Rubber and synthetic elastomers

Rubber and Synthetic Elastomers. For many years nondecorative coated fabrics consisted of natural mbber on cotton cloth. Natural mbber is possibly the best all-purpose mbber but some characteristics, such as poor resistance to oxygen and ozone attack, reversion and poor weathering, and low oil and heat resistance, limit its use to special appHcation areas (see Elastomers, synthetic Rubber, natural). 

RUBBER AND SYNTHETIC ELASTOMERS Table 18.6 Summary of elastomer properties... 

Phenan thro line (182) can be used instead of thiocyanate to form a complex with Fe(III) ions resulting from the oxidation of Fe(II), and the measurement is made at 500 to 510 nm. The use of 182 has the advantage of stability in the presence of air and also of allowing the use of hydrocarbon solvents for increased solubility of certain analytes. The method was applied for determination of hydroperoxides in natural rubber and synthetic elastomers, in the range of 10 to 20 ppm active oxygen. The sensitivity can be improved to less than 1 ppm, depending on the color of the sample solution. ... 

Guth E, James HM and Mark IT, "The Kinetic Theory of Rubber Elasticity", in Mark H and Whitby GS (Eds), "Scientific Progress in the Field of Rubber and Synthetic Elastomers" Interscience Publishers, New York, Vol. II, pp 253-299,1946. 

Ewart, R. H. Significance of viscosity measurements on dilute solutions of high polymers, Scientific Progress in the Field of Rubber and Synthetic Elastomers (Advances in Colloid Science) H. Mark and G. S. Whitby (Eds.), Vol. 2, pp. 197-251, Wiley-Interscience, New York, N.Y, 1946. 

Plasticizers today are used in commercially important amounts in about 35 different polymers with poly(vinyl chloride) (PVC) taking the largest share. Beyond the starting point in cellulosics, plasticizers have become highly important in poly(vinyl butyral), acrylic polymers (especially for surface coatings) and poly(vinyl acetate) (coatings and adhesives) and even in thermosets such as epoxies. Plasticizers are also used in crystalline polymers such as nylon, polypropylene, and poly(vinylidene chloride). Traditionally, extenders for rubber and synthetic elastomers were considered outside the field of plasticizers yet many such... 

Reaction with sensitizers, such as ketones and certain dyes, excited by radiation to their triplet states, results in the excited singlet state of oxygen, a very reactive form of the molecule. Singlet oxygen is responsible for the rapid deterioration of many materials, particularly those with conjugated unsaturation such as natural rubber and synthetic elastomers ... 

In the raw state elastomers tend to be soft and sticky when hot, and hard and brittle when cold. Compounding increases the utility of rubber and synthetic elastomers. Vulcanization extends the temperature range within which they are flexible and elastic. In addition to vulcanizing agents, ingredients are added to make elastomers stronger, tougher, or harder, to make them age better, to color... 

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