Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/9893
標題: Characterization of The Flexible Substrate by PEN/MMT Nanocomposite Coated TiO2 Nanoparticles
聚對萘二甲酸乙二酯奈米複合材料塗佈二氧化鈦之可撓性基材製備與物性研究
作者: 劉淳亦
關鍵字: 聚對萘
PEN
二甲酸乙二酯
奈米複合材料
二氧化鈦
MMT
出版社: 材料工程學研究所
摘要: 本研究用改質奈米級MMT將PEN以熔融混練法製備成PEN/MMT奈米複合材料,以期增加其耐熱性和阻氣性。由TGA和DMA的結果發現,在1wt%MMT含量之PEN/MMT奈米複合材料其耐熱性有明顯的增加,但在分散較差之3wt%MMT含量的複合材料中則沒有更明顯的增加。而PEN/MMT奈米複合材料的透水率結果,發現MMT的添加使基材之透水率由11.5降至3.3 gm/m2‧day,降至原來之29%,表示MMT能增加水氣擴散路徑,有效延緩水氣的擴散和穿透。最後檢測PEN/MMT奈米複合材料其透光性的變化,量測範圍由可見光到紫外光波長,發現3wt%MMT含量之PEN/MMT奈米複合材料由原本88%降至73%的透光率,表示改質MMT之分散性會直接影響奈米複合材料的透光性。 另外PEN為結晶性高分子材料,必須研究改質MMT對PEN結晶行為的變化並進行分析,以有效控制PEN的微結構和其性質。發現添加改質MMT使PEN的晶相轉換溫度改變,造成β相在相對低結晶溫度的含量增加,且也使PEN的結晶速率增加,推論MMT的存在不但阻礙分子鏈運動,使複合材料較易生成熱穩定的β相,同時也會以成核劑的角色,使PEN的結晶速率增加。 由於MMT對降低PEN阻氣性的效果有限,所以再用電漿表面處理,增加PEN/MMT基材的表面粗糙度並改善其表面特性,以利之後阻絕層的披覆。阻絕層是用溶膠-凝膠法和高溫熱處理來製備二氧化鈦,再以其酒精溶液塗佈於PEN/MMT基材上,研究阻絕層對改善基材阻氣性之效果,發現3wt%MMT含量之PEN/MMT奈米複合材料其透水率由原本的8.35降至3.91 gm/m2‧day,降至原來之47 %。
PEN(polyethylene naphthalate) containing naphthalate structure exhibits superior tensile strength, thermal stability and low permeability. Thus they have been widely used as air-bag and recording tapes. However, PEN still has some undesirable properties that limit their application be a flexible substrate of display. In this report, we have used MMT as the dispersed phase to prepare PEN/MMT nanocomposites by melt-direct interaction of PEN into modified layered hosts. TGA, DMA, DSC, XRD, permeability and UV-visible spectrum have been used to analyze the properties of nanocomposite. From TGA and DMA results, they revealed that the heat stability in 1wt% content of PEN/MMT nanocomposite had been clearly increased, but it's not apparent for 3wt% content of PEN/MMT nanocomposite due to the worse dispersion. These results showed that the physical properties of nanocomposite would be directly revealed to crystalline feature and behavior of PEN. Both X-ray and DSC data reveal polymorphic behavior of PEN, depending on their thermal history. The parameter of crystallization kinetics determined by Avrami and Hoffman-Lauritzen theories were also discussed. Analyses from these theories indicated that PEN's phase transformed temperature shifted from 240℃ to lower temperature and increased crystallizatin rates while MMT was added. It was inferred that mobility of PEN's molecular chain which had been hindered by MMT to generates β-form crystals easily, and the increasing crystallizatin rates of PEN/MMT nanocomposite was also influence by MMT. From the measurement of permeability and UV-visible spectrum, PEN/MMT substrates have lower permeability than PEN. The addition of 3wt% MMT content of PEN/MMT was decreased the transparency from 88% to 73%. This result indicates that the dispersion of modified MMT affects the permeability and transparency of nanocomposites directly. Then PEN/MMT nanocomposite had been processed by nitrogen /oxygen plasma to increase the surface roughness of substrates which could be increased the adhesion between the substrate and barrier. Finally, nano-size of TiO2 particles were prepared by sol-gel method followed by thermal treatment and had been investigated by TEM and FESEM. From the TEM observation, and the particle sizes of TiO2 could be determined. The coated TiO2 on the surface of nanocomposite could be observed by FESEM and the addition of TiO2 layers on the surface of PEN/MMT nanocomposite could be further revealed the permeability from 8.35 to 3.91gm/m2‧day.
URI: http://hdl.handle.net/11455/9893
Appears in Collections:材料科學與工程學系

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