You will be speaking about Source-dependent variability of recovered carbon black from end-of-life-tyres and its influence on EPDM rubber performance. Can you share some details about your presentation?
My presentation mainly focuses on how the different source and replacement level of recovered carbon black affect the performance of an EPDM-based compound. For this aim, we tested rCB sources from 3 different countries, with a different replacement levels, from 25 to 100%. We compared them with a conventional furnace carbon black.
For comparison, we investigated processing behaviour, cure characteristics, mechanical properties, and thermal aging. We also used statistical methods such as two-way ANOVA, principal component analysis (PCA), heatmap and hierarchical clustering to understand the overall performance and finding the best option. Our target is to identify the best balance between sustainability, processability, and product performance.
Variability and consistency are frequently discussed as barriers to wider rCB adoption. How significant are the differences between rCB materials from different feedstocks and suppliers?
As the replacement level increases, the difference can be more noticeable. both the replacement level and the rCB source had a significant effect on processing, curing, and mechanical properties. We also found that magnitude and direction of the changes were not identical for each source.
At lower replacement levels, especially up to 25%, the performance was closer to the reference compound. One of the sources also showed a relatively balanced performance profile at 50% replacement. I called this an “optimization candidate”. This means higher substitution levels may be possible with some formulation optimization. This shows that rCB should not be treated as a single, uniform material. When choosing a supplier, we should look at the overall performance of each source, not just the replacement level.
You mention that ash content and surface activity are key drivers of performance. Why are these characteristics so critical?
Ash content is important because rCB is a pyrolysis product of waste tires. During the pyrolysis most of the organics can be decomposed but it still contains inorganic materials that we called “ash content” and do not simply disappear during the process. This is also related to what we called the “memory” of their originating in our previous rCB study. The rCB can carry some characteristics from its previous life in the tire, and these characteristics can still influence the performance of the new compound. In other words, a higher ash content can change how the rCB interacts with the rubber and how efficiently reinforce the compound.
Finally, what are you most looking forward to about joining the rCB community at the conference this year?
Sharing our practical experience with rCB producers, researchers, and industrial users. I also like to show how statistical tools can help us compare different rCB sources and make the selection process faster and more reliable.
For me, this conference is a great opportunity to connect our laboratory results with real industrial challenges and hopefully find new opportunities for collaboration.
