Thermoplastic dynamic vulcanisates containing LDPE, rubber, and thermochemically reclaimed ground tyre rubber

Thermochemically devulcanised ground lyre rubber (GTR(DL)) was added to fresh rubber compositions, which were then melt blended,kith low density polyethylene (LDPE). Styrene butadiene rubber (SBR), natural (NR), an ethylene propylene, diene (EPDM) rubbers were selected as the fresh rubbers, During blending. dynamic curing was achieved using sulphuric, phenolic, and peroxide curing agents. Some of the GTR was decomposed in the presence of 6 phr Regen(TM) Agent-S reclaiming compound before being incorporated into the blends. The resulting thermoplastic dynamic vulcanisates had constant compositions, namely LDPE rubber GTR = 50: 25: 25. Sulphuric and phenolic curing agents proved to be most Suitable for dynamic curing. The thermoplastic dynamic vulcanisates with the best mechanical performance contained SBR and EPDM rubbers. The observed improvements in mechanical performance were attributed to chain entanglement and co-crosslinking in the interphase between the GTR(DL) particles and the surrounding matrix (i.e. with the fresh rubber and or LDPE). The phase morphology. which was assessed using scanning electron microscopy on the etched surfaces of cryogenically fractured thermoplastic dynamic vulcanisate compositions. is discussed. (C) 2002 IoM Communications Ltd.