Effect of Devulcanizer on the Properties of Natural Rubber Vulcanizates
Jin Kuk Kin and Marissa A. Paglicawan
Department of Polymer Science and Engineering Research Institute of Industrial Technology, Gyeongsang National University, Chinju Gyeongnam, Korea
The effect of De-Link R on the properties of natural rubber vulcanizates was investigated. Different amounts of De-Link R were added to the base formulation of natural rubber compound. The tensile properties were determined and correlated with the results of cure characteristics and crosslink density. Results showed that the maximum torque, scorch time, and cure time increase with increasing De-Link R content. However, the tensile strength and elongation at break drop tremendously as the amount of De-Link R content increases; whereas the modulus at 100% and 300% elongation increase due to the formation of new crosslink as indicated in the increase of crosslink density.
The three-dimensional network of the rubber can be prepared by the irreversible reaction of sulfur and rubber molicules. These crosslinked molecules create the useful viscoelastic properties of rubber compounds. The crosslinked rubber has good dynamic and physical properties. However, it is difficult to devulcanize the rubber compound and produce a useful material. Unlike thermoplastics where it can be reheater and remolded into a desired shape, rubber in crosslinked state cannot be softened or remolded by heating again. The three-dimensional network of the rubber must be broken down either through the cleavage of crosslinks, or through the carbon-carbon linkage of the chain backbone. This is an important mechanism in reclaiming or recycling of rubber compounds. Many studies . . . .
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