Ca2+辅助增强CNT/PEEK界面结合及其导电复合材料制备与性能

Ca2+ assisted enhancement of CNT/PEEK interfacial bonding and its conductive composites preparation and performance study

  • 摘要: 作为特种工程塑料,聚醚醚酮(PEEK)凭借高比强度、耐腐蚀、耐高温性能引起人们的研究兴趣。但PEEK的绝缘性限制了其在传感、防静电及电磁吸收等领域的应用。利用碳纳米管(CNT)作为增强体,同时提高PEEK的导电性能和力学性能已被公认为是一种行之有效的方法。然而由于CNT和PEEK表面均具有较强惰性,且两者适用的分散体系不同,从而严重影响了CNT/PEEK复合材料的性能。基于此,本文通过乙醇-去离子水二元溶剂提高酸化CNT (aCNT)和PEEK粉体的分散性,并利用金属阳离子Ca2+作为中间体桥联aCNT与PEEK,制备树脂未改性的aCNT-Ca2+/PEEK复合粉体,进而通过热压工艺得到了高导电、力学性能增强的aCNT-Ca2+/PEEK复合材料。通过FTIR、XPS、Zeta电位等测试深入探究了Ca2+桥联PEEK与aCNT的作用机制。结果表明:加入Ca2+后,aCNT能够均匀地吸附在PEEK表面,形成核壳结构的复合粉体,利用此复合粉体热压后可得到多通道三维导电网络。制得的复合材料导电渗流阈值为1.5wt%,此时的电导率为9.9×10−4 S/cm,相较于纯PEEK树脂电导率提升了近12个数量级;aCNT含量为5wt%时,电导率达到最大值3.5×10−2 S/cm。在填料含量为1wt%时,复合材料拉伸强度达到最大,为92.87 MPa,相比于纯PEEK树脂提升了15.7%。此外,该导电复合材料具有良好的温敏特性,其温度-电导率在不同升温方式、多次升温过程中路径保持一致,表现出稳定的传感特性。因此,本文制备的aCNT-Ca2+/PEEK复合材料在导电、力学性能增强及温度感知等方面有巨大应用潜力。

     

    Abstract: Poly ether ether ketone (PEEK) is a high-performance engineering polymer that has garnered attention from researchers because of its remarkable specific strength, good corrosion resistance, and high temperature resistance. However, its insulating qualities restrict its use in applications like electromagnetic absorption, anti-static, and sensing applications. CNT reinforcement has been acknowledged as a successful technique for concurrently enhancing the mechanical properties and electrical conductivity of PEEK. Nevertheless, because of the high inertness of the PEEK and CNT surfaces as well as the different dispersing systems, it is difficult to disperse CNT in the PEEK matrix. This has a significant negative effect on the performance of CNT/PEEK composites. Based on this, in this study, ethanol-deionized water binary solvent was used to improve the dispersion of acidified CNT (aCNT) and PEEK powders. Ca2+ was then used as an intermediate to bridge aCNT and PEEK to prepare aCNT-Ca2+/PEEK composite powders, which were then hot-pressed to produce highly conductive, mechanically enhanced aCNT/PEEK composites. FTIR, XPS, and Zeta potential experiments were used to thoroughly analyze the mechanism of Ca2+ bridging PEEK with aCNT. The findings demonstrate that, with the addition of Ca2+, aCNT can uniformly adsorb on the surface of PEEK, which produces a composite powder with a core-shell structure. By hot pressing this composite powder, a multi-channel three-dimensional conductive network may be produced. The obtained composite exhibits a conductivity of 9.9×10−4 S/cm at the conductive percolation threshold of 1.5wt%, which is over 12 orders of magnitude higher than the conductivity of pure PEEK resin; The conductivity increased to 3.5×10−2 S/cm at a 5wt% aCNT concentration. The composites reached their maximum tensile strength of 92.87 MPa at a 1wt% filler, a 15.7% increase over the pure PEEK resin. Furthermore, the conductive composite exhibits good temperature-sensitivity qualities, and its temperature-conductivity paths remain consistent across different heating methods and multiple heating processes, demonstrating stable sensing characteristics. Therefore, the aCNT-Ca2+/PEEK composites show great promise in temperature sensing, mechanical enhancement, and electrical conductivity.

     

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