自製矽橡膠墊片在模擬質子交換膜燃料電池中之劣化實驗分析

Experimental Investigation and Analysis of the Degradation of Custom-made Silicone Rubber Gaskets in Simulated PEMFC Environment

吳旻貞(Min-Chen Wu)

指導教授 ： 張幼珍

元智大學/工程學院/化學工程與材料科學學系/碩士(2008年)

摘要

本研究是以市售液態矽橡膠自製矽橡膠墊片，在不同的質子交換膜燃料電池的物理與化學模擬環境下，以加速老化實驗與分析來探討溫度與時間對液態矽橡膠降解的影響，進而利用儀器分析結果推測可能的降解機制。結果包括TGA量測矽橡膠墊片在溶液浸泡前後，熱重損失隨溫度的變化；SEM觀察矽橡膠墊片在溶液浸泡前後，表面形貌上的變化，以及ATR-FTIR分析矽橡膠墊片在浸泡溶液前後官能基的變化。
實驗結果顯示矽橡膠在不同的模擬化學成分溶液浸泡下，熱重損失不同。SEM觀察到不同浸泡溶液造成不同的表面形態變化。譬如，過氧化氫會使矽橡膠表面脆化，進而發生龜裂，其它浸泡溶液則是使矽橡膠產生膨潤，接著析出矽橡膠內物質，嚴重時矽橡膠表面會有粗糙及破裂的狀況發生，接著破裂區域會繼續擴大。而在三種溶液同時浸泡下，硫酸對矽橡膠的影響則較為顯著，過氧化氫的影響則較不顯著。從TGA、SEM、ATR-FTIR的實驗結果可發現不同浸泡溶液對矽橡膠劣化影響很大，如1M硫酸會隨著溫度升高而加速矽橡膠的劣化，隨著浸泡時間增加，劣化狀況會愈趨嚴重。然而，並非所有溶液都有相同趨勢，從ATR-FTIR圖譜推測出降解過程中可能有-OH形成，但無法看出如文獻所提出的Si-O-Si的形成。此外，文獻中提出微量氫氟酸是破壞矽橡膠的主要因子，但本研究結果顯示1M硫酸似乎比為量氫氟酸的影響更大。

關鍵字

矽橡膠墊片、劣化、質子交換膜燃料電池、化學與物理模擬環境

並列摘要

The degradation of custom-made silicone rubber gaskets using commercially available liquid silicone rubber in simulated PEMFC environment was investigated analytically in accelerated aging experiments to reveal the effects of temperature and time. Analytical measurements were made to gain a better understanding of the degradation mechanisms of silicone rubber gaskets in PEMFC environment. The weight losses of test samples were measured as a function of time and exposure temperature in different chemical and physical environment. Scanning electron microscopy (SEM) was employed to examinee the morphological change on gasket surface before and after exposure to soaking solutions and mechanical stress. ATR-FTIR was used to analyze the change in functional groups of the samples before and after exposure to different environment.
The SEM results indicated that different morphologies were resulted for samples exposed to different environment. Cracks and their propagation with time were observed for samples soaked in hydrogen peroxide solutions. Overall, the aging experiments showed the samples subject to the various solutions were seriously wrecked over time. The results of weight losses, SEM, and ATR-FTIR showed temperature played a non-negligible role in the degradation, i.e. the higher the temperature, the faster the degradation of the samples.

並列關鍵字

silicone rubber gasket, PEMFC, simulated chemical and physical environment.

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