On Friday, June 24th 2022, Mr. Hans van Hoek has successfully defended his PhD thesis entitled: “Closing the loop: Reuse of Devulcanized rubber in New Tires".
"Devulcanization is, with respect to recycling of rubbers, a promising technique. For passenger car tires, mainly consisting of blends of Styrene-Butadiene Rubber, Butadiene Rubber and Natural Rubber, a process on laboratory scale was developed by S.Saiwari in 2013. The present thesis describes the scaling up of the earlier developed lab process and transformation into a continuous process. In the next step, the influence of specific compounding additives and required process adjustments are elaborated. Last but not least, an application study for reuse of the devulcanizate in new passenger car tires is performed. Most important conclusion is that by separation of the silica containing tread compound from the remainder of the tire before shredding, the formulations and procedures for revulcanization can be tailored to the specific compounds. This results in better stress-strain properties compared to the revulcanized devulcanizate based on whole tire granulate. With these results, reusing the rubber of end-of-life tires for qualitative demanding applications is at hand."