English Abstract
Distribution of the Antioxidant Contained in the Vulcanized Rubber and the Rubber Degradation in Tap Water

Mio YAMADA1
Yoshihiko SUGIOKA1
Hiroto SHIN1
Yoshito OHTAKE2
1; INAX CO., LTD., Tokoname, Aichi, Japan
2; Chemicals Evaluation and Research Institute, Japan, Sugitomachi, Kitakatsushika-gun, Saitama, Japan
Nippon Gomu Kyokaishi,(2009),82(9),389-393 Original Paper in Japanese

Abstract
The relationship between distribution of antioxidant and degradation of polymer is investigated on EPDM compounded with IPPD that is a typical amine type antioxidant for vulcanized rubber. IPPD in EPDM homogeneously-dispersed by kneading is used. Because of decomposition by heat while molding and volatilization from surface of vulcanized rubber, more IPPD exists inside of rubber than the surface. At the depth of 0 ~ about 50m, percolation of water contained with residual chlorine and polymer degradation occur at the same time, IPPD disappears because of its dissolution into the water and consumption by trapping radical generated polymer degradation caused by residual chlorine and heat. In this area the rubber degradation occurs easily, so almost on the surface oxidation degradation progress even though antioxidant exists enough in vulcanized rubber.

(Received on February 10, 2009)
(Accepted on June 8, 2009)

Keywords:
Residual Chlorine, Degradation, EPDM, Antioxidant, IPPD, Dissolution, Blooming, Distribution
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