Vehicles and equipment launched into space require advanced materials with enhanced properties to withstand the rigors of outer space. Exploring the potential of carbon-reinforced polymers for use in space, a research paper was published, which was included in Recent advances in manufacturing processes and systems.
Study: Hybrid nanotubes and graphene oxide in the development of CFRP for space use. Image Credit: porti/Shutterstock.com
Develop advanced materials for use in space
The space industry uses several advanced materials such as Kevlar, aluminum alloys, ceramics and Invar. Materials used in components must possess specific electrical and thermal characteristics due to the rigors of outer space. However, despite their superior electrical and thermal performance, many metals used in components have high density and can be expensive to manufacture.
Carbon-based nanofillers such as graphene oxide, single-walled carbon nanotubes, and multi-walled carbon nanotubes and their combinations have been widely explored to replace conventional materials. These classes of nanomaterials possess superior electrical and thermal conductivities and are durable and inexpensive to produce. They confer significant advantages for the design of components intended for use in vehicles and equipment in the harsh environments of outer space.
The importance of electrical and thermal conductivity
Equipment that goes into space requires specific material properties in its construction. Radio frequency applications benefit from materials with good electrical conductivity that allow the electroplating of highly conductive metals onto CFRP laminates. In addition, electrical conductivity is an important property for the electromagnetic shielding of payload elements and is necessary for electrical performance compliance.
Thermal conductivity is particularly important for payload elements because it dissipates the heat they generate, preventing damage to vital systems and improving the safety of people on board space vehicles. Therefore, materials that possess both superior electrical and thermal characteristics are central to the design of payload elements and other components intended for use in outer space.
Examples of how carbon nanomaterials improve these properties
Each type of carbon nanomaterial has different characteristics that can improve thermal and electrical conductivity, making them attractive candidates as advanced materials for space exploration.
For example, carbon nanotubes can be embedded in carbon fiber reinforced polymers. Different concentrations of these nanofillers give the material varying electrical conductivities. Moreover, the hybridization of multi-walled carbon nanotubes and reduced graphene oxide improves the thermal conductivity of materials due to the presence of carbon-carbon covalent bonds. Phonons transmit faster in covalent bonds compared to non-covalent Van der Waals bonds.
The transport of phonons is directly proportional to the thermal conductivity of the material. The large contact area of graphene oxide with multi-walled carbon nanotubes is due to its multiple inner layers, and moreover, it actively participates in phonon transport with minimal coupling loss. Graphene oxide stabilizes multi-walled carbon nanotubes, as indicated by the uniform dispersion of the complexes without precipitation at room temperature.
There is a relationship between electrical and thermal conductivity in these hybrid systems that is related to the ratio of multi-walled carbon nanotubes to reduced graphene oxide. The thermal conductivity is highest in the across-plane direction, while a minimum value in the in-plane direction gives these hybrid materials the maximum electrical conductivity.
The study aimed to improve advanced materials based on carbon nanomaterials for use in space exploration. In the study, researchers investigated the enhancement of thermal and electrical conductivity of carbon fiber reinforced polymers by including different concentrations of reduced graphene oxide and multi-walled carbon nanotubes. Additionally, they explored different nanofillers that can be incorporated into carbon fiber reinforced polymers.
The thermal and electrical characterization of composite materials with different concentrations of multi-walled carbon nanotubes and reduced graphene oxide was carried out by the authors. They characterized resistivity, shielding effectiveness, thermal expansion and thermal conductivity. Advantageous characteristics of new carbon nanofiller/polymer composite materials have been observed.
Silver electroplating was performed as a surface treatment process on the samples to test their performance under conditions typically found in outer space. A peel test was performed on the samples, with no plating degradation observed by the authors, demonstrating the suitability of the proposed materials for payload components in space vehicles.
The results of the material characterization and physical tests carried out as part of the research revealed a class of composite materials with improved thermal and electrical conductivity. The authors said their results show that carbon fiber-reinforced polymers incorporating multi-walled carbon nanotubes and reduced graphene oxide warrant further evaluation for applications in the space industry.
Additionally, they said the data gathered from their research will be essential for the fabrication of new low-power feed horns, RF reflectors and carrier plates for use in future space research projects.
Solanki, JD (2022) Hybrid nanotubes and graphene oxide in the development of CFRP for space use [online] Recent advances in manufacturing processes and systems pages 545-553 | link.springer.com. Available at: https://link.springer.com/chapter/10.1007/978-981-16-7787-8_44