Poly(Azomethine Sulfones) with Thermotropic Liquid Crystalline Behavior

Abstract

Abstract New poly(azomethine sulfones) with linear structures containing sulfonyl bis(4-phenoxyphenylene) and oxo bis(benzylideneaniline) or methylene bis(benzylideneaniline) units were prepared in the conventional literature manner by condensing the dialdehyde sulfone monomer (V) with diamines such as 4,4′-oxydianiline (IIIa) and 4,4′-methylenedianiline (IIIb), or by condensing an azomethine biphenol (IX) with 4,4′-sulfonyldichlorobenzene (II). Three model compounds which reproduced the above structures were also synthesized. The resulting polymers were confirmed by IR, 1H-NMR, and elemental analysis, and were characterized by inherent viscosities, thermogravimetric analysis (TGA), and x-ray diffraction. The thermotropic liquid crystalline (TLC) behavior was studied using polarization light microscopy (PLM), thermooptical analysis (TOA), and DSC. A nematic texture was observed only for 4,4′-oxydianiline-units-based polymers. The reaction of polymer VIIIb containing – CH2– links between the mesogens with the model compound IX led to polymer X which exhibited TLC behavior.