Rubber Recycling

by De; Sadhan K.

• ISBN13: 9780849315275
• ISBN10: 0849315271
• Edition: 1st
• Format: Hardcover
• Copyright: 2005-06-14
• Publisher: CRC Press

Summary

The safe disposal and reuse of industrial and consumer rubber waste continues to pose a serious threat to environmental safety and health, despite the fact that the technology now exits for its effective recycling and reuse. Mountains of used tires confirm the belief that chemically crosslinked rubber is one of the most difficult materials to recycle. That coupled with a long history of failed attempts to create quality products from crumb rubber has resulted in such a resistance to new ideas concerning rubber recycling that very little literature on the subject has even seen the light of day.Rubber Recycling is one of those rare books that has the potential to directly impact our ecological well-being. The editors of this important volume have filled a void in technological responsibility by bringing together a group of international experts who, using substantial research evidence, prove that the utilization of recycled rubber is not just desirable, but is also quite feasible and profitable.This text provides a thorough overview of the fundamentals of rubber and the challenges of recycling. However, the heart of the book lies in its detailed explanation of the various processes currently available to breakdown, recycle, and reuse crosslinked rubber. These include --· Unconventional polymer recycling· High-pressure, high-temperature sintering· Ultrasonic and non ultrasonic devulcanization· The use of tire particles as replacement aggregates for low-strength concrete material· The utilization of powdered rubber waste in the production of rubber compounds· The future potential for recycling waste rubber by blending it with waste plasticsNever forgetting that these technologies are meaningless without industry participation, the book concludes with a highly practical discussion on how present market demands can be met with recycled rubber.

Table of Contents

1 Manufacturing Practices for the Development of Crumb Rubber Materials from Whole Tires	1	(100)
Michael W. Rouse
1.1 Abstract	2	(1)
1.2 Background	3	(2)
1.3 The Tire	5	(5)
1.4 Other Sources of Tire-Shredding Components and Systems	10	(3)
1.4.1 Publications	10	(1)
1.4.2 Patents	11	(1)
1.4.3 Other Industries	12	(1)
1.4.4 Consultants, Brokers, and Equipment Manufacturers	12	(1)
1.5 Size Reduction Relationships	13	(2)
1.6 Applications	15	(10)
1.6.1 Tire-Derived Materials Applications	16	(5)
1.6.2 Civil Engineering Applications	21	(1)
1.6.3 Sanitation, Applications	22	(2)
1.6.4 Agricultural, Playground, and Decoration Applications	24	(1)
1.7 Testing and Quality Assurance	25	(7)
1.8 CRM Plant Demand	32	(1)
1.9 Support Equipment	33	(15)
1.9.1 Tire Compaction Units	34	(1)
1.9.2 Packaging	35	(1)
1.9.3 Transportation	36	(2)
1.9.4 Magnets	38	(2)
1.9.5 Magnetic Detectors	40	(1)
1.9.6 Pollution Control, Pneumatic Conveying, and Conventional Conveyors	41	(2)
1.9.7 Gravity Tables and Screening	43	(3)
1.9.8 Debeaders	46	(1)
1.9.9 Fire Suppressant Systems, Safety, and Storm Water Containment	46	(2)
1.9.10 Dirty Tire Cleanup	48	(1)
1.10 Primary Processing	48	(12)
1.10.1 Overview	48	(6)
1.10.2 Challenges in Processing Tires	54	(1)
1.10.3 Primary Reduction	55	(1)
1.10.4 The Cracker Mill	55	(1)
1.10.5 The Hammer Mill	56	(1)
1.10.6 The Rotary Shearer	57	(3)
1.11 Secondary Processing	60	(8)
1.11.1 The Two-Roll Mill or Grinder	60	(2)
1.11.2 Granulator Type Machines	62	(4)
1.11.3 The Cryo-Mill	66	(1)
1.11.4 The Extruder	66	(1)
1.11.5 High-Impact Air Mill	67	(1)
1.12 Tertiary Processing	68	(1)
1.12.1 Wet Mill	69	(1)
1.13 Major CRM Processes	69	(14)
1.13.1 Overview	69	(4)
1.13.2 Typical Ambient	73	(2)
1.13.3 Typical Cryogenic	75	(3)
1.13.4 Shear Extrusion Pulverization	78	(1)
1.13.5 Ambient Air Milling	79	(1)
1.13.6 Typical Wet Process	80	(3)
1.13.7 Other Processes	83	(1)
1.14 Overall Concept	83	(6)
1.14.1 Plant Design and General Process Considerations	84	(2)
1.14.2 Energy Requirements	86	(1)
1.14.3 Environmental and Safety Requirements	86	(1)
1.14.4 Preventive Maintenance	86	(1)
1.14.5 Custom Grinding	87	(2)
1.15 A Market-Driven Approach	89	(1)
1.16 Economics	89	(5)
1.17 Other Considerations	94	(3)
1.17.1 Energy Hierarchy of TDM	94	(1)
1.17.2 The Organization	94	(3)
1.18 Summary	97	(1)
References	98	(3)
2 Quality Performance Factors for Tire-Derived Materials	101	(26)
Michael W. Rouse
2.1 Abstract	102	(1)
2.2 Introduction	102	(5)
2.2.1 The Average, Standard, and Bound of Measurements	103	(1)
2.2.2 The TDM Challenge	103	(2)
2.2.3 Identifying the TDM	105	(1)
2.2.4 Tests for the Various CRM and TDM Materials	106	(1)
2.2.5 Contamination	106	(1)
2.3 The Tire Processor's Commitment	107	(3)
2.4 Management's Direction	110	(1)
2.5 Lean Manufacturing	110	(2)
2.6 Quality Assurance and Quality Control (Continual Improvement)	112	(3)
2.7 Analyzing the Outcomes	115	(2)
2.8 An Overall Strategy for Success and Perception	117	(5)
2.8.1 Chemical Characterization Methods	118	(3)
2.8.2 Other Methods	121	(1)
2.9 Implementation	122	(3)
2.9.1 A Suggested Approach	123	(2)
2.10 Summary and Conclusion	125	(1)
References	125	(2)
3 Untreated and Treated Rubber Powder	127	(28)
Wilma Dierkes
3.1 Introduction	128	(1)
3.2 Grinding Technologies	128	(7)
3.2.1 Cutting and Shearing	128	(3)
3.2.1.1 Cutting	128	(1)
3.2.1.2 Milling	129	(1)
3.2.1.3 Extrusion	129	(2)
3.2.1.4 Disk Grinding	131	(1)
3.2.1.5 Grinding in a Pellet Press	131	(1)
3.2.2 Grinding by Impact	131	(3)
3.2.2.1 Grinding in the Rubbery State (Ambient and Wet Grinding)	131	(1)
3.2.2.2 Grinding in the Glassy State (Cryogenic Grinding)	132	(2)
3.2.3 Grinding by Physical or Chemical Processes	134	(1)
3.3 Applications of Untreated Particulated Rubber	135	(7)
3.3.1 Rubber Products	135	(7)
3.3.1.1 Products from Pure Rubber Crumb	135	(1)
3.3.1.2 Products from Untreated Rubber Granulate and a Binder	136	(1)
3.3.1.3 Use of Untreated Rubber Powder in Rubber Compounds	137	(4)
3.3.1.4 Blends with Thermoplastic Materials (Polyblends)	141	(1)
3.4 Surface Treatment of Rubber Powder	142	(5)
3.4.1 Chemical Activation	142	(3)
3.4.1.1 Addition of a Polymer and/or a Curing System	142	(2)
3.4.1.2 Grafting	144	(1)
3.4.1.3 Swelling	144	(1)
3.4.1.4 Halogenation	144	(1)
3.4.2 Physical Activation	145	(1)
3.4.3 Microbial Treatment	145	(1)
3.4.4 Superfacial Devulcanization	146	(1)
3.5 Applications of Surface-Treated Rubber Powder in Rubber Products	147	(1)
3.6 Summary	148	(1)
References	149	(6)
4 Tire Rubber Recycling by Mechanochemical Processing	155	(34)
Klementina Khait
4.1 Introduction	155	(1)
4.2 Brief Review of Existing Tire Rubber Recycling Processes	156	(2)
4 3 Principles of Size Reduction	158	(2)
4.4 Mechanochemical Processes for Rubber Recycling	160	(22)
4.4.1 Elastic-Deformation Grinding (EDG)	160	(7)
4.4.1.1 Mechanism of EDG	161	(3)
4.4.1.2 Equipment for EDG	164	(3)
4.4.2 Solid-State Shear Extrusion (SSSE)	167	(2)
4.4.3 Developmental Tire Rubber/Plastic Composites	169	(7)
4.4.4 Solid-State Shear Pulverization (S³P)	176	(6)
4.5 Summary	182	(1)
References	183	(6)
5 Recycling Cross-Linked Networks via High-Pressure, High-Temperature Sintering	189	(24)
Richard J. Farris, Drew E. Williams, and Amiya R. Tripathy
5.1 Introduction	190	(1)
5.2 High-Pressure, High-Temperature Sintering	191	(18)
5.2.1 Brief History of Polymer Sintering	191	(1)
5.2.2 Schematic of Sintering Process	192	(1)
5.2.3 Influence of Molding Parameters on Mechanical Properties	192	(6)
5.2.3.1 Effect of Molding Temperature on Mechanical Properties	193	(2)
5.2.3.2 Effect of Molding Time on Mechanical Properties	195	(1)
5.2.3.3 Effect of Particle Size	196	(1)
5.2.3.4 Molding Parameter Conclusions	197	(1)
5.2.4 Influence of Rubber Backbone	198	(4)
5.2.4.1 Natural Rubber	198	(1)
5.2.4.2 Styrene-Butadiene Rubber	198	(2)
5.2.4.3 Polysulfide Rubber	200	(1)
5.2.4.4 Backbone Conclusions	200	(2)
5.2.5 Mechanism of Sintering: Bond Rupture and Reformation	202	(5)
5.2.5.1 Continuous Stress Relaxation	203	(1)
5.2.5.2 Intermittent Stress Relaxation	203	(1)
5.2.5.3 Correlation to Sintering	204	(1)
5.2.5.4 Time-Temperature Superposition	205	(1)
5.2.5.5 Mechanism Conclusions	206	(1)
5.2.6 Use of Additives to Increase Mechanical Properties	207	(8)
5.2.6.1 Reversion in Rubbers	207	(1)
5.2.6.2 Additive Results	207	(2)
5.3 Summary of High-Pressure, High-Temperature Sintering	209	(1)
References	209	(4)
6 Powdered Rubber Waste in Rubber Compounds	213	(34)
Ceni Jacob and S.K. De
6.1 Introduction	214	(1)
6.2 Grinding Method	214	(1)
6.3 Preparation of Powdered Rubber	215	(1)
6.3.1 Ambient Grinding	215	(1)
6.3.2 Cryogenic Grinding	215	(1)
6.3.3 Wet Grinding	216	(1)
6.3.4 Extrusion	216	(1)
6.3.5 Abrasion	216	(1)
6.4 Comparison of Grinding Techniques	216	(1)
6.5 Characterization of Powdered Rubber	217	(1)
6.6 Modifications of Ground Rubber	218	(3)
6.6.1 Surface Modification	219	(1)
6.6.1.1 By Mechanical Means	219	(1)
6.6.1.2 By Chemical Methods	219	(1)
6.6.1.3 Irradiation	219	(1)
6.6.2 Devulcanization	220	(32)
6.6.2.1 Using Chemical Probes	220	(1)
6.6.2.2 High-Energy Excitation	220	(1)
6.6.2.3 High-Shear Mixing	220	(1)
6.6.2.4 Microbial Desulfurization	220	(1)
6.6.2.5 High-Pressure Steam	220	(1)
6.7 Revulcanization of Powdered Rubber and Application of Revulcanizates	221	(1)
6.8 Mixing and Processing of Rubber Compounds Containing Powdered Rubber	221	(2)
6.9 Effect of Addition of Ground Rubber on the Rheological Behavior of Fresh Rubber Compounds	223	(3)
6.10 Effect of Addition of Ground Rubber on the Curing Characteristics of Fresh Rubber Compounds	226	(5)
6.11 Effect of Addition of Ground Rubber on the Mechanical Properties of Rubber Vulcanizates	231	(9)
6.12 Effect of Addition of Powdered Rubber on the Properties of Rubber Blends	240	(1)
References	241	(6)
7 Rubber Recycling by Blending with Plastics	247	(52)
D. Mangaraj
7.1 Introduction	247	(2)
7.2 Advantages of Rubber Recycling by Blending with Plastics	249	(2)
7.3 Compatibilization	251	(1)
7.4 Mechanical Compatibilization	252	(12)
7.4.1 Chemical Compatibilization	253	(1)
7.4.2 Nonreactive Compatibilization	253	(1)
7.4.3 Reactive Compatibilization	254	(6)
7.4.4 Surface Characteristics of Ground Rubber and Their Influence on GRT/Plastic Blends	260	(4)
7.5 Product and Process Development	264	(29)
7.5.1 Rubber-Thermoplastic Composites	264	(25)
7.5.1.1 Thermoplastic Elastomers	264	(13)
7.5.1.2 Roofing and Miscellaneous Products	277	(6)
7.5.1.3 Rheological Studies	283	(2)
7.5.1.4 Processes	285	(4)
7.5.2 Rubber-Thermoset Composites	289	(3)
7.5.3 Miscellaneous	292	(1)
7.6 Conclusions and Recommendations	293	(1)
References	294	(5)
8 Strategies for Reuse of Rubber Tires	299	(28)
D. Raghavan
8.1 Introduction	300	(1)
8.2 Disposal of Tires	301	(1)
8.3 Solutions to the Rubber Disposal Problem	302	(10)
8.3.1 Retreading and Splitting	302	(1)
8.3.2 Rubber Reclaiming	303	(1)
8.3.3 Pyrolysis	303	(1)
8.3.4 Tire-Derived Fuel	304	(1)
8.3.5 Reefs and Erosion Structures	305	(1)
8.3.6 Rubberized Asphalt	305	(2)
8.3.7 Rubberized Concrete	307	(5)
8.4 Rubber Treatment	312	(9)
8.5 Miscellaneous Applications	321	(1)
8.6 Summary	321	(1)
Acknowledgments	321	(1)
References	322	(5)
9 Ultrasonic Devulcanization of Used Tires and Waste Rubbers	327	(74)
A.I. Isayev and Sayata Ghose
9.1 Abstract	328	(1)
9.2 Introduction	328	(2)
9.3 Development of Technology	330	(4)
9.3.1 Introductory Remarks	330	(1)
9.3.2 Equipment	331	(2)
9.3.3 Application of Technology	333	(1)
9.4 Process Characteristics	334	(8)
9.4.1 Processing Parameters	334	(1)
9.4.2 Die Pressure and Power Consumption	335	(7)
9.4.2.1 Tire Rubber	335	(2)
9.4.2.2 Various Types of Rubbers	337	(5)
9.5 Cure Behavior	342	(4)
9.5.1 Tire Rubber	342	(1)
9.5.2 Various Types of Rubbers	343	(3)
9.6 Gel Fraction and Cross-Link Density	346	(7)
9.6.1 Tire Rubber	346	(2)
9.6.2 Various Types of Rubbers	348	(5)
9.7 Rheological Properties	353	(4)
9.7.1 Experimental Observations	353	(3)
9.7.2 Theoretical Description	356	(1)
9.8 Molecular Effect in Devulcanization	357	(8)
9.8.1 Sulfur-Cured Rubbers	357	(3)
9.8.2 Peroxide-Cured Rubber	360	(1)
9.8.3 Molecular Mobility and Diffusion	360	(5)
9.9 Mechanical Performance of Revulcanized Rubbers	365	(12)
9.9.1 Tire Rubber	365	(1)
9.9.2 Various Types of Rubbers	366	(8)
9.9.3 Blends of Devulcanized and Virgin Rubbers	374	(3)
9.10 Mechanisms of Devulcanization	377	(2)
9.10.1 Cavitation	377	(1)
9.10.2 Breakup of Cross-Links and Main Chains	378	(1)
9.11 Modeling of Ultrasonic Devulcanization Process	379	(15)
9.11.1 Cavitation Based on Elastic Model	379	(4)
9.11.2 Cavitation Based on Viscoelastic Model	383	(4)
9.11.3 Ultrasonic Power Consumption	387	(3)
9.11.4 Radical Depolymerization and Thermal Degradation	390	(4)
9.12 Conclusions	394	(1)
Acknowledgments	394	(1)
References	395	(6)
10 Devulcanization by Chemical and Thermomechanical Means	401	(1)
Marvin Myhre
10.1 Introduction	402	(1)
10.2 Devulcanization - Definition	403	(1)
10.3 Early Methods of Devulcanization	403	(3)
10.3.1 Thermal Process	404	(1)
10.3.2 Heater or Pan Process	404	(1)
10.3.3 Digester	404	(2)
10.4 Later Methods of Devulcanization	406	(6)
10.4.1 Thermal DevulcanizatiOn	406	(1)
10.4.2 Chemical Devulcanization	406	(2)
10.4.3 Mechanical Devulcanization	408	(1)
10.4.4 Chemomechanical Devulcanization	408	(3)
10.4.5 Thermomechanical Devulcanization	411	(1)
10.4.6 Thermochemical Devulcanization	412	(1)
10.5 Equipment	412	(2)
10.6 Materials and Chemicals	414	(1)
10.6.1 Digester: Alkali	414	(1)
10.7 Compounding with Devulcanized Rubber	415	(8)
10.8 Biotreatment	423	(1)
10.9 Abbreviations	424	(1)
Acknowledgments	424	(1)
References	425	(4)
11 Conversion of Used Tires to Carbon Black and Oil by Pyrolysis	429	(1)
C. Roy, A. Chaala, H. Darmstadt, B. de Caumia, H. Pakdel, and J. Yang
11.1 Abstract	429	(1)
11.2 Introduction	430	(3)
11.3 Vacuum Pyrolysis Process	433	(4)
11.3.1 Pyrolysis Yields	435	(2)
11.4 Properties of the Pyrolysis Products	437	(24)
11.4.1 Pyrolytic Carbon Black	437	(14)
11.4.1.1 Proximate and Elemental Analysis	437	(1)
11.4.1.2 Specific Surface Area and Structure	438	(1)
11.4.1.3 CBp Demineralization	439	(1)
11.4.1.4 CBp Surface Chemistry	440	(5)
11.4.1.5 CBp Applications	445	(6)
11.4.2 Pyrolysis Oil	451	(9)
11.4.2.1 Whole Oil	451	(3)
11.4.2.2 Oil Fractions	454	(6)
11.4.3 Pyrolysis Gases	460	(1)
11.4.4 Data on Economics	461	(1)
11.5 Conclusions	461	(1)
Acknowledgment	462	(1)
References	462	(7)
12 Markets for Scrap Tires and Recycled Rubber	469	(1)
Tjaart P. Venter
12.1 Introduction	470	(1)
12.2 Background	470	(1)
12.3 The Market in the U.S	471	(5)
12.4 The Market in Europe	476	(1)
12.5 Markets Elsewhere in the World	477	(1)
12.6 Market Analysis: The Practical Approach	478	(4)
12.6.1 Marketing's Four Ps	478	(1)
12.6.2 The Concept of Product/Service Value	479	(1)
12.6.3 The Value Tiers of Recycled Tires and Rubber	479	(2)
12.6.3.1 Tier 1: Substitute Virgin Rubber	479	(1)
12.6.3.2 Tier 2: Use Recycled Rubber for Its Rubber Character in Bound Systems	480	(1)
12.6.3.3 Tier 3: Flexible and Low-Cost Fillers	480	(1)
12.6.3.4 Tier 4: Use of Larger-Size Particles of Rubber	480	(1)
12.6.3.5 Tier 5: Whole Tires or Parts of Tires	480	(1)
12.6.3.6 Tier 6: Energy Value	481	(1)
12.6.4 Conclusion	481	(1)
12.7 Financial Evaluation: a Quick Reminder	482	(2)
12.7.1 Opportunity Cost	482	(1)
12.7.2 Payback Period	482	(1)
12.7.3 Net Present Value Method	483	(1)
12.7.4 Internal Rate of Return Method	483	(1)
12.8 Where to Get Market Information	484	(1)
12.9 A Handy List: Uses of Scrap Tires and Recycled Rubber	485	(1)
12.9.1 Tier 1: Substitute Virgin Rubber	485	(1)
12.9.2 Tier 2: Bound Systems Utilizing Rubber Characteristics of Recycled Rubber	485	(1)
12.9.3 Tier 3: Flexible and Low-Cost Fillers	485	(1)
12.9.4 Tier 4: Use of Larger-Size Particles of Rubber	486	(1)
12.9.5 Tier 5: Whole Tires or Parts of Tires	486	(1)
12.9.6 Tier 6: Energy Use	486	(1)
References	486	(1)
Further Suggested Reading and Contacts	487	(2)
Index	489