Devulcanization Process Technologies

Several devulcanization process technologies were invented by Lee and his graduate students. These technologies include:

(1) recycling of waste rubber products such as spent tires in forms of monomeric materials such as isoprene, which can be used as raw materials for polymerization
(2) recycling spent tire rubber via devulcanization into re-vulcanizable rubber
(3) processing spent tire with other fuel sources such as biomass or coal, for power generation as well as for generation of liquid transportation fuels.

The first technology was developed with research funding from BF Goodrich Co., whereas the second was developed in collaboration with scientists and engineers of Goodyear Tire & Rubber Co. U.S. patents awarded for these technologies are:

S. Lee and F. O. Azzam, "Oxidative Decoupling of Scrap Rubber", U.S. Patent 5,516,952 , May 14, 1996 .

D. Benko, R. Beer, S. Lee, and K. Clark, “Devulcanization of Cured Rubber”, U. S. Patent 6,992,116 , January 31, 2006.

There are a number of international patents also awarded for the above processes. Some of the revolutionary ideas for C-S bond cleavage reactions were very well demonstrated in Lee’s earlier patent in coal desulfurization process. This patent not only teaches how to induce selective cleavage reactions on the coal C-S bonds, such as the ones in dibenzothiophenes, but also shows the synergistic use of a binary or ternary supercritical fluid system as an effective supercritical solvent/reactant. The impact of this research result is very significant in widely diverse fields of applications, outside of the coal desulfurization area, including biofuel processing, pharmaceutical processing, and extraction of biologically active ingredients from plants.

S. Lee and V. Parameswaran, "Selective Extraction Process of Sulfur from U.S. Coals Using Supercritical Fluids", U.S. Patent 5,080,692 , January 14, 1992 .

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