不同交聯度PNIPAAm感溫性水膠之機械及膨潤收縮性質探討

A Study on the Mechanical and Swelling Shrinking Properties of Different Cross-linking Poly N-isopropylacrylamide Hydrogels

范國毅(Guo-Yi Fan)

指導教授 ： 魏哲弘

大同大學/工程學院/機械工程學系所/碩士(2012年)

摘要

本論文探討含不同濃度的PNIPAAm溫度應答型水膠，對於機械性質和膨潤收縮性質的影響。PNIPAAm水膠會受高溫影響收縮，受低溫影響膨潤，而影響膨潤收縮行為的相變化溫度(LCST)為32℃。首先將水膠放置在25℃水中以及40℃水，並觀察各濃度水膠膨潤收縮程度。並且將不同配方的水膠以微米壓痕機器改變加載速率以及最大負載測量乾燥狀態下PNIPAAm水膠的硬度以及楊氏係數。膨潤收縮實驗得知水膠濃度中單體越高，膨潤收縮效果有越高的趨勢。若單體比例越低結果則反之。而水膠濃度中交聯劑比例高膨潤收縮效果差。所測得的硬度及楊氏係數的變化，發現在加載速率越低時，水膠的硬度和楊氏係數會提高，而在最大負載越大時，水膠的硬度和楊氏係數則是顯示上升的趨勢。使用電子式掃描顯微鏡(SEM)觀察經過冷凍乾燥水膠在不同濃度下孔洞結構的情形。觀測的結果看出在交聯劑以及單體濃度提高的情形下，孔洞結構較為緻密，間接證實微米壓痕實驗結果。

關鍵字

楊氏係數 ； 水膠 ； 膨潤收縮 ； 壓痕 ； 硬度

並列摘要

This thesis studies on the mechanical and swelling shrinking properties of different cross-linking of thermo-sensitive hydrogel. Thermo-sensitive poly N-isopropylacrylamide Hydrogel has the property of swelling when cold and shrinking when hot. The Lower critical solution temperature(LCST) of poly N-isopropylacrylamide Hydrogel is about 32℃. This study first use swelling shrinking experiments in 25℃ and 40℃ to find volume swelling and shrinking ratio. For higher cross-linking hydrogel, the swelling ratio and shrinking ratio are greater than those of lower cross-linking. This study can use the indentation experiment to find the mechanical properties, too. The mechanical properties elastic modulus and hardness of dry hydrogel are investigated via indentation experiment. These properties are dependent on the loading rate as well as the peak load due to the viscoelastic nature. For lower loading rate, the hardness and elastic modulus of dry hydrogel are greater than those of higher loading rate. For higher cross-linking, the hardness and elastic modulus of dry hydrogel are greater than those of lower cross-linking. The different cross-linking freeze-dried hydrogel are examined via SEM. By SEM we can know if hydrogel has porous structure more, the hardness and elastic modulus are better.

並列關鍵字

Swelling Shrinking ； Indentation ； Hardness ； Hydrogel ； Elastic modulus

參考文獻

討，大同大學機械工程學系。

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