水道水残留塩素に侵されるEPDMパッキンの劣化メカニズム The Degradation Mechanism of EPDM Packing by Chlorine in City Water
In order to elucidate the degradation mechanism of EPDM rubber caused by a amount of chlorine in city water, EPDM rubbers containing 2 kinds of carbon black (ie. HAF and FT) were employed and corroded in chlorine water, Their morphology changes before and after degradation were observed by SEM. The effect of the amount of moisture Was examined by EPMA. The degradation mechanism was studied by XPS and <sup>13</sup>C-NMR. The EPDM rubber loaded HAF was easier to absorb chlorine and to be deteriorated than the one loaded FT. As a result of XPS measurement, Cl (2p) peak was detected from the sample after degradation treatment. <sup>13</sup>C-NMR measurement revealed that the methyl group of diene side chain of EPDM rubber was changed into the chlorinated methyl group. It was thought that as the chlorinated methyl group reacted with the other molecular chains of EPDM rubber, the crosslinking density increased. Therefore, the degraded EPDM rubber was brittle, collapsed and fell off.
日本ゴム協會誌 75(7), 313-317, 2002-07-15
THE SOCIRETY OF RUBBER SCIENCE AND TECHNOLOGYY, JAPAN