EVA/Clay奈米複合材料流變性質之研究

Rheological Properties of EVA/Clay Nanocomposites

詹勳涵(Hsun-Han Chan)

指導教授 ： 蘇淵源 ； 郭文正

國立臺北科技大學/工程學院/化學工程所/碩士(2005年)

摘要

本研究採用熔融插層技術，分別將兩種不同有機改質奈米黏土添加於乙烯-醋酸乙烯酯共聚物(EVA)中，製備EVA/黏土奈米複合材料。討論奈米黏土不同添加量對EVA/黏土奈米複材之材料結構、熱性質與流變性質的影響。其中以XRD及TEM分析奈米黏土在EVA基材中之分散狀態，以TGA及DMA分析其熱性質，再以旋轉式平行板流變儀進行奈米複材熔融態之動態與穩態各種流變實驗，並分析探討複材微結構與流變性質之關聯性。
經由XRD及TEM檢測得知，黏土呈現部分脫層與插層的型態分佈於EVA中，TGA測試也顯示添加奈米黏土對奈米複材的熱性質均有所提升，是由於奈米黏土在複材內以片狀分佈而產生屏蔽效應(barrier effect)。DMA分析結果顯示，隨著奈米黏土含量增加，其玻璃轉移溫度會有升高的趨勢。對於流變行為的探討，由於EVA中的VA插入矽酸鹽層內形成鏈結(tethered)，在動態頻率掃描實驗顯示，奈米複材的儲存模數與損失模數隨著奈米黏土含量的增加而上升，且對頻率的依附性，隨著奈米黏土含量的增加而減少。應力鬆弛時間亦會隨著黏土含量的增加而延後。由於高分子基材與黏土的交互作用與分散結構的影響，奈米複材的穩態剪切黏度會隨黏土含量增加而提高。

關鍵字

奈米黏土 ； 奈米複合材料 ； 熱性質 ； 流變性質

並列摘要

In this study﹐the EVA/organo-clay nanocomposites have been prepared by melt-blending organically modified montmorillonite (OMMT) with EVA﹒The structures of the nanoclay in these EVA/clay nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM)﹒The thermal properties of the obtained nanocomposites were analyzed by TGA and DMA﹒Subsequently﹐their melt rheological properties were measured with a parallel-plate rheometer of rotational type﹒With these results the relationship between the layered-structure of the nanoclay and the rheological properties was discussed﹒
XRD and TEM data were in support of the exfoliated and the intercalated structures of the nanocomposites﹒The thermal degradation temperature of these nanocomposites were increased obviously by the addition of nanoclay﹒The glass transition temperature were rised with the loading of nanoclay in DMA analysis﹒In the rheological behavior﹐the storage and loss moduli increase at all frequencies and show a frequency independent with increasing nanoclay loading because of the VA chains of EVA being tethered to the silicate surface﹒The stress relaxation time will also be postponed with increasing nanoclay content﹒In the steady rate sweep tests﹐the shear viscosity increase with the loading of nanoclay owing to the interaction between the polymer and the layered silicate﹒

並列關鍵字

nanoclay ； nanocomposite ； thermal propertiy ； rheological property

參考文獻

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