고압수소탱크 내고압수소용 고무소재 평가 및 개발에 관한 연구

Abstract

Recently, as a part of the development of new and renewable energy sources, the use of hydrogen, especially hydrogen fuel cell vehicles (FCV)and hydrogen stations, has been actively expanded. Various studies have been conducted on the behavior of structural materials in the production, storage, and transport of hydrogen under high-pressure hydrogen or liquid hydrogen environments. As the application field of hydrogen energy is expanding, development of technology for preventing accidents such as gas leakage and explosion due to damage caused by high pressure hydrogen environment of the materials is an urgent task. From this point of view, it is necessary to develop the rubber be capable of applying to the high pressure hydrogen and the evaluating the effect of hydrogen for rubber exposed with the high pressure hydrogen. In this study, the effects of high pressure hydrogen on rubber materials of three commonly NBR, EPDM, and FKM were evaluated by various techniques. The amount of hydrogen adsorption was measured by mass balance and the change of volume was measured by laser micrometer exposing the rubber materials to 35 MPa and 70 MPa high pressure hydrogen applied to hydrogen station and the hydrogen fuel cell vehicle. The hydrogen contents and volume of rubbers were increased with hydrogen exposure and hydrogen pressure increase. And then, hydrogen absorbed into the rubbers was evaporated and the volume was recovered with elapsed time. Tensile test was performed on the rubber material exposed to high-pressure hydrogen, and it was confirmed that the tensile strength was decreased with pressure increase and the tensile strength was recovered with elapsed time. And the durability of the rubber repeatedly with exposed the high pressure hydrogen was evaluated using the accelerated life test and stress relaxation. Rubber materials were repeatedly exposed to high pressure hydrogen 30 times and the exposed rubbers were heated from 100 and 150 degree for 14 days, respectively. The rubbers were severely influenced and the durability was reduced with exposed repeatedly with high pressure hydrogen. Finally the NBR, EPDM were produced with different filler kinds, content and crosslink system and the high pressure hydrogen effect was evaluated by tensile test. The tensile strength of NBR rubber with sulfur crosslink system was significantly decreased than those of EPDM with sulfur crosslink system in the high pressure hydrogen and the silica filler was better that carbon black filler in the high pressure hydrogen. In case of EPDM, peroxide crosslink system showed better properties than sulfur crosslink system in the high pressure hydrogen. From these results, we suggest that rubber materials applicable to the high pressure hydrogen are much better to employ a large of silica filler and peroxide crosslink system