Preparation and characterization of schiff base polythioamides derived from [4,4'-methylenebis (cinnamaldehyde)] by Willgerodt-Kindler reaction

Five new polythioamides were prepared by polycondensation of a mixture of sulphur and various diamines with a dicarbonyl compound [4,4'- methylenebis(cinnamaldehyde)] (MBC). The used diamino compounds were ethylenediamine, 1,3-propylenediamine, meso-stilbenediamine, semicarbazide, and thiosemicarbazide. The polythioamides formed were characterized by elemental microanalysis, FTIR, UV, Vis, and 1H NMR spectroscopies, thermal analysis and viscosity measurement. All the polythioamides indicated a characterized band within 1230-1260 cm-1 due to νC=S vibrations. The synthesized polythioamides indicated better thermal stability up to 600C. The dialdehyde (MBC) and polythioamides were soluble in number of organic solvents including tetrahydrofuran, dimethyl formamide, dimethyl acetamide, and dimethyl sulphoxide. The intrinsic viscosities of these polythioamide ranged within 0.393-0.5201 dL/g as compared to 0.174-0.249 dL/g for dialdehyde (MBC) in THF.