Ryan Emily A, Seibers Zach D, Reynolds John R, Shofner Meisha L
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
School of Chemistry and Biochemistry, Center for Organic Photonics and Electronics (COPE), Georgia Tech Polymer Network (GTPN), Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
ACS Appl Polym Mater. 2023 Jun 29;5(7):5092-5102. doi: 10.1021/acsapm.3c00588. eCollection 2023 Jul 14.
Thermoplastic polymers are a compelling class of materials for emerging space exploration applications due to their wide range of mechanical properties and compatibility with a variety of processing methods, including additive manufacturing. However, despite these benefits, the use of thermoplastic polymers in a set of critical space applications is limited by their low electrical conductivity, which makes them susceptible to static charging and limits their ability to be used as active and passive components in electronic devices, including materials for static charge dissipation, resistive heaters, and electrodynamic dust shielding devices. Herein, we explore the microstructural evolution of electrically conductive, surface-localized nanocomposites (SLNCs) of chemically modified reduced graphene oxide and a set of thermoplastic polymers as a function of critical thermal properties of the substrate (melting temperature for semi-crystalline materials or glass transition temperature for amorphous materials). Selected offsets from critical substrate temperatures were used to produce SLNCs with conductivities between 0.6-3 S/cm and surface structures, which ranged from particle-rich, porous surfaces to polymer-rich, non-porous surfaces. We then demonstrate the physical durability of these electrically conductive SLNCs to expected stress conditions for flexible conductive materials in lunar applications including tension, flexion, and abrasion with lunar simulant. Small changes in resistance (/ < 2) were measured under uniaxial tension up to 20% strain in high density polyethylene and up to 500 abrasion cycles in polysulfone, demonstrating the applicability of these materials as active and passive flexible conductors in exterior lunar applications. The tough, electrically conductive SLNCs developed here could greatly expand the use of polymeric materials in space applications, including lunar exploration, micro- and nano-satellites, and other orbital structures.
热塑性聚合物因其广泛的机械性能以及与包括增材制造在内的多种加工方法的兼容性，成为新兴太空探索应用中极具吸引力的一类材料。然而，尽管有这些优点，但热塑性聚合物在一系列关键太空应用中的使用却受到其低电导率的限制，这使得它们容易产生静电充电，并限制了它们作为电子设备中的有源和无源组件的使用能力，这些电子设备包括静电消散材料、电阻加热器和电动防尘屏蔽设备。在此，我们探索了化学改性还原氧化石墨烯与一组热塑性聚合物的导电表面局部纳米复合材料（SLNCs）的微观结构演变，该演变是作为基材关键热性能（半结晶材料的熔点或无定形材料的玻璃化转变温度）的函数。从关键基材温度选取的偏移量用于制备电导率在0.6 - 3 S/cm之间且表面结构各异的SLNCs，其表面结构从富含颗粒的多孔表面到富含聚合物的无孔表面不等。然后，我们展示了这些导电SLNCs在月球应用中对柔性导电材料预期应力条件（包括拉伸、弯曲以及与月球模拟物的摩擦）的物理耐久性。在高密度聚乙烯中，单轴拉伸至20%应变以及在聚砜中进行多达500次摩擦循环时，测量到电阻的微小变化（/ < 2），这表明这些材料作为月球外部应用中的有源和无源柔性导体具有适用性。在此开发的坚韧、导电的SLNCs能够极大地扩展聚合物材料在太空应用中的使用范围，包括月球探测、微型和纳米卫星以及其他轨道结构。
