Polyimide (PI) is widely used in aerospace applications due to its excellent properties. However, the high concentration of atomic oxygen (AO) in low-earth orbit (LEO) significantly degrades its performance. This study employs reactive molecular dynamics (MD) simulations to analyze the AO erosion resistance of fluorinated polyimide (FPI) and polyhedral oligomeric silsesquioxane (POSS) composite polyimide models. The 35 ps simulation results indicate that the PI/POSS composite exhibits the best protective performance. The protection mechanism involves the formation of an SiO carbonized layer that prevents the transmission of AO and heat to the polyimide matrix, resulting in a normalized mass of 84.1% after erosion. The FPI model shows the second-best protective effect, where the introduction of -CF groups enhances the thermal stability of the polyimide matrix, resulting in a normalized mass of 80.7% after erosion. This study explores the protective effects and mechanisms of different polyimide protection methods at the molecular level, providing new insights for the design of AO erosion protection systems.
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http://dx.doi.org/10.3390/polym16121687 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
December 2024
School of Agriculture and Bioengineering, Heze University, Heze 274500, China. Electronic address:
Herin, the successful synthesis of a bis Schiff base (L) has been achieved using 2-hydroxy-1-naphthaldehyde and 1,3-diaminoguanidine as raw materials, which was further characterized by infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance hydrogen spectrum. Moreover, spectroscopic experiments demonstrated that the probe L showed good selectivity and visual detectability for Al. Its detection limit (DL) is 2.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
TCS Research, Sahyadri Park 2, Rajiv Gandhi Infotech Park, Hinjewadi Phase 3, Pune 411057, India.
Realization of a sustainable hydrogen economy in the future requires the development of efficient and cost-effective catalysts for its production at scale. MXenes (MX) are a class of 2D materials with 'n' layers of carbon or nitrogen (X) interleaved by 'n+1' layers of transition metal (M) and have emerged as promising materials for various applications including catalysts for hydrogen evolution reaction (HER). Their properties are intimately related to both their composition and their atomic structure.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300401, PR China; Engineering Research Center of Ministry of Education for Intelligent Rehabilitation Device and Detection Technology, Hebei University of Technology, Tianjin 300401, PR China; Hebei Key Laboratory of Smart Sensing and Human-Robot Interaction, Hebei University of Technology, Tianjin 300401, PR China; School of Mechanical Engineering, Hebei University of Technology, 5340 Xiping Road, Beichen District, Tianjin 300401, PR China. Electronic address:
Transition-metal-loaded carbon-based electrocatalysts are promising alternatives to conventional precious metal electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in high-performance zinc-air batteries. However, efficiently doping transition-metal single atoms onto carbon-based frameworks is a significant challenge. Herein, an improved template-sacrificing method combining a two-step carbonization process is proposed to fabricate Cu/Co diatomic sites coanchored on a three-dimensional nitrogen-doped carbon-based framework.
View Article and Find Full Text PDFNanotechnology
December 2024
CCTS/DFQM, UFSCar - Campus Sorocaba, Rod. João Leme dos Santos km 110 - SP-264 Bairro do Itinga - Sorocaba CEP 18052-780, Sorocaba, 18052-780, BRAZIL.
Nanomaterials stand out for their exceptional properties and innovative potential, especially in applications that protect against space radiation. They offer an innovative approach to this challenge, demonstrating notable properties of radiation absorption and scattering, as well as flexibility and lightness for the development of protective clothing and equipment. This review details the use of polymeric materials, such as polyimides (PIs), which are efficient at attenuating ultraviolet (UV) radiation and atomic oxygen (AO).
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
Departament de Ciència de Materials i Química Física, Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, C/Martí i Franquès 1-11, 08028 Barcelona, Spain.
The separation of oxygen (O) and nitrogen (N) from air is a process of utmost importance nowadays, as both species are vital for numerous fundamental processes essential for our development. Membranes designed for their selective molecule separation have become the materials of choice for researchers, primarily due to their ease of use. The present study proposes grazynes, 2D carbon-based materials consisting of and C atoms, as suitable membranes for separating O and N from air.
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