Development of a Rubber Recycling Process Based on a Single-Component Interfacial Adhesive

A simple and cost-effective adhesive-based rubber recycling process was designed as an alternative to devulcanization. Interfacial bonding between vulcanized and virgin rubbers is improved by incorporating adhesives and coating processes during rubber reblending and reducing interfacial defects that cause premature failure. In flat laminates, the bond strength between vulcanized and virgin materials doubles when a vulcanizing fluid and thin adhesive layer are introduced. These components are combined into single-component adhesives (SCAs), which improve bond strength sixfold over no treatment, using half the raw material as the multilayer adhesive. When SCAs are coated onto vulcanized rubber particles prior to reblending, the best rubbers exhibit nearly 50% increases in mechanical strength and toughness vs the untreated control and statistically identical extensibility; all treatments improved mechanical strength. This simple, inexpensive, and scalable process can be implemented with one step beyond standard reblending and curing, providing a promising alternative to devulcanization for polymer recycling.