Thermoreversibly crosslinked silica-rubber composite prepared via melt processing

This paper addresses the industrially viable and environmentally sustainable preparation of thermoreversibly crosslinked composite rubbers. A maleimide-functionalized silica (Sil-M) is prepared and used as a reinforcement filler and crosslinking agent via Diels-Alders (DA) reaction onto furan-grafted ethylene-propylene rubber (EPRgF). The preparation of composite rubbers is carried out by reactive melt blending to guarantee for industrial scalability and avoiding use of organic solvent. Mechanical properties of EPRgF/Sil-M is compared to unfunctionalized EPRgF/Sil to demonstrate the role of DA crosslinking on mechanical properties. Furthermore, the combination between Sil-M and bismaleimide as a conventional DA crosslinker was investigated, to optimize crosslinking degree and materials performances. Overall, results reported in this paper demonstrate the possibility to develop a new class of recyclable composite rubbers for the substitution of conventional rubbers, that are currently causing major problems in the management of rubber products at their end-of life.