碳系複合材料電磁波屏蔽效益之研究

A Study of Electromagnetic Shielding Effect of Carbon Series Composites Effectiveness

王馨(Hsin Wang)

指導教授 ： 鄭大偉

國立臺北科技大學/工程學院/材料及資源工程系所/碩士(2006年)

摘要

電磁波是近幾十年來發現的一種新污染，它是一種看不見、聽不到、摸不著的無形污染；隨著3C電子產品使用率之提升，人體接觸電磁波的機會也愈來愈多。有鑑於此，為了有效降低電磁波干擾及影響，選用質輕的金屬材料或導電性高分子複合材料，是目前屏蔽電磁波之重要發展方向。一般高分子材料具有良好的絕緣性，同時高分子材料具有質輕、美觀、加工成型容易及價格便宜等多項優點。高分子材料若添加導電性填充劑(如碳黑、碳纖維)，並依照不同電阻需求，可製造出不同功能之導電性高分子材料，因此高分子複合材料已被廣泛的應用做為電磁波屏蔽材。
本研究係將碳系導電性粉末：碳黑、碳纖維及奈米碳管，分為單型及複型填充材兩大類，進行填充粉末之分散處理，再以高分子混摻法添加至聚氨基甲酸酯（Polyurethane，PU）中，經塗佈法製成PU複合薄膜。此薄膜內部因導電碳系粉末的添加而形成導電網絡，進而使其薄膜得到電磁波屏蔽之效果。
依據實驗結果顯示，填充量相同之條件下，其電磁波屏蔽效果，以碳黑/碳纖維/奈米碳管三種碳系填充材混合所製成之PU複合薄膜最佳；此外，薄膜厚度亦決定其導電及電磁波屏蔽性質。本研究所製成碳黑/碳纖維/奈米碳管之複型複合薄膜，在填充量20 vol%，厚度僅有0.35 mm時，其電磁波屏蔽效益最高可達33dB，遮蔽效率為99.9％。

關鍵字

導電性粉末 ； 聚氨基甲酸酯 ； 複合薄膜 ； 電磁波屏蔽

並列摘要

In recent decades, the electromagnetic wave is discovered as a formless hazardous pollutant, invisible, unsounded and untouchable. Due to the wide application of 3C electronic product, it is inevitable for human being to contact the electromagnetic wave more often than ever. With a great aim to reduce the intervention and influence of the electromagnetic wave to the minimum, the light metallurgical material or the high conductive composite is favorably considered as a major research project in an effort to develop an effective electromagnetic shielding material.
Polymers, in general, are outstanding insulation materials embracing a great number of superb characteristics, such as light weight, good looking appearance, easy formation and low prices. Polymers can be easily converted to highly conductive material by adding electric conductivity particles to produce a variety of conductive polymers, widely used as EMI shielding composites. This study mainly concerns to disperse the carbon black, carbon fiber and carbon nanotube within main body of the polyurethane (PU). A thin film is thereby formed and EMI shielding effect in the conductive network is also achieved with extremely success.
The experiment result shows that the mixture of carbon black, carbon fiber and carbon nanotube will obtain better shielding effect. In addition, the thickness of the film is significant to the performance of the conductivity and electromagnetic shielding. This experiment has produced a composite film from polyurethane containing 20% volume of carbon black, carbon fiber and carbon nanotube in the thickness of 0.35 mm and the electromagnetic shield effect is as high as 33 dB.

並列關鍵字

Conductive powders ； Polyurethane ； Composite films ； Electromagnetic Shielding Effect

參考文獻

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