Types of Elastomers

The elastomers that are listed here should be considered in light of their suitability for a specific application. The properties tables should serve as a guide to design options for those in the early stages of the development process. Keep in mind that these properties listed in the tables and the compatibility standings are only indicative of the performance characteristics that an elastomer may exhibit. 

Thermoplastic elastomers (TPEs) are a special class of materials that process similarly to other thermoplastic polymers, yet possess many of the 

Thermoplastic vulcanizates are a separate class of thermoplastic elastomers (TPEs) with Santoprene as the representative biomedical elastomer. 

Durometer Tensile Elonga- Modulus Tear Compres-Specific hardness strength, tion, ASTM strength sion set, 

Product ASTM ASTM ASTM ASTM------------------ ASTM ASTM 

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In order to "cure" or "vulcanize" an elastomer, ie, cross-link the macromolecular chains (Fig. 2), certain chemical ingredients are mixed or compounded with the mbber, depending on its nature (4,5). The mixing process depends on the type of elastomer a high viscosity type, eg, natural mbber, requires powerhil mixers (such as the Banbury type or mbber mills), while the more Hquid polymers can be handled by ordinary rotary mixers, etc (see Rubber... 

There are two major types of elastomer compression couplings. One is the torus type in which the elastomer is attached directly to the coupling hubs (see Figure 9-18). The other is the compression type with the elastomer held in compression by the hub geometry (see Figure 9-19). 

Table B.ll Properties of Various Types of Elastomer Compositions...

Compounds from solid fluorocarbon elastomers are mixed on the equipment common in the rubber industry. However, the mixing procedures typical for standard types of elastomers are often modified to be suitable for mixing fluorocarbon elastomers. 

Thermogravimetric analysis can yield a considerable amount of information about the composition of an elastomer system and is a common means of testing of EPDM rubber compounds [51]. The DTG curve may serve as an identifier of the type of elastomer in a compounded formulation. 

In view of the abundance of unsaturation in polydiene elastomers it may be expected that this type of elastomers can be cured very efficiently with peroxides. This section will show that a very high crosslinking efficiency (= moles of crosslinks formed per mole of peroxide decomposed) can indeed be obtained. However, the substitution pattern of the unsaturation plays a major role in the actual efficiency found. 

Elastomer technology is useful in medicine. Muscles and arteries contain giant molecules, called elastin, that make muscles and arteries contract. Doctors can give artificial arteries to people with severe heart problems or other diseases. Unfortunately these artificial arteries do not last long enough. Can they be replaced by a new type of elastomer ... 

The applications for this type of elastomer have been limited because of the melting point... 

Experiments—previously impossible without laser light scattering technology— suggested by this work involve studying the effect on physical properties of varying particle size for different types of elastomers. 

Properties (Type of elastomer) ABS (Polybutadiene ) ATS (ENB - EPDM ) (IID-EPTM ) ... 

Catalysts mentioned in this section are also utilised singly or at times in combination for the preparation of foams, sealants, coatings, adhesives and certain types of elastomers. 

Fig. 4 TIC from the GC/MS analysis of a methylene chloride extract from a second type of elastomer (compare with the TIC in Fig. 1).

This chapter addresses three basic classes of polymers and the approaches for processing them into compounds. These classes include thermoplastic polymers, and two types of elastomers -crosslinked elastomers, and thermoplastic elastomers. Compounds prepared from each class have a range of achievable properties, and each category of compounds may have overlapping properties. Each category is prepared by different technical approaches with varying controls, energy requirements, and limitations. A brief definition of each class follows. Also included, later in the chapter, is a detailed description of how additives influence the production process. 

Inorganic additives for rubber compounds also include materials that enhance performance under various accelerated stress conditions. Zinc oxide is an effective heat stabilizer for some types of elastomers. Iron oxide, lead compounds, barium salts, and specially treated clays, such as kaolinite, add performance margin in wet aging conditions. 

In this paper, we wish to report two different types of elastomer blends, ethylene-propylene-diene terpolymer/polyacety-lene and styrene-diene triblock copolymer/polyacetylene, in the hope that the stability of polyacetylene might be improved by... 

Historically, the bulk of urethanes and other plastics have been for interior seating and trim and for mechanical and electrical parts. With its first use in 1970, SMC was the major plastic used on the outside of the car. The promulgation of the Motor Vehicle Safety Standard 215, the bumper standard, resulted in an increase in the external uses of urethanes and other plastics. This resulted in the use of various types of elastomers for bumper sight shields, fender extenders and fascia. 

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