Oven Ageing versus UV Ageing Properties of Natural Rubber Cup Lump/EPDM Rubber Blend with Mangosteen Powder (MPP) as Natural Antioxidant

Abstract

Natural Rubber (NR) are susceptible to oxidation due to the presence of diene double bond. Improvement of NR properties can be enhanced by presence of antioxidant. Natural antioxidant can be a new source of additives to prevent and delay oxidation process. In this work, mangosteen powder (MPP) is exploited to be good potential additive in improving the aging properties of NR cup lump (NRCL) blended with EPDM rubber. Blended NRCL with EPDM rubber as a sealant had been studied with and without MPP. Aging effects upon thermal and weather exposure after two weeks had been analyzed by FTIR. Increasing amount of MPP had retained the diene bonds upon further rubber degradation. The broad band absorbance peak at 3410 cm−1 corresponds to O-H stretching with H-bond which indicates the existence of phenols in the MPP. Carboxylate groups and amine presence in MPP also found to exhibit absorbance peak at 1028 and 1608 cm−1 respectively. MPP contained polyphenol proven to be effective antioxidant agent in reducing degradation upon thermal and sunlight exposure. Oven and weathering tests performed for two weeks showed different aging behavior with weathering exposure found to have greater degradation effect due to radical attack by free radical from UV sunlight.