Abstract

Rubber chemicals are materials that are added in minor amounts to rubber formulations in order to improve their properties and make them commercially useful. Raw rubber polymer has very limited practical applications because of tackiness, flow, and other undesirable features. Rubber chemicals are added to assist processing, promote cross-linking, and provide longevity to the part in service. Vulcanizing adjacent polymer chains together by cross-links prevents flow, increases strength, and provides recovery from deformation. The most widely used method of cross-linking polymer chains is by heating with elemental sulfur (vulcanization). Accelerators speed up the reaction of sulfur with polymer to improve the economics of manufacture and prevent degradation that would otherwise occur upon prolonged heating. Peptizers and process aids assist flow during the mixing and shaping operations. Antidegradants protect the part in service from heat, oxygen, ozone, and repeated flexing. Other rubber chemicals function as blowing agents, adhesion promoters, and activators or retarders which modify the onset of cross-linking. Organic chemicals which are used primarily in the rubber industry contributed $415 million to the United States economy in 1994. Other rubber chemicals are also discussed.