Novel conducting polySchiff base of N-(3-aminopropyl) pyrrole-salicylaldehyde and its copolymers with pyrrole: synthesis and characterization

Abstract

Novel Schiff base polymer of N-(3-aminopropyl) pyrrole-salicylaldehyde and its copolymers with pyrrole were synthesized by interfacial polymerization, ultrasonic method, and electrochemical polymerization with the aim of producing and characterizing a new class of polymeric materials which could be used as separator of heavy metals such as Cu²⁺ and Ni²⁺. For this purpose, Schiff base structure was synthesized by condensation reaction of N-(3-aminopropyl) pyrrole with salicylaldehyde and that N-(3-aminopropyl) pyrrole was prepared from reduced product of pyrrole with 3-chloropropionitrile by lithium aluminum hydride (LiAlH₄). The copolymers were synthesized with various molar ratios of pyrrole to N-(3-aminopropyl) pyrrole-salicylaldehyde (30:70, 40:60, and 50:50), via interfacial polymerization and also molar ratio of pyrrole to N-(3-aminopropyl) pyrrole-salicylaldehyde 30:70, via ultrasonic technique. The chemical structures of synthesized polymers and precursors were investigated by FT-IR and ¹H NMR. Thermal behavior of polymers was investigated by thermal gravimetric analysis. Morphology of synthesized polymers was studied by scanning electron microscopy (SEM), the conductivity of obtained polymers was investigated by four-probe conductivity measurement technique and the electroactivity behavior of synthesized polymers was investigated by cyclic voltammetry (CV) method. In proof, the ability of polymers in absorption of Ni(II) and Cu(II) was obtained from atomic absorption analysis. Secondly, the homopolymer of N-(3-aminopropyl) pyrrole and its copolymers with pyrrole were prepared by electrochemical polymerization CV in various molar ratios and the electroactivity behavior of synthesized polymers was investigated.

Keywords:

• Schiff base
• N-(3-aminopropyl) pyrrole
• salicylaldehyde
• copolymers
• conducting polymers