| 학회 | 한국고분자학회 |
| 학술대회 | 2004년 가을 (10/08 ~ 10/09, 경북대학교) |
| 권호 | 29권 2호, p.517 |
| 발표분야 | 고분자 구조 및 물성 |
| 제목 | Synthesis of Sulfonated Polyimide for High Temperature polymer electrolyte membrane |
| 초록 | Among the various kinds of fuel cells, due to the simplicity in operation, PEMFC are the forerunner in the field. The electrolyte is the most important component of any fuel cell system. Various Ionic membranes were extensively studied to serve as fuel cell electrolytes and Nafion is the most well studied membrane of them. But there are few drawbacks associated with the perfluro sulfonic acid membranes namely (1) the high cost make this product economically unviable for common applications (2) the rapid loss of ionic conductivity at high temperature and low humidity. These drawbacks triggered an extensive research to develop alternative PEM material for PEMFC. Polyimides possess many salient features to be used in PEMFC, still, the main drawback associated with polyimides are their hydrolytic stability, which is very sensitive to their chemical structure. The flexible systems are reported to exhibit more hydrolytic stability and moreover the Tg of these polymers will be low favoring easy migration of the protons. Also it has been reported that free volume in the non-sulfonated phase contribute to increased conductivity at elevated temperature. In this study a series of six-membered polyimides were synthesized by altering the non-sulfonated diamine monomers having different bridging groups, and the synthetic route. These diamine monomers are selected on the basis of increasing bulkiness of the bridging atom and their effect on properties are studied in detail. All the polyimides exhibited characteristic high thermal stability. The IEC and water uptake reduced with increase in the bulkiness of the bridging group The hydrolytic stability of the polyimides with bulky bridging group is higher than the polyimides with less bulky atoms due to the imparted flexibility. All the polyimides exhibited lower conductivity than Nafion115 at low temperatures and comparable conductivity at temperatures above 50oC. The increase in conducvity with temperature is more rapid in the case of polyimides than in Nafion115. The polyimides with bulky bridging groups showed pronounced conductivity at high temperature than the MDA and Nafion115. This is due to the increase in the free volume in the non sulfonated polyimide segment which increases the proton conductivity at high temperature due to the possibility of easy migration of water molecules This work was supported by the Ministry of Science and Technology of Korea through the National Research Laboratory Program |
| 저자 | 장원봉, 이춘근, 권진욱, S. Sundar, 설용건, 한학수 |
| 소속 | 연세대 |
| 키워드 | sulfonated polyimide |
