Study Shows Lehigh Rubber Powder ‘Adds Value’ to Tyres

Engineered rubber powder manufacturer Lehigh Technologies, Inc., has announced the results of studies that show its flagship product, PolyDyne rubber powder, can be used as a chemically functioning element in the manufacture of new tyres. This takes the use of rubber powder in tyres beyond its existing role as a mere static filler and enables the product to add value to the finished tyre.

The research was carried out by the Department of Chemistry at South Carolina’s Clemson University. “There has been some question in terms of the extended use of ultra-fine rubber powder and its realistic functionality in new products,” said Dennis W. Smith, Professor of Chemistry at Clemson University. “Our study illustrates that used tyre rubber powder prepared by the Lehigh process is in fact unique and does offer a value-added reactivity and functionalisation. Breakthrough results from electron paramagnetic resonance spectroscopy (EPR) measurements indicate that the Lehigh process provides a significant increase in free radicals, which can bond to matrix resins or other application-specific substrates, extending the powder’s usefulness beyond that of an added filler. With this study, tyre manufacturers worldwide have a viable alternative ingredient that can be used to make ‘green’ tyres, while at the same time enhancing the performance of the tyre. We’re confident that tire manufacturers will see the environmental and economical benefits that PolyDyne powder brings to the table.”

Lehigh’s patent-pending process for mechanical shearing and grinding of used tyre rubber uses a cryogenic aided, turbo-shearing mill to produce rubber powder of controlled particle size and size distribution. In this process, a mechano-chemical effect is created, whereby primary covalent bonds (C-C, C-H and C-O) and secondary van der Waals or hydrogen bonds are ruptured, leading to partial devulcanisation and the creation of free radical receptor sites on the surface of the vulcanisate rubber powder. These functional rubber compounds enable an increase in sulphur content, leading to greater cross-link density, resulting in improved tensile strength. The rubber powders obtained by this process can be incorporated into various polymer and rubber matrices with improved mechanical, physical and processing characteristics.