超臨界二氧化碳發泡製備法奈米孔徑之熱塑性聚氨酯奈米複合材料研究

Production of Nanoporous Thermoplastic Polyurethane Nanocomposites by Supercritical Carbon Dioxide

劉宇哲(Yu-Che Liu)

指導教授 ： 葉樹開

國立臺北科技大學/工程學院/化學工程研究所/碩士(2012年)

摘要

本研究是利用超臨界二氧化碳製造TPU發泡材料，並探討其操作條件如含浸溫度與泡孔形態之關係。之後在熱塑性聚氨酯中添加少量不同的無機奈米顆粒，製備成奈米複合發泡材料，觀察其泡孔形態，找尋最佳之奈米填充材料。將TPU奈米複合材料進行分散形態、黏度、力學性質等表徵之測試。最後，也將TPU奈米複合發泡材料進行力學性能之測試，探討泡孔型態對力學性能之影響。
實驗結果顯示，在TPU內添加五種不同的奈米顆粒(Clay30B、Clay20A、CNT、CNF、H05)，以Clay30B作為異相成核劑之效果最好，明顯縮小泡孔及提升泡孔密度。添加Caly30B含量增加，cell density上升，且foam density隨之下降，而含浸溫度下降到50℃，成功獲得cell size小至450nm之奈米泡，且cell density維持在1011cells/cm3。添加奈米顆粒可以增加材料之機械性質，經拉伸試驗結果，在未發泡時Clay30B添加量提升，楊氏模數和降伏強度上升，但是斷裂伸長率會下降。而材料經發泡程序後，泡孔大小會影響材料之機械性質，當泡孔小至數百奈米時，其機械性質下降程度也愈小，添加1wt%的Clay30B可以增加發泡體的楊氏模數和降伏強度，而且材料的斷裂伸長率不變。因此可以利用含浸溫度及Clay30B含量來操控泡孔大小和發泡材之密度，獲得理想之發泡材料。

關鍵字

TPU ； 成核劑 ； 奈米複合材料 ； 奈米黏土 ； 泡孔大小 ； 泡孔大小 ； 奈米泡 ； 機械性質

並列摘要

In this study, thermoplastic polyurethane (TPU) was foamed by batch foaming using CO2 as the blowing agent, and the effect of saturation temperature on cell morphology TPU foam was examined. Five different nanoparticles were compounded with TPU as the nucleation agent. Among the five different nanoparticles(Clay30B、Clay20A、CNT、CNF、H05), Clay30B seems to be the best nucleation agent, because it had the smallest cell size and the highest cell density in the result of batch foaming.
Adding 1wt% 30B nanoclay resulted in submicron sized foam. With the increasing content of Clay30B led to increase in the cell density, while the foam density decreases. The cell size could be as low as 450 nm while the cell density could be as high as 1011 cells/cm3.
Finally, the effect of cell morphology to the mechanical properties of foamed samples was also investigated. It was found that adding 1wt% nanoclay not only could improve the mechanical properties of the solid, it can also increase the modulus of the foamed nanocomposite significantly.

並列關鍵字

TPU ； nucleation agent ； nanocomposites ； nanoclay ； cell size ； cell density ； nanofoam ； mechanical properties

參考文獻

4 K. T. Okamoto, Microcellular Processing, Cincinnati: Hanser Gardner Publications, 2003.

5 P. C. Lebaron, Z. Wang, T. J. Pinnavaia, "Polymer-layered silicate nanocomposites: An overview," Applied Clay Science, vol. 15, 1999, pp. 11-29.

8 M. Okamoto, P. H. Nam, P. Maiti, T. Kotaka, T. Nakayama, M. Takada, M. Ohshima, A. Usuki, N. Hasegawa, H. Okamoto, "Biaxial flow-induced alignment of silicate layers in polypropylene/clay nanocomposite foam," Nano Letters, vol. 1, 2001, pp. 503-505.

9 S. T. Lee, N. S. Ramesh. Polymeric Foams Mechanisms and Materials; CRC Press, 2004.

12 C. B. Wang, S. L. Cooper, "Morphology and properties of segmented polyether polyurethaneureas," Macromolecules, vol. 16, 1983, pp. 775-786.