Skin collagen fiber-based radar absorbing materials

Abstract

By using skin collagen fiber (CF) as raw material, Schiff base structure containing CF (Sa-CF) was synthesized through CF-salicylaldehyde reaction. Then a novel radar absorbing material (Fe-Sa-CF) was prepared by chelating reaction between Sa-CF and Fe 3+. The coaxial transmission and reflection method was used to analyze the complex permittivity and complex magnetic permeability of these CF-based materials, and the radar cross section (RCS) method was used to investigate their radar absorbing properties in the frequency range of 1.0-18.0 GHz. Experimental results indicated that the conductivity of CF increased from initial 1.08×10-11 to 2.86×10 -6 S/cm after being transferred into Fe-Sa-CF, and its dielectric loss tangent (tanδ) in the frequency range of 1.0-17.0 GHz also increased. These facts suggest that the Fe-Sa-CF is electric-loss type radar absorbing material. In the frequency range of 3.0-18.0 GHz, Sa-CF (1.0 mm in thickness) exhibited somewhat radar absorbing property with maximum radar reflection loss (RL) of -4.73 dB. As for Fe-Sa-CF, the absorbing bandwidth was broadened, and the absorbing intensity significantly increased in the frequency range of 1.0-18.0 GHz where a maximum radar RL of -9.23 dB was observed. In addition, the radar absorbing intensity of Fe-Sa-CF can be further improved by increasing membrane thickness. When the thickness reached to 2.0 mm, the RL values of Fe-Sa-CF were -15.0−-18.0 dB in the frequency range of 7.0-18.0 GHz. Consequently, a kind of novel radar absorbing material can be prepared by chemical modification of collagen fiber, which is characterized by thin thickness, low density, broad absorption bandwidth and high absorption intensity. skin collagen fiber, chemical modification, radar absorbing material, reflection loss (RL) Citation:Liu Y S, Huang X, Guo P P, et al. Skin collagen fiber-based radar absorbing materials.

The Retention and Drainage Behavior of Cross-linked Gelatin with Glutaraldehyde in a Papermaking System

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A Biodegradable Flexible Micro/Nano-Structured Porous Hemostatic Dental Sponge

“…The FTIR results showed all functional groups of gelatin; 1638 cm −1 , 1544 cm −1 , 1244 cm −1 , and 3433 cm −1 represented the amide I, II, and III bands of gelatin, respectively [33,34]. We used glutaraldehyde as a cross-linking agent.…”

“…The amide I peak for gelatin powder (1638 cm −1 ) in the sponge sample becomes smaller and also had a shift to 1620 cm −1 . This result implied that gelatin reacted with glutaraldehyde, resulting in the formation of a Schiff base, indicating cross-linking with glutaraldehyde [33,34]. Indeed, the (-CHO) aldehyde group of glutaraldehyde interacts with the lysine amine groups of gelatin proteins [36].…”

Multilayer Structure Ammoniated Collagen Fibers for Fast Adsorption of Anionic Dyes

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