Systematic Investigations On Devulcanization of Used Rubber Materials By Means of Model Vulcanization

Concerning sustainability, economical aspects and the limited raw material resources effective devulcanization processes are the best choice for the recycling of used sulfur crosslinked rubber materials. A successful method is the treatment of vulcanizates by swelling in organic solvents in combination with reactive devulcanization agents. The objective is to generate rubber material from such a process, which can be vulcanized again without a decrease in physical properties. Existing methods are not very effective and could not be improved, because of a gap in knowledge about the chemical reactions in detail. One problem is, that polymeric matrices like vulcanized rubbers cannot be analysed in detail concerning the chemical reactions at crosslinks because of there insolubility. From this reason low molecular model vulcanizates are prepared on the base of dimethylbutene with systematic variation of crosslink density and of the crosslink structure (mono-, di- and polysulfidic bridges). The model vulcanizates were analysed before and after the treatment with different devulcanizing agents by means of GC-MS, HPLC, LC-MS. The methodology can be used for the improvement of the devulcanization process and to get fundamental information about the effectiveness of the used agents.