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.

Casted PVC films with hindered amine light stabilizer (HALS) and antioxidants are photo-irradiated for 400 h and the process of photodegradation is characterized by color differences, ultraviolet-visible (UV-vis) spectroscopy, Fourier transformation infrared (FT-IR) spectroscopy and viscosity-average molecular weight (M ). When added to PVC separately, hindered amine derivate (T770) and phenol antioxidant ( 1076) both have little effect on the dehydrochlorination and oxidation of PVC films. In PVC films with T770/1076, the extension of shorter polyenes is retarded during photo-irradiation of 400 h. The extension of longer polyenes is well retarded from 0 h to 200 h. T770/ 1076 has only a little effect on the anti-oxidation of PVC films from 0 h to 400 h. The p-phenylenediamine antioxidant (4010NA) and 2-Mercapto benzimidazole (MB) both accelerate the photodegradation and crosslinking of PVC films. However, there is no crosslinking in PVC with T770/4010NA and PVC with T770/MB and the degradation of PVC films is weakened. This phenomenon means the light stabilizer T770 protects antioxidants (4010NA and MB) from photo-irradiation and antioxidants can play a positive role in the antioxidative effect.

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