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Elastomeric Materials ELASTOMERIC MATERIALS TAMPERE UNIVERSITY OF TECHNOLOGY THE LABORATORY OF PLASTICS AND ELASTOMER TECHNOLOGY Kalle Hanhi, Minna Poikelispää, Hanna-Mari Tirilä Summary On this course the students will get the basic information on different grades of rubber and thermoelasts. The chapters focus on the following subjects: - Introduction - Rubber types - Rubber blends - Thermoplastic elastomers - Processing - Design of elastomeric products - Recycling and reuse of elastomeric materials The first chapter introduces shortly the history of rubbers. In addition, it cover definitions, manufacturing of rubbers and general properties of elastomers. In this chapter students get grounds to continue the studying. The second chapter focus on different grades of elastomers. It describes the structure, properties and application of the most common used rubbers. Some special rubbers are also covered. The most important rubber type is natural rubber; other generally used rubbers are polyisoprene rubber, which is synthetic version of NR, and styrene-butadiene rubber, which is the most important sort of synthetic rubber. Rubbers always contain some additives. The following chapter introduces the additives used in rubbers and some common receipts of rubber. The important chapter is Thermoplastic elastomers. Thermoplastic elastomers are a polymer group whose main properties are elasticity and easy processability. This chapter introduces the groups of thermoplastic elastomers and their properties. It also compares the properties of different thermoplastic elastomers. The chapter Processing give a short survey to a processing of rubbers and thermoplastic elastomers. The following chapter covers design of elastomeric products. It gives the most important criteria in choosing an elastomer. In addition, dimensioning and shaping of elastomeric product are discussed The last chapter Recycling and reuse of elastomeric materials introduces recycling methods. It also covers processing of recycled rubber and applications of waste rubber. After studying this course, the students have the basic information on different grades of rubber and thermoplastic elastomers. They will know the recycling practices of rubbers and they will understand the design practices of elastomeric materials. ©TUT 2007 2 Table of contents Summary....................................................................................................................2 Table of contents........................................................................................................3 1. Introduction to elastomeric materials ................................................................5 1.1 Definitions of elastomeric materials and rubbers ..........................................6 1.2 Manufacturing process of rubbers .................................................................7 1.3 Behaviour of elastomers ................................................................................8 1.4 General properties of elastomers ...................................................................9 2. Classification of elastomers.............................................................................14 2.1 Natural Rubber (NR) ...................................................................................16 2.2 Isoprene Rubber, Polyisoprene (IR) ............................................................18 2.3 Butadiene Rubber, Polybutadiene (BR) ......................................................20 2.4 Styrene-Butadiene Rubber (SBR)................................................................23 2.4.1 The use of SBR in tyres........................................................................26 2.5 Butyl Rubbers ..............................................................................................27 2.6 Nitrile Rubber, Nitrile-Butadiene Rubber, Acrylonitrile Rubber (NBR)....29 2.6.1 Modified nitrile rubbers........................................................................30 2.7 Epichlorohydrin Rubbers.............................................................................31 2.8 Ethylene-Propylene Rubber (EPM), Ethylene-Propylene-Diene Rubber (EPDM)................................................................................................................32 2.8.1 Typical Properties.................................................................................33 2.9 Chloroprene Rubber, Polychloroprene (CR) ..............................................35 2.10 Polyacrylate Rubbers (ACM) ....................................................................37 2.11 Polyurethane rubbers (AU, EU, PUR).......................................................38 2.12 Fluorocarbon Rubbers (FKM, FPM) .........................................................41 2.13 Silicone Rubbers (Q) .................................................................................44 2.14 Polysulphide Rubbers (T)..........................................................................46 2.15 Ethylene-Vinyl Acetate Copolymer (EVA)...............................................47 2.16 Polypropylene Oxide Rubbers, Polypropylene Oxide-Allyl Glycidyl Ether Copolymer (GPO)................................................................................................48 2.17 Chlorinated Polyethylene (CM, CPE), Chlorosulphonated Polyethylene (CSM, CSPE).......................................................................................................49 3. Rubber blends ..................................................................................................50 4. Thermoplastic elastomers (TPE) .....................................................................51 4.1 Styrenic thermoplastic elastomers (TPE-S).................................................52 4.2 Elastomeric alloys........................................................................................53 4.2.1 Thermoplastic Olefin Elastomers (TPO, TOE) ....................................53 4.2.2 Thermoplastic Vulcanizates (TPE-V, TPV, DVR)...............................54 4.2.3 Melt-Processible Rubbers (MPR).........................................................55 4.3 Thermoplastic Urethane Elastomers (TPU, TPE-U) ...................................55 4.4 Thermoplastics Polyester-Ether Elastomer (TPE-E)...................................57 4.5 Thermoplastic Polyamide Elastomers (TPE-A) ..........................................58 4.6 Comparison of different TPEs.....................................................................59 4.7 New development trends occuring in the field of TPEs ..............................59 5. Processing........................................................................................................60 5.1 Processing of rubbers...................................................................................60 5.2 Processing of thermoplastic elastomers.......................................................60 ©TUT 2007 3 6. Design of elastomeric products .......................................................................61 6.1 Design process...............................................................................................63 6.2 Elastomer selection......................................................................................63 6.3 Dimensioning of elastomer products...........................................................65 6.3.1 Mechanical dimensioning.....................................................................65 6.3.2 The influence of hardness.....................................................................65 6.3.3 Shape factor ..........................................................................................65 6.3.4 Stiffness in different loading situations ................................................66 6.3.5 Allowed loadings for different rubbers.................................................67 6.4 Product shaping ...........................................................................................69 7. Comparison of Elastomer Properties. Data sources ........................................70 8. Recycling and reuse of elastomeric materials .................................................74 8.1 Why reclaim or recycle rubber? ..................................................................74 8.2 Recycling methods.......................................................................................75 8.2.1 Incineration...........................................................................................75 8.2.2 Pyrolysis ...............................................................................................76 8.2.3 Grinding of vulcanized rubber waste....................................................76 8.2.4 Devulcanization ....................................................................................78 8.3 Utilization of unvulcanized rubber waste....................................................80 8.4 Processing of recycled rubber......................................................................80 8.4.1 Unvulcanized rubber waste...................................................................80 8.4.2 Vulcanized rubber waste.......................................................................80 8.4.3 Devulcanized rubber waste...................................................................81 8.5 Applications of waste rubber.......................................................................82 8.6 Recycling of tyres........................................................................................82
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