Mechanochemical devulcanization of butadiene rubber with DPDS as a devulcanization aid

Millions of used tires are generated each year. In order to reduce this incredible amount of post consumer waste, legislations are introduced. ese also address the tire industry, where more recycled rubber has to be used. However, the devulcanization of rubber remains a challenge. Polybutadiene rubber (BR) is one type of rubber used in tire production. Due to its specific chemical structure, BR has been reported to be difficult to recycle; in reclamation or devulcanization. In this study, several conditions were tested for the devulcanization of BR with the use of DPDS in order to elaborate the best conditions for an efficient process. The results are described in terms of soluble fraction, cross link density and displayed in a Horikx plot. e addition of DPDS leads to effective devulcanization: the sol fraction increases and the crosslink density decreases. When the devulcanization temperature is higher than 200 °C, the degree of devulcanization decreases. At 250 °C dumping of the devulcanizate immediately after devulcanization in liquid nitrogen is necessary to avoid oxidative degradation of the devulcanizates. Prolonging the devulcanization time reduces the degree of devulcanization, which implies recombination of the broken crosslinks.