Novel thermally stable poly(thiourea-amide-imide)s bearing CS moieties and pyridine units in the backbone: Synthesis and properties

Novel thermally stable and organosoluble poly(thiourea-amide-imide)s (PTAIs) were synthesized through the condensation of various diamines with a new kind of aromatic diacid chloride monomer containing pyridine units, 2-(3-(2-(3-(chlorocarbonyl)pyridin-2-yl)-1,3-dioxoisoindoline-5-carbonyl) thioureido) nicotinoyl chloride, CPDITNC. Spectroscopic and elemental analyses were carried out for the structure elucidation of synthesized monomers. Accordingly, the ensuing PTAIs were characterized by FTIR, ¹H and ¹³C NMR techniques along with crystallinity, organosolubility, inherent viscosity and GPC measurements. Consequently, polymers bearing phenyl thiourea and pyridine moieties in the backbone exhibited good organosolubility in a variety of highly polar solvents such as DMAc, DMF, DMSO and NMP. PTAIs encompassed η_inh of 1.24-1.46 dL/g and two of the polymers showed crystalline behavior. Moreover, GPC measurements of polymers revealed M_w around 33,000-50,000. Thermal stability of these polymers was ascertained via 10% weight loss temperatures in the range of 548-562 °C (inert atmosphere). Ultimately, these polymers own high glass-transition temperatures about 264-270 °C.