Reprocessing of injection-molded magnetorheological elastomers based on TPE matrix

Abstract

Nowadays, the magnetorheological elastomers (MREs) represent an important composite group with a wide range of applications. They are however predominantly typified by chemically cross-linked polymer matrices which makes them difficult to be reprocessed or recycled. Here, we demonstrate the concept of the MREs’ reprocessing for the first time. The thermoplastic elastomer (TPE) was adopted as a suitable matrix allowing the MRE production via injection-molding, while making them also reusable. Each processing iteration was accompanied by thermo-mechanical degradation causing the gradual TPE oxidation, decrease in the TPE molecular weight and a viscosity reduction of their melts. In the MREs, the unexpected processing-induced particle/matrix bonding was revealed, which promoted their stiffening. As a result, the magnetic field-induced particle mobility was limited decreasing the magnetorheological activity of the MREs by tens of percent per the processing cycle. We expect that the injection-molded TPE-based MREs could offer a new pathway for producing the smart engineering composites owing to the ability to be easily reprocessed.