Hybrid conducting composites comprising thermoplastic polyurethane (TPU) and mixtures of carbon black modified with polypyrrole (CB-PPy) and carbon nanotubes (CNT) were prepared by melt mixing process. The electrical conductivity, rheological properties and electromagnetic shielding effectiveness (EMI SE) of TPU/CB-PPy and TPU/CNT composites were also investigated those results observed for TPU/CB-PPy/CNT hybrid composites. TPU/CNT composites show a very sharp insulator-conductor transition and the electrical percolation threshold was about 1 wt% of CNT, which was lower than that found for TPU/CB-PPy (7 wt%). Moreover, EMI SE values of TPU/CNT composites were higher than those for TPU/CB-PPy due to the denser CNT conductive pathway into TPU matrix. In order to achieve the highest electrical conductivity and EMI SE values, mixtures of CB-PPy/CNT were added in the composites in different mass fractions. In fact, the electrical conductivity values increased by combining CB-PPy and CNT, resulting in hybrid composites of TPU/CB-PPy/CNT with higher EMI SE values when compared to TPU/CB-PPy composites. The present study demonstrates the potential use of hybrid polymer composites containing 5 or 8 wt% of CB-PPy/CNT at specific CB-PPy/CNT ratios with good processabilty and EMI SE values as high as −20 dB indicating the potential use of these materials for electromagnetic shielding application in the X-band frequency region.

通过熔融混合法制备了包含热塑性聚氨酯（TPU）以及用聚吡咯改性的炭黑（CB-PPy）和碳纳米管（CNT）的混合物的混合导电复合材料。还研究了TPU / CB-PPy和TPU / CNT复合材料的电导率，流变性能和电磁屏蔽效能（EMI SE）。TPU / CNT复合材料显示出非常尖锐的绝缘体-导体过渡，电渗流阈值约为CNT的1 wt％，低于TPU / CB-PPy（7 wt％）。此外，由于进入TPU基体的CNT导电路径更密集，因此TPU / CNT复合材料的EMI SE值高于TPU / CB-PPy。为了获得最高的电导率和EMI SE值，将CB-PPy / CNT的混合物以不同的质量分数添加到复合材料中。实际上，通过结合CB-PPy和CNT可以提高电导率值，从而导致与TPU / CB-PPy复合材料相比，TPU / CB-PPy / CNT的混合复合材料具有更高的EMI SE值。本研究表明，在特定的CB-PPy / CNT比下，含有5或8 wt％的CB-PPy / CNT的杂化聚合物复合材料的潜在用途以及良好的加工性和EMI SE值高达-20 dB，表明了这些材料的潜在用途X波段频率区域的电磁屏蔽材料。