Copolymers as Additives 99

4.3.17.1 Compatibilizers 99

4.3.18 Interfacial Agents 100

4.3.18.1 Block Copolymers 101

4.3.18.2 Random Copolymer 103

4.3.18.3 Graft Polymers 103

4.4 Summary 104

References 104

5 Polymer Blends and Composites 113

5.1 Properties of Polymer Blends 114

5.1.1 Physicochemical Properties 115

5.1.2 Morphological Properties 116

5.1.2.1 Blend Structure 116

5.1.2.2 Phase Morphology 117

5.1.2.3 Crystallization and Morphology 119

5.1.2.4 Molecular Weight 120

5.1.2.5 Particle Size and Particle Size Distribution 121

5.1.3 Surface Properties 121

5.1.3.1 Surface Tension 121

5.1.3.2 Interfacial Modification 122

5.1.4 Rheological Properties 124

5.1.4.1 Copolymerization and Blending 125

5.1.5 Polymer Composite Properties 131

5.1.5.1 Structure 131

5.1.5.2 Crosslinking 133

5.1.5.3 Reinforcement 133

5.1.5.4 Crystalline Behavior 133

5.1.5.5 Mechanical Properties 134

5.1.5.6 Tribological Properties 134

5.1.5.7 Conductive Properties 135

5.2 Summary 135

References 136

6 Properties of Polymer Blends and Composites 145

6.1 Properties of Blends and Composites 146

6.1.1 Mechanical Properties 146

6.1.1.1 Tacticity 146

6.1.1.2 Interfacial Adhesion 147

6.1.1.3 Surface Composition and Concentration 147

6.1.2 Tensile Properties 149

6.1.3 Electrical Properties 149

6.1.4 Thermal Properties 149

6.1.5 Magnetic Properties 150

6.1.6 Viscoelastic Properties 150

6.1.7 Thermodynamic Properties 151

6.1.8 Barrier Properties 151

6.2 Summary 152

References 152

7 Polymer Blends 155

7.2.1 Interaction Parameters 157

7.2.2 Colloidal Properties 158

7.2.3 Morphology 158

7.2.4 Phase Separation 159

7.2.5 Crystallinity 159

7.2.6 Dispersion 160

7.2.7 Physicochemical Properties 160

7.3 Compatibilization 161

7.3.1 Reactive Compatibilizers 161

7.4 Classification 161

7.4.1 Miscible Blends 161

7.4.2 Immiscible Blends 162

7.4.3 Immiscible and Miscible Blends 163

7.4.4 Binary Blends 163

7.4.5 Ternary Blends 164

7.4.6 Homopolymer and Copolymer Blends 166

7.4.7 Thermoset-Thermoplastic Blends 166

7.4.8 Reactive Copolymer Blends 166

7.4.9 Commercial Blends 167

7.4.9.1 Polyolefin Blends 167

7.4.9.2 Polyethylene Blends 169

7.4.9.3 Polypropylene Blends 171

7.4.9.4 Poly(ethylene oxide) Blends 172

7.4.9.5 Polystyrene Blends 172

7.4.9.6 Polyvinylchloride Blends 173

7.4.9.7 Polyesters 175

7.4.9.8 Polyamide Blends 176

7.4.9.9 Acrylics Blends 178

7.4.10 Acrolonitrile-Butadiene-Styrene Blends 180

7.4.11 Polycarbonate Blends 181

7.4.12 Chlorinated Polyethylene Blends 182

7.4.13 Biopolymer Blends 183

7.4.13.1 Poly(lactic acid) Blends 183

7.4.14 Poly(ε-caprolactone) Blends 184

7.4.15 Cyclic Polymer Blends 184

7.4.16 Polyethylene Oxide Blends 184

7.4.17 Other Polymer Blends 185

7.5 Advantage of Polymer Blends 186

7.6 Summary 186

References 187

8 Polymer Composites 199

8.1 Polymeric Phase 200

8.2 Reinforcing Phase 200

8.3 Classification 200

8.4 Characteristics 201

8.4.1 Physical Properties 202

8.5 Reinforcing Agents 203

8.5.1 Advantages 203

8.5.2 Shortcomings 203

8.6 Fillers 203

8.6.1 Surface Modification 205

8.6.2 Boron Trinitride 205

8.6.3 Carbon Black 205

8.6.4 Mineral Fillers 206

8.6.4.1 Calcium Carbonate (CaCO3) 206

8.6.4.2 Mica 207

8.7 Fibers 207

8.7.1 Fiber Length 208

8.7.2 Synthetic Fibers 208

8.7.2.1 Carbon Fiber 208

8.7.2.2 Fiberglass 209

8.7.2.3 Aromatic Polyamide Fibers 210

8.8 Composites Classification 210

8.8.1 Mechanical Properties 211

8.8.2 Thermoplastic Composites 212

8.8.3 Filler Reinforced Polymeric Composites 212

8.8.4 Conducting Polymer Composites 212

8.8.5 Fiber Reinforced Composites 213

8.8.6 Continuous Fiber Composites 213

8.8.7 Discontinuous Fiber Reinforced Polymers 214

8.8.8 Carbon Fiber Reinforced Composites 214

8.9 Thermoset Composites 215

8.9.1 Advantages 216

8.10 Thermoplastic vs Thermoset Composites 216

8.11 Summary 217

References 218

9 Biocomposites 223

9.1 Natural Fillers 223

9.1.1 Wood Flour 224

9.2 Natural Fibers 224

9.2.1 Treatments of Natural Fibers 225

9.2.1.1 Silanes 225

9.2.1.2 Benzoylation and Acrylation 226

9.2.1.3 Coupling Agents 226

9.2.1.4 Dispersing Agents 226

9.2.2 Wood Fibers 226

9.2.3 Cellulosic Fibers 227

9.2.4 Other Natural Fibers 228

9.2.5 Shortcomings 228

9.3 Thermoplastic Materials 228

9.4 Natural Polymer Composites 228

9.5 Wood-Polymer Composites 229

9.5.1 Properties 230

9.5.2 Advantages 230

9.5.3 Disadvantages 231

9.5.4 Applications 231

9.6 Biocomposites 231

9.6.1 Glucose-Based Biocomposites 231

9.6.2 Polylactide Composites 232

9.7 Future Trends 232

9.8 Summary 233

References 233

10 Processing Technology 237

10.1 Processing Technology 237

10.2 Processing Requirements 238

10.3 Processing Polymer Blends 239

10.3.1 Devolatilization 239

10.3.2 Mixing 239

10.4 Selection of Polymers 240

10.4.1 Immiscible Polymer Blends 241

10.5 Machine Selection 241

10.6 Processing Polymer Composites 242

10.6.1 Melt Mixing 242

10.7 Thermoset Polymers 243

10.8 Processing Technology for Polymer Blends and Composites 243

10.8.1 Injection Molding 243

10.8.2 Extrusion Technology 246

10.8.2.1 Single Screw Extrusion 246

10.8.2.2 Twin Screw Extrusion 248

10.8.3 Thermoforming 250

10.8.4 Reactive Blending 252

10.8.4.1 Reaction Extrusion 253

10.8.4.1 Prepolymer 254

10.8.5 Curing 254

10.8.5.1 Autoclave Curing 254

10.8.6 Lay-Up and Spray-Up Techniques 255

10.8.7 Pultrusion 255

10.8.8 Sheet Molding Compound 256

10.8.9 Compression Molding 258

10.8.9.1 Shortcomings 260

10.8.10 Resin Transfer Molding 260

10.9 Wood-Polymer Composites 261

10.9.1 Injection Molding 262

10.9.2 Extrusion 262

10.9.3 Microcellular Foam Process 264

10.10 Recycling 266

10.11 Summary 267

References 268

11 Blends, Composites and the Environment 275

11.1 Recycling of Polymer Wastes 276

11.2 Polymer Blends and Composites Recycling 277

11.2.1 Pyrolysis 277

11.2.2 Energy Conversion 278

11.2.3 Recycling of Polymer Composites 278

11.2.4 Grinding 278

11.2.5 Reinforcing Agent Separation 280

11.3 Shortcomings 280

11.4 Present Needs 281

11.5 Future Commitment 282

References 282

12 Future Trends 285

12.1 Blends and Composites 286

12.2 Blend and Composite Requirements 286

12.3 Future Benefits 287

12.3.1 Automobile Applications 287

12.3.2 Aerospace Applications 287

12.3.3 High Strength Particle 287

12.3.4 Tribological Performance 287

12.4 Greener Processing 288

12.4.1 Use of Recycled Polymer 288

12.4.2 Present Trends 289

12.5 Future Trends 290

12.6 Summary 290

References 291