Technical Notebook: Carbonized soybean hull as a sustainable filler in rubber products

Many rubber manufacturers are looking for sustainable alternatives to synthetic filler products derived from fossil fuels.

Carbon black owns the lion’s share of the filler market but is plagued by costs that are indexed to the price of oil, EPA regulations and the status as a carcinogen. Unfortunately, most mineral fillers have inferior properties, are hard to process and have higher specific gravities that increase the weight of the end rubber product.

Soybean hull has the potential to be a cost-effective and sustainable alternative filler that does not impact the food supply. This paper evaluates the ability of soybean hull to be ground, carbonized in a nitrogen atmosphere and used as a partial replacement for carbon black.