- 學位論文
不同VA含量之EVA/clay奈米複合材料流變性質之研究
Rheological Properties of Different Vinyl Acetate Content and Nanoclay Loading on EVA Nanocomposites
摘要
本研究採用熔融插層技術，分別將有機改質奈米黏土添加於不同VA含量的乙烯-醋酸乙烯酯共聚物（Ethylene Vinyl Acetate copolymer，EVA）中製備奈米複合材料。討論奈米黏土添加在不同VA含量的EVA中對EVA/黏土奈米複合材料之材料結構、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測試中顯示添加奈米黏土在不同VA含量的EVA中對熱性質均有所提升，但因為VA含量的不同造成奈米複材熱性質提昇程度上有所差異。對於流變行為的探討，在動態頻率掃描實驗顯示，在不同VA含量的EVA/黏土奈米複材中儲存模數與損失模數會隨著奈米黏土含量的增加而上升，且VA含量較高的EVA/黏土奈米複材提升的效果較高，對頻率的依附性，會因為奈米黏土含量的增加及較高的VA含量而減少。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，在穩態剪切黏度實驗中顯示，剪切黏度會因為黏土含量增加而提高，且VA含量較高的EVA/黏土奈米複材會有較好的效果。
並列摘要
In this study﹐two EVAs with different VA contents were melt blended with organically modified montmorillonite (OMMT) to obtain polymer layered silicate nanocomposites﹒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﹒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﹒ The intercalated and the partially exfoliated structures of the nanocomposites were characterized by XRD and TEM﹒The thermal degradation temperature of these nanocomposites were increased obviously by the addition of nanoclay﹒In the rheological behavior﹐the storage and loss moduli increase at all frequencies and show a frequency independent with increasing nanoclay loading, and that with the higher VA content is better than that with the lower﹒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 , and that with the higher VA content still has better effect.