本研究是以添加陽離子界面活性劑溴化十六烷基三甲銨(Hexadecyltrimethylammonium bromide, CTAB)，並以原位化學氧化聚合製備出石墨烯奈米片(Graphene nanoplatelet, GNP)/多壁奈米碳管(Multi-walled carbon nanotube, MWCNT)/聚吡咯(Polypyrrole, PPy)混合填料。接著以聚氨酯 (Polyurethane, PU)作為高分子基體混和製備GNP/MWCNT/PPy/PU奈米複合材料。藉由混和填料的協同作用來提升導電性能，以及GNP、MWCNT、PPy及PU之間的界面極化等，增強電磁屏蔽(Electromagnetic interference shielding effectiveness, EMI SE) 效能。我們找出製備具三維奈米結構GNP/MWCNT/PPy的最佳配比，成功製備出一維的MWCNT/PPy奈米線佈滿在二維GNP/ PPy的奈米層上。此外，相互連接形成GNP/MWCNT/PPy的三維奈米結構，在絕緣體聚氨酯中發展形成GNP-PPy-MWCNT-PPy-GNP的連續導電網絡結構的奈米複合材料。因此在30 MHz至1,800 MHz的頻率範圍測試獲得EMI SE為35~40dB，已可遮蔽掉99.9%以上的電磁波，具有商業化應用之潛力。

This study reports the preparation of graphene nanoplatelet (GNP)/multiwalled carbon nanotube (MWCNT)/polypyrrole (PPy) hybrid fillers via in the chemical oxidative polymerization, with the addition of a cationic surfactant (hexadecyltrimethylammonium bromide, CTAB). These hybrid fillers were incorporated into polyurethane (PU) to prepare GNP/MWCNT/PPy/PU nanocomposites. The electrical conductivity of the nanocomposites was enhanced by the synergy of hybrid fillers to increase the efficacy of EMI SE. We found the optimal formulation for the preparation of GNP/MWCNT/PPy 3D nanostructures and utilized this to successfully prepare GNP/PPy nanolayers (2D) extensively covered by MWCNT/PPy nanowires (1D). Additionally, when GNP/MWCNT/PPy 3D nanostructures were incorporated into a PU matrix, these would form a nanocomposite of a continuous network of conductive PPy–CNT–PPy–MWCNT–GNP paths. The results show that the nanocomposites greatly enhances the reflectance and attenuation of electromagnetic waves and the obtained EMI SE can reach 35-40 dB between 30-1,800 MHz, which will shield over 99.9% of all electromagnetic waves. Therefore, this EMI shielding composite has excellent prospects for commercial use.

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