Canadian researchers demonstrated a gentle chemical method that can recover organic polymers from waste tire rubber. Their Lewis acid-catalyzed reductive silylation process can reduce the environmental impact of used sulfur crosslinked elastomers.
Carlos Scuracchio, who is engaged in rubber recycling at the Federal University of San Carlos, Brazil, said: “The recycling of vulcanized rubber is a major environmental problem, and its solutions have yet to be resolved.” High stability of vulcanized tire rubber Sex makes it difficult to recycle. Toxic ingredients may seep out of used tire stocks into the environment, and fires in such locations may be dangerous, very polluting and difficult to extinguish.
Michael Brook of McMaster University led the team in a new silylation process and had first-hand experience of tire fires. About 15 or 20 years ago, not far from where I lived in Hamilton, there was a very serious tire fire. The by-products are not good news for the local environment. ”
Now, Bruker’s research team has shown that hydrogen silane catalyzed by B(C6F5)3 can effectively reduce the sulfur-sulfur bonds in the complex sulfur-crosslinked tire rubber with a yield of up to 90%. They demonstrated their process on bicycle inner tubes, solid tires and tire scraps. The resulting polymerized, silyl-protected mercaptan oil can be separated directly by filtration or centrifugal separation. The research team also showed that they can make free radicals or oxidative cross-linking of the resulting oils to generate new elastomers, and build new toy tires on this basis.
In the presence of B(C6F5)3, the silylation reaction of reducing the RS-SR bond to silyl sulfide using various hydrogen silicon can be developed as a recycling process for automobile tires
To our surprise, you can actually dissolve and convert rubber into a liquid polymer material. I didn’t expect it to happen so well. He said, “There is very little literature on the depolymerization of vulcanized rubber” and “If there is a commercially feasible method, people will use it.” However, due to the need for 10wt% of “very expensive” catalyst to reduce the used tire rubber, Brook clarified, “In my opinion, there is no commercial method today. But I think this is thinking about how to degrade rubber to make it again. Useful polymers offer the possibility. The team is already optimizing the process to reduce the amount of catalyst required.
Scuracchio added: “Most rubber recycling technologies produce materials that are difficult to shape and process, and have completely different properties from the original raw materials.” “At this point, a very interesting part of the work is that rubber can be processed without having to Concerned about possible contamination, and the material produced is a rheologically simple oil that can be molded and transformed into a solid product. This factor makes this method very promising in the field of rubber recycling.”
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Post time: Oct-27-2020