質子交換膜燃料電池組需要墊片密封，以便氫氣及空氣/氧氣能維持於其相對空間內，故墊片的穩定性質對燃料電池的使用壽命及電化學效能是很有影響的。本文將五種墊片材料分別置入模擬之電池使用環境溶液與加速測試溶液中於電池操作溫度下浸泡六十三週，以觀察其化學破壞效果。這五種材料分別是樹脂膠(Copolymeric Resin, CR)、矽膠(Liquid Silicone Rubber, LSR)、氟矽膠(Fluorosilicone Rubber, FSR)、 乙丙橡膠(Ethylene Propylene Diene Monomer Rubber, EPDM)及氟橡膠(Fluoroelastomer Copolymer , FKM)。本研究採用化學降解程度之觀察，動態機械分析及微壓痕測試等三種方式來評估材料之耐久性。
實驗結果顯示，化學浸泡的溶液將會對試片表面以及機械性質造成影響，並且會隨者浸泡時間有所不同。
若以材料化學降解與機械性質為主要考量，EPDM應為用於質子交換膜燃料電池墊片材料之最佳選擇。

Proton Exchange Membrane (PEM) fuel cell stack requires gaskets and seals in each cell to keep the hydrogen and air/oxygen within their respective regions. The stability of the gaskets is critical to the operating life as well as the electrochemical performance of the fuel cell. Chemical degradation of five elastomeric gasket materials in a simulated and an aggressive accelerated fuel cell solution at PEM operating temperature for up to 63 weeks was investigated in this work. The five materials are Copolymeric Resin (CR), Liquid Silicone Rubber (LSR), Fluorosilicone Rubber (FSR), Ethylene Propylene Diene Monomer Rubber (EPDM), and Fluoroelastomer Copolymer (FKM). In order to assess the durability of the materials, observation of chemical degradation level, dynamic mechanical analysis, and micro-indentation test were adopted in this study.
This experimental result showed that the influence of the chemical reaction could affect the material surface condition. Also, the chemical reaction could affect material’s mechanical properties had been changed over the soaking time.
By considering the level of chemical degradation and mechanical properties, the experimental results showed that EPDM is recommended as the best choice of sealing material for using in a PEMFC.

摘要 ……………………………………………………………………………………………………………………………………… i
Abstract ………………………………………………………………………………………………………………………………… ii
Contents …………………………………………………………………………………………………………………………………iii
List of Figures ……………………………………………………………………………………………………………………… vii
List of Tables ……………………………………………………………………………………………………………………..… xiv
Nomenclature ………………………………………………………………………………………………………………………..… xvi

Chapter 1 Introduction …………………………………………………………………………………………………………………1
1.1 Background …………………………………………………………………………………………………………………………1
1.2 Review of Literatures ………………………………………………………………………………………………………… 2
1.2.1 Chemical Degradation Level …………………………………………………………………………………………………2
1.2.2 Dynamic Mechanical Analysis ……………………………………………………………………………………………… 4
1.2.3 Micro-indentation …………………………………………………………………………………………………………… 5
1.3 Research Motivation and Purpose …………………………………………………………………………………………… 6
1.4 Structures of the Dissertation ………………………………………………………………………………………………7

Chapter 2 Experimental Method and Analysis ………………………………………………………………………………………9
2.1 Materials and Simulated PEM Fuel Cell Environments ……………………………………………………………………9
2.2 Chemical Characterization Method ……………………………………………………………………………………… 11
2.3 Dynamic Mechanical Analysis ………………………………………………………………………………………………12
2.4 Micro-indentation Experimental Method …………………………………………………………………………………14
2.4.1 The Loading Curves ………………………………………………………………………………………………………… 14
2.4.2 Hertz Contact Model …………………………………………………………………………………………………………15
2.4.3 The Loading-unloading Behavior and Loss Energy Method…………………………………………………………… 16
2.4.4 Hardness Experimental Method …………………………………………………………………………………………… 16

Chapter 3 Chemical Degradation Level …………………………………………………………………………………………… 21
3.1 Surface Observation …………………………………………………………………………………………………………21
3.2 Weight Loss ……………………………………………………………………………………………………………………21
3.3 Optical Microscopy ………………………………………………………………………………………………………… 22
3.4 Atomic Absorption Spectrometry ………………………………………………………………………………………… 24
3.5 Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) Analysis ……………………………… 26
3.5.1 Copolymeric Resin (CR) …………………………………………………………………………………………………… 26
3.5.2 Fluorosilicone Rubber (FSR) ………………………………………………………………………………………………27
3.5.3 Liquid Silicone Rubber (LSR) …………………………………………………………………………………………… 28
3.5.4 Ethylene Propylene Diene Monomer Rubber (EPDM) …………………………………………………………………… 29
3.5.5 Fluoroelastomer Copolymer (FKM) …………………………………………………………………………………………30
3.6 Results and Discussions ……………………………………………………………………………………………………31

Chapter 4 Dynamic Mechanical Characteristics ………………………………………………………………………………… 51
4.1 Material Properties from DMA………………………………………………………………………………………………51
4.1.1 Copolymeric Resin (CR) …………………………………………………………………………………………………… 51
4.1.2 Fluorosilicone Rubber (FSR) ………………………………………………………………………………………………52
4.1.3 Liquid silicone Rubber (LSR) …………………………………………………………………………………………… 52
4.1.4 Ethylene Propylene Diene Monomer Rubber (EPDM) …………………………………………………………………… 53
4.1.5 Fluoroelastomer Copolymer (FKM) …………………………………………………………………………………………53
4.2 Effects of Aging on the Storage Modulus and Tan δ of the Materials …………………………………………54
4.3 DMA Properties of the Five Materials Relevant to Sealing in PEM Fuel Cells ……………………………… 55
4.4 Results and Discussions ……………………………………………………………………………………………………56

Chapter 5 Micro-indentation Experimental Analysis ……………………………………………………………………………74
5.1 The Loading Curves ………………………………………………………………………………………………………… 74
5.1.1 Copolymeric Resin (CR) …………………………………………………………………………………………………… 74
5.1.2 Fluorosilicone Rubber (FSR) ………………………………………………………………………………………………75
5.1.3 Liquid Silicone Rubber (LSR) …………………………………………………………………………………………… 77
5.1.4 Ethylene Propylene Diene Monomer Rubber (EPDM) …………………………………………………………………… 78
5.1.5 Fluoroelastomer Copolymer (FKM) …………………………………………………………………………………………79
5.2 Hertz Method Fit …………………………………………………………………………………………………………… 81
5.3 Elastic Modulus ………………………………………………………………………………………………………………81
5.4 Loss Energy (Hysteresis) and Hardness Behavior …………………………………………………………………… 83
5.4.1 Copolymeric Resin (CR) …………………………………………………………………………………………………… 83
5.4.2 Fluorosilicone Rubber (FSR) ………………………………………………………………………………………………84
5.4.3 Liquid Silicone Rubber (LSR) …………………………………………………………………………………………… 85
5.4.4 Ethylene Propylene Diene Monomer Rubber (EPDM) …………………………………………………………………… 86
5.4.5 Fluoroelastomer Copolymer (FKM) …………………………………………………………………………………………87
5.5 Compared with the Five Materials ……………………………………………………………………………………… 88
5.6 Results and Discussions ……………………………………………………………………………………………………91

Chapter 6 Conclusions and Future Prospects ……………………………………………………………………………………118
6.1 Conclusions ………………………………………………………………………………………………………………… 118
6.2 Future Prospects ……………………………………………………………………………………………………………120

References ………………………………………………………………………………………………………………………………123
VITA ………………………………………………………………………………………………………………………………………132

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