臺灣國際科展

奈米複合材料與空氣分子的愛恨情仇-探討奈米碳管對空氣滲透率之影響

科展類別
臺灣國際科展
屆次
2008年
科別
環境科學
得獎情形
第二名
學校名稱
國立臺中女子高級中學
指導老師
陳鴻仁
作者
蔡佩芩
關鍵字
醚亞醯胺溶液 玻璃態高分子

摘要或動機

本實驗使用聚醚亞醯胺溶液製備基本薄膜,由於玻璃態高分子薄膜過於緻密,一直是高分子薄膜在應用上的一大限制,為了在薄膜上製造缺陷,又不會使薄膜之選擇性降低,因此選擇將酸化之奈米碳管(孔徑10~20nm) 加至聚醚亞醯胺薄膜中。本實驗主要為探討添加不同濃度的酸化奈米碳管對聚醚亞醯胺薄膜的滲透率與選擇率的影響,藉由添加0.5 wt%、1 wt%、1.5 wt%、3 wt%、4 wt%等不同濃度的酸化奈米碳管至15 wt% 的聚醚亞醯胺溶液中,並製作薄膜,測試其基本性質與五種氣體(H2、CO2、O2、N2、CH4)的滲透率及不同空氣分子之間的選擇率。我們總共測試了三種薄膜的性質,分別是表面特性、熱穩定性及結晶型與層間距,薄膜的表面性質,能觀察到奈米碳管在薄膜中製造奈米孔隙結構,增加氣體滲透的孔道,能有效增加氣體的滲透率。增加奈米碳管的量,能有效升高第一階段熱裂解的溫度,雖然熱裂解在本實驗中沒有很大的差異,但是還是可以從熱重分析圖中推測不同量的奈米碳管會影響熱穩定性。在X 光繞射實驗中,添加奈米碳管的薄膜與純聚醚亞醯胺薄膜,在結晶相上都屬非結晶型薄膜,添加了奈米碳管的高分子複合薄膜的層間距明顯增大。在氣體滲透實驗中,我們比較了不同氣體或濃度不同的奈米複合薄膜的氣體滲透率,在不同氣體時,氣體的滲透率會隨著奈米碳管濃度增加有明顯的提升,五種氣體滲透率大致依照H2>CO2>O2>N2>CH4 這個趨勢增減。奈米碳管對1.5%增加到3%或4%的奈米複合薄膜滲透率的影響卻減小,由此可以推斷奈米碳管對空氣滲透率並非無限制的增加,在1.5%以後就漸漸趨近最大值。H2為14.89barrer,CO2 為9.51barrer,O2為6.34barrer,N2為6.48barrer, CH4 為3.75barrer 。本研究總共比較了三組氣體的選擇率,分別是CO2/CH4,O2/N2,H2/CH4,分離率最高的是H2/CH4 的,兩分子的粒徑大小差對分離率有極大影響,差愈大,其分離率也愈高。奈米碳管的量改變並不會使薄膜的氣體選擇率明顯增加或減少,但是加入太多奈米碳管其選擇率會變低。在五片薄膜中,1.5%的薄膜有最好的選擇率,奈米碳管的添加量超過1.5%選擇率就會開始下降。綜合滲透率及選擇率可以分析出,添加1.5%奈米碳管的高分子奈米複合薄膜有較高的滲透率,又不會降低選擇率,在利用上比其他濃度的奈米複合薄膜在有害氣體過濾及空氣的分離回收方面產生更好的效果。;This experiment uses Polyetherimide polymers solution to make basic membranes. Because glassy polymer membranes are too dense for gas permeations, it is one of the limitations in their applications. To increase gas permeability and maintain air selectivity, I made some nanogaps on the surface of the membranes by an acidification multi-wall carbon nanotubes (MWNTs, kinetic diameter 10~20nm) in the PEI membranes. We mainly want to find if it has some influence between the consistency of acidification MWNTs and gas permeability or selectivity. We mixed 0.5wt% 、1wt%、1.5wt%、3wt%、4wt% acidification Carbon nanotube in 15wt% PEI solution, made membranes and tested the character, five kinds of gas permeability (H2、CO2、O2、N2、CH4) and the selectivity between different gases. We have tested the three nature of membranes, including surface characteristic, TGA and XRD. We can see some nanogapes made by carbon nanotube in the membranes. It could availably increase gas permeability. Mixing more carbon nanotube in the membranes could increase the temperature of the first heat-decomposition. Though the heat-decomposition in this experiment didn’t change a lot, we could say that different percent nanotube would affect the membranes’ heat-decomposition. By the experiment of XRD, the membranes with carbon nanotube and the pure PEI membranes attach to amorphous membranes. Nanocomposite’s de-spacing is bigger than pure membranes. In the experiment of air permeability, we compared different kinds of gas or different percent carbon nanotube of nanocomposite if they have some change of permeability. The conclusion is that air permeability increase as the quantity of nanotube increase. The five kinds of permeability the direction:H2>CO2>O2>N2>CH4.The influence of permeability will decrease when the quantity of carbon nanotube increase from 1.5% to 3% or 4%. We can get the conclusion that the increment of gas permeability isn’t limitary. It drifts towards maximal about 1.5%. H2 is 14.89barrer. CO2 is 9.51barrer. O2 is 6.34barrer. N2 is 6.48barrer. CH4 is 3.75 barrer.This experiment totally compared three groups of air selectivity. They ’re CO2/CH4, O2/N2 and H2/CH4. The maximum of selectivity is H2/CH4. The difference of kinetic diameter affects air selectivity a lot. The quantity of nanotube doesn’t associate with the air selectivity, but mixing too much nanotube will decrease air selectivity. The 1.5% nanocomposite has the highest selectivity. If the consistency of the membranes is higher than 1.5%, the air selectivity will decrease. Depend on the gas permeability and the air selectivity, the 1.5% nanocomposite has higher permeability and constant air selectivity. That shows the 1.5% nanocomposite has a better effect on air selectivity and recycling.


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奈米複合材料與空氣分子的愛恨情仇-探討奈米碳管對空氣滲透率之影響 1 MB Adobe Reader(Pdf)檔案