Synthesis, conductivity, and electromagnetic wave absorption properties of chiral poly Schiff bases and their silver complexes

Four chiral poly Schiff bases were synthesized via polycondensation between l- lysine and p-benzoquinone, 1,4-naphthoquinone, dibenzoyl, and 2,3-butanedione, respectively. Subsequently, the silver coordination polymers of the chiral poly Schiff base were prepared upon silver ions coordinating with the chiral poly Schiff bases. The structures of the polymers were characterized with IR, UV-vis, GPC, elemental analysis, and optical activity analysis. The properties of polymers were studied through conductivity testing and electromagnetic parameter testing. The results show that they own good electrical conductvities, and the electrical conductivity of chiral poly-( l- lysine(2,3-butanedione)) Schiff base silver complex can reach 3.7 × 10 2 S/cm. The electromagnetic wave absorption properties of four silver complexes were calculated using transmission line theory, the maximum reflection loss of chiral poly-( l- lysine(p-benzoquinone)) Schiff base silver complex can reach −45.9 dB at a thickness of 5 mm, while that of achiral poly-( dl -lysine(p-benzoquinone)) Schiff base silver complex is −20.1 dB at a thickness of 5 mm. The enhanced microwave absorbing properties were attributed to the chiral feature. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42498.