Fatigue superelastic successful development of the carbon nanofiber airgel
Having superelastic light fatigue resistance and compressible material, wherein in particular material to adapt to a wide temperature range, is an ideal material in the field of aerospace, mechanical buffer, and soft robot energy damping. Many low density polymeric foam is highly compressible, they tend to fatigue during repeated use, and super elastic polymer degradation occurs in the vicinity of the glass transition and melting temperature. 
Although researchers have developed a variety of thermally stable light metal and ceramic foam materials, they generally only have minimal reversible compressibility, and exhibit fatigue under cyclic deformation problems. Carbon nanotubes, and graphene by having superelastic and thermal stability inherent mechanical, in recent years, is used as the base material prepared lightweight superelastic material. Although there have been literature reports excellent correlation properties of such materials, equipment and manufacturing process but the complexity involved in work material can be prepared so as millimeter size. On the other hand, the complex nature of the hierarchy from hundreds of millions of biological materials evolved because of its excellent mechanical properties concern, however, since they are purely organic or organic / inorganic composite structure, generally only suitable for very narrow temperature work within the range. Therefore, these non-thermally stable structure of biological material into a thermally stable graphite material has an inherent hierarchy, is expected to create a thermodynamically stable material. December 23, reporters learned that the University of Science and Technology of China Yushu Hong Liang Haiwei team and a research group reported by pyrolysis of chemical control, the structure of biological materials (BC, ie bacterial cellulose) heat into graphite carbon nanofibers gas condensate method gum (CNFAs) a. Carbon aerogels prepared perfectly bacterial cellulose inherited from macro to micro level structure, having a significant thermal mechanical properties. Especially still remains superelastic at 2 × 106 After secondary compression cycles without plastic deformation, has excellent temperature does not vary with superelastic and fatigue resistance over a wide range of temperature range of at least -100–500 ℃. Such airgel thermal mechanical fatigue performance and stability than the polymer foam, ceramic foam, and metal foam has unique advantages and can achieve a large-scale synthesis, and biological material has economic advantages. Outcomes related to Temperature-Invariant Superelastic and Fatigue Resistant Carbon Nanofiber Aerogels published in \”advancedMaterial \”(Adv. Mater.) Journals. The team provides a use of inorganic bacterial cellulose (BC) chemical regulation method pyrolyzed to achieve a large-scale synthesis, shape retention carbonization new technology, the development of carbon nanofibers preferably airgel inherited bacterial cellulose structure factors from macro to micro level, does not show significant changes with temperature super-elastic and fatigue properties over a wide temperature range. Since the carbon nanofiber airgel has excellent thermal stability and mechanical properties prepared macro implemented in many areas will have important applications, particularly suitable for mechanical buffer under extreme conditions, a pressure sensor, a solar cell energy and aerospace damping Wait. Research was funded by the National Natural Science Foundation of Innovative Research Groups, the National Natural Science Foundation of China, Chinese Academy of frontier science research projects, Chinese Academy of nano-science innovation center of excellence, Suzhou Nanotech center of collaborative innovation. 
FIG. 1, the synthesis of macroscopic size CNFAs. (A) CNFAs process diagram of manufacturing; (b) pure BC and BC impregnating NH 4 H 2 PO 4 , (NH 4 ) 2 SO 4 , NH 4 Cl, (NH 4 ) 3 PO 4 [ 123], NaH 2 PO 4 or KH 2 PO 4 TG curves; different concentrations (c) of pure BC and BC impregnation NH 4 H 2 PO 4 after the TG curve; (d) pure BC and BC as a raw material, various amounts of NH at 800 ° C [ 123] 4 H 2 PO 4 preparation of carbonization CNFAs (NH 4 H 2 PO 4 0.5,4.8,16,44 weight ratio respectively and 62 wt%); (e) prepared at 1200 ℃ CNFAs density and conductivity; (f –g) C prepared at 800 ℃NFAs photographs showing its large scale can be prepared. FIG 2, when CNFAs at T = -100–500 ℃ N 2 thermodynamically stable mechanical properties 
in. (A – c) set was 20%, 40%, CNFAs compressive stress at 60% and 80% – strain curve, temperatures were: a) -100 ° C, b) 25 ° C, and c) 500 ° C ; viscoelasticity of (d) CNFAs at T = -100-500 ℃ (storage modulus, loss modulus and damping ratio); (E) the CNFA storage modulus, melamine, PU foams, and EPE changes with temperature; (f) the storage modulus and loss modulus CNFAs at 1 × 105 cycles of different temperatures.
