Study On Synthesis And Performance Of Conjugated Poly-Schiff Base And Its Iron Complexes

Schiff base mainly refers to a class of organic compounds,which contains imide or methylene amine groups.According to theory analysis and summary of previous research,it is considered to have a potential application in infrared-radar compatible stealth.In this paper,six kinds of conjugated Poly-Schiff base of different structure are synthesized,with diamine and dicarbonyl compounds.Then their iron complexes are synthesized respectively.Tests to character instructure and property of products are done.Poly-schiff base which has the best overall performance is mixed with carbon black to prepare compounds.The results reveal that there are some relationships among structure,conductivity,infrared emissivity and electromagnetic parameter.It is proved that adjusting conductivity of Schiff base can make infrared-radar compatible stealth come true.Following parts are included:(1)Six kinds of conjugated Poly-Schiff bases and their iron complexes are synthesized by glyoxal,p-phthalaldehyde,2,3-butanedione and p-phenylenediamine,2,6-diaminopyridine respectively.These products are characterized with meldometer,elemental analysis,nuclear magnetic resonance,infrared spectroscopy,molecular weight,ion content.Their conductivity,infrared emissivity and electromagnetic parameter are also measured.(2)Results show that those conjugated Poly-Schiff bases have so poor conductivity as 10-8 S·cm-1.When doped with FeCl3,the conductivity can be improved to 10-4~10-7 S·cm-1.That is 1~4 magnitudes,up to semiconductor level.Iron complexes(C6)has the best conductivity 1.16×10-4 S·cm-1,lowest infrared emissivity 0.733;Its dielectric loss tangent and magnetic loss tangent can reach 0.29 and 0.24 in 2~18 GHz,respectively.(3)P-phthalaldehyde shrinkage 2,6-diaminopyridine Poly-Schiff base is chosen to mix with carbon black to prepare compounds.Compounds are characterized by infrared spectrometer and scanning electron microscopy.Their conductivity,infrared emissivity and electromagnetic parameter are also measured.Results show that CB is in favor of the improvment of conductivity and reducing the infrared emissivity,optimizing the electromagnetic parameter.When CB accounting for 50%,Compounds have the best conductivity 1.62×10-1 S·cm-1,lowest infrared emissivity 0.699,more than 8 dB absorbing losses in 9.8~15.4GHz.