Bipolar plates in phosphoric acid fuel cells require inertness to phosphoric acid as well as excellent electrical, thermal, and mechanical properties. For this application, we prepared poly(phenylene sulfide) (PPS)-graphite composites with random or ordered graphite orientations by compression and extrusion-compression processes, respectively. Due to current limitations of extruding graphite-filled polymers, only moderately high graphite concentrations were used (up to 40 wt%). The compressed composites contained graphite sheets in a planar orientation (parallel to the pressing direction) and exhibited highly anisotropic electrical and thermal conductivity, with much higher in-plane than through-plane components. In contrast, composites that were extruded prior to compression exhibited randomly oriented graphite due to shearing forces during extrusion and therefore displayed isotropic properties. Thus, their through-plane electrical and thermal conductivity was superior to those of the ordered composite, while the in-plane properties were inferior. Notably, the internal graphitic structure affected the electrical conductivity more than the thermal conductivity. The randomly oriented composite also exhibited superior flexural strength, although the thermal stability of the two composites was almost equal. This study offers insights into the structure-property relationship of PPS-graphite composites as well as the effect of the orientation of conductive two-dimensional fillers on anisotropic properties.

中文翻译：

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用于具有优选形态取向的双极板的聚苯硫醚-石墨复合材料

磷酸燃料电池中的双极板需要对磷酸具有惰性以及优异的电、热和机械性能。对于此应用，我们分别通过压缩和挤出-压缩工艺制备了具有随机或有序石墨取向的聚苯硫醚 (PPS)-石墨复合材料。由于目前挤出石墨填充聚合物的限制，仅使用了中等高的石墨浓度（高达 40 wt%）。压缩的复合材料包含平面取向（平行于压制方向）的石墨片，并表现出高度各向异性的导电性和导热性，面内比贯通面组件高得多。相比之下，在压缩之前挤出的复合材料由于挤出过程中的剪切力而表现出随机取向的石墨，因此表现出各向同性的特性。因此，它们的面内导电性和导热性优于有序复合材料，而面内性能较差。值得注意的是，内部石墨结构对电导率的影响大于对热导率的影响。尽管两种复合材料的热稳定性几乎相同，但随机取向的复合材料也表现出优异的弯曲强度。这项研究提供了对 PPS-石墨复合材料的结构-性能关系以及导电二维填料的取向对各向异性性能的影响的见解。它们的面内导电性和导热性优于有序复合材料，而面内性能较差。值得注意的是，内部石墨结构对电导率的影响大于对热导率的影响。尽管两种复合材料的热稳定性几乎相同，但随机取向的复合材料也表现出优异的弯曲强度。该研究提供了对 PPS-石墨复合材料的结构-性能关系以及导电二维填料的取向对各向异性性能的影响的见解。它们的面内导电性和导热性优于有序复合材料，而面内性能较差。值得注意的是，内部石墨结构对电导率的影响大于对热导率的影响。尽管两种复合材料的热稳定性几乎相同，但随机取向的复合材料也表现出优异的弯曲强度。这项研究提供了对 PPS-石墨复合材料的结构-性能关系以及导电二维填料的取向对各向异性性能的影响的见解。内部石墨结构对电导率的影响大于对热导率的影响。尽管两种复合材料的热稳定性几乎相同，但随机取向的复合材料也表现出优异的弯曲强度。这项研究提供了对 PPS-石墨复合材料的结构-性能关系以及导电二维填料的取向对各向异性性能的影响的见解。内部石墨结构对电导率的影响大于对热导率的影响。尽管两种复合材料的热稳定性几乎相同，但随机取向的复合材料也表现出优异的弯曲强度。这项研究提供了对 PPS-石墨复合材料的结构-性能关系以及导电二维填料的取向对各向异性性能的影响的见解。