Section 4 Rubber Compounding Ingredients

Abbreviations of additive names can be foimd in the standard terminology (ASTM D1600-13 Standard Terminology for Abbreviated Terms Relating to Plastics). ISO standard has a separate section for symbols used for additives (ISO 1043-3 19% Plastics — Symbols and abbreviated terms — Part 3 Additives). In addition to the abbreviations for individual additives, Aimex A contains a hst of symbols for additive components (alcohol part, acid part, and other elements of composition). Abbreviations of additives used in rabber are given in a separate standard (ISO 6472 2010 Rubber compounding ingredients — Symbols and abbreviated terms). 

Consequently, this book has been compiled to be used as a quick reference. It includes a glossary of terms, tables of technical data, and, for those who require more detail, there are more comprehensive text sections covering the major rubber types, compounding ingredients and the equipment used in the most common processes. 

A compounding ingredient used to reduce the plasticity (increase the stiffness) of rubber compound and thus enable, e.g., an extruded section, to retain its shape or to reduce air trapping in moulding soft rubbers. 

Expectedly quantitative results vary considerably from one fiber-rubber system to another, and other compounding ingredients may induce additional effects (positive or negative). The qualitative effects are completely in line with the expected role of short fibers, in agreement with micromechanic considerations (see Section 7.2). Certain authors have used well established micromechanic approaches, e.g., Voigt and Reuss averages (Equations 7.1 and 7.2), and Halpin-Tsai equations (Equation 7.5) to consider the effects on short natural fibers in rubber compounds. ... 

The resistance of NBR to ageing in hot air is superior to that of natural rubber and polyisoprene. As will be seen (Section 6), much progress has been made in this respect in recent years by improving the choice of compounding ingredients and their ratios. Accordingly it is now possible to make NBR vulcanisates permanently resistant to hot air at about 90 °C. This means that they can be exposed continuously to air at this temperature for approximately 12 months. At 120°C a service life of about 40 days can be expected at 150°C it is likely to be about three days. 

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