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Unformatted text preview: m S CH 2-CH 2-CH-CH 2 CH-CH=CH-CH 2 CH 2-CH=CH-CH 2 (sulfonium ion) reacts with a polymer by hydride abstraction + m S CH 2-CH CH-CH 2 heat-+ n m S S S 8 CH 2-CH=CH-CH 2 Vulcanization of a diene containing polymer by heating with sulfur alone is a very inefficient process, wasted by the formation of long polysulfide crosslinks. Commercial sulfur vulcanization are carried out in the presence of various additives (accelerators and activators), including organo-sulfur compounds, zinc oxide and fatty acid which greatly increase the rate and efficiency of the process. Due to the low diene concentration in both butyl and EP rubbers, the halogenated polymers conctaining allylic halide significantly improve the crosslinking reactivity. Brominated butyl rubber shows higher vulcanization rates than chlorinated and normal butyl rubber....
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This note was uploaded on 10/16/2010 for the course MATSE 441 taught by Professor Chung,tze-chiang during the Fall '10 term at Pennsylvania State University, University Park.
- Fall '10