Rubbers energy

Designing With Elastomers, Rubber Energy Group. 

D. R. Matheson, Nitrile Compounding Symposium, presented at Rubber Energy Group, Sept. 1985. 

An alternative concept that is very relevant to our studies is that viscosity is a measure of the energy dissipated in flow The more viscous a fluid is, the more work (force X distance) has to be done to make it flow a given distance, and so the more energy is dissipated. This definition will allow us to compare and contrast liquid viscosity with rubber energy damping. 

This book defines specialty elastomers as heat-, oil-, fuel-, and solvent-resistant polymers. Each chapter examines individual elastomers in terms of development history, chemical composition, structure, and properties as well as processing methods, applications, and commercially available products. Covering their applications in the rubber, energy, chemicals, and oil industries, the book also discusses the use of antioxidants, antiozonants, vulcanization agents, plasticizers, and process aids for specialty elastomers. The concluding chapter details considerations and relevant processes—such as molding operations—involved in designing application-specific rubber components. 

L. D. Albia and M. M. Lynn, Chemistry of Elastomers Containing Vinylidene Fluoride, at the MCA Meeting of the Energy Rubber Group, Rubber Division, Educational Symposium, Arlington, Tex, Sept. 23, 1985, American Chemical Society, Washiagton, D.C. 

J. R. Dunn and G. C. Blackshaw, NBR—Chemistry andMarkets, at the MCA Energy Rubber Group Educational Symposium, Dallas, Tex, Sept. 24, 1985, American Chemical Society, Washington, D.C. 

NEMA WC3/1992 (ICEA S-19) Rubber insulated wire and cable for the transmission and distribution of electrical energy ... 

Figure 8.2 shows a non-linear elastic solid. Rubbers have a stress-strain curve like this, extending to very large strains (of order 5). The material is still elastic if unloaded, it follows the same path down as it did up, and all the energy stored, per unit volume, during loading is recovered on unloading - that is why catapults can be as lethal as they are. 

If you blow up a balloon, energy is stored in it. There is the energy of the compressed gas in the balloon, and there is the elastic energy stored in the rubber membrane itself. As you increase the pressure, the total amount of elastic energy in the system increases. 

To make the flaw grow, say by 1 mm, we have to tear the rubber to create 1 mm of new crack surface, and this consumes energy the tear energy of the rubber per unit area X the area of surface torn. If the work done by the gas pressure inside the balloon, plus the release of elastic energy from the membrane itself, is less than this energy the tearing simply cannot take place - it would infringe the laws of thermodynamics. 

It is clear from Table 27.1 that the energy content of the car itself - that is of the steel, rubber, glass and of the manufacturing process itself - is small less than one-tenth of that required to move the car. This means that there is little point in trying to save energy here indeed (as we shall see) it may pay to use more energy to make the car (using, for instance, aluminium instead of steel) if this reduces the fuel consumption. 

Other theories proposed dissipation of energy through crack interaction localised heating causing the material to be raised to above the glass transition temperature in the layers of resin between the rubber droplets and a proposal that extension causes dilation so that the free volume is increased and the glass transition temperature drops to below the temperature of the polyblend. 

The range of high-temperature rubbers is very small and limited to the silicones, already considered in this chapter, and certain fluororubbers. With both classes it is possible to produce polymers with lower interchain attraction and high backbone flexibility and at the same time produce polymers in which all the bonds have high dissociation energies and good resistance to oxidation. 

Chemicals are ubiquitous as air, carbohydrates, enzymes, lipids, minerals, proteins, vitamins, water, and wood. Naturally occurring chemicals are supplemented by man-made substances. There are about 70000 chemicals in use with another 500-1000 added each year. Their properties have been harnessed to enhance the quality of life, e.g. cosmetics, detergents, energy fuels, explosives, fertilizers, foods and drinks, glass, metals, paints, paper, pesticides, pharmaceuticals, plastics, rubber, solvents, textiles thus chemicals are found in virtually all workplaces. Besides the benefits, chemicals also pose dangers to man and the environment. For example ... 

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