The effects of carbon blacks on vulcanization and mechanical properties of filled ethylene-propylene-diene rubber (EPDM) are investigated, by comparing with five types of rubber-grade carbon blacks. Curing kinetics is studied by rheometer and the results indicate that the curing characteristics are influenced by combination of surface area of carbon black and sulphur content on the filler surface, because the former one enhances the physical cross-linking and the latter one introduces the additional chemical cross-linking. Both the degree of cross-linking and cure rate increase with increasing surface area and sulphur content, whereas the optimum cure time and scorch time decrease. The reinforcing nature of the carbon black is assessed from mechanical measurements. It is suggested that the surface area of carbon blacks strongly affects the physical properties of EPDM/carbon black composites. Conductive carbon black (N472) can be used as desirable reinforcing filler due to the higher degree of cross-linking of EPDM with N472 than other EPDM/carbon black composites. The morphology and distribution of particles are studied by using scanning electron microscope. The sound reinforcing ability of N472 is also supported by scanning electron microscope due to the notable dispersibility of N472 within EPDM matrix. N472 ensures the EPDM/N472 composite the most conductive sample among the five composites

The aim of this article is to study the effect of antioxidants on cure properties and aging behaviour of ethylene propylene diene rubber (EPDM) and EPDM/low density polyethylene (LDPE) blends. Dicumyl peroxide cured EPDM and EPDM/LDPE blends are prepared with three categories of antioxidants, including: amine, N-isopropyl-N9-phenyl-r-phenylenedia mine (antioxidant 4010NA) and 2,2,4-trimethyl-1,2-dihydroquinoline (antioxidant RD); phenol, n-Otadecyl-b-(4-hydroxy-3,5ditert-butyl-phenyl)-propionate (antioxidant 1076) and sulphur containing antioxidant, 2mercapto benzimidazole (antioxidant MB). The damp heat aging was carried out at a relative humidity of 93% and a temperature of 40uC. The thermal aging was performed at 120uC. The two types of aging have been taken for eight weeks respectively. The combined antioxidant RD/MB is a favourable additive. The cure characteristics of EPDM with antioxidant RD/MB are notable compared with those of EPDM without antioxidants. Additionally, antioxidant RD/MB has the sound aging performance for the EPDM and EPDM/LDPE blend. Antioxidant 4010NA performs poorer than others during aging, due to the remarkable retardation for the peroxide vulcanisation process.