Rubber plasticizers from degraded/devulcanized scrap rubber: A method of recycling waste rubber

Seeking a solution to the problem of disposing scrap tires, we attempted to depolymerize or degrade vulcanized rubber scrap such that the resulting pseudo-liquid material could be used as an extender/plasticizer in virgin rubber compounds. As degraded natural rubber (DNR) and degraded styrene-butadiene rubber (DSBR) are polymeric in nature (confirmed from gel-permeation chromatography (GPC) and differential scanning calorimetry (DSC) results), they can be unique substitutes for typical rubber plasticizers (oil). DNR-loaded samples have shown better mechanical property retention after aging and a lower extractable content in acetone than the respective oil-plasticized samples. Solvent swelling in toluene and 100% modulus values indicate that DNR-added rubber vulcanizates undergo a phase adhesion between the rubber matrix and the degraded polymer, as well as incurring extra reinforcement due to particulate carbon black present in the degraded rubber. Polym. Eng. Sci. 44:1338–1350, 2004. © 2004 Society of Plastics Engineers.

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