Synthesis and properties of some phosphorus-containing polyesters

Phosphorus-containing polyesters were prepared by polycondensation of 2-(6-oxido-6H-dibenz (c,e) < 1,2>oxaphosphorin-6-yl)-1,4-benzenediol with different aromatic dicarboxylic acids using a SOCl2/pyridine condensing agent. The polymers were soluble in polar organic solvents such as N-methylpyrrolidone, N,N-dimethylformamide, tetrahydrofuran and chloroform. They showed high thermal stability having a decomposition temperature above 360 degrees C and char yield at 700 degrees C in the range of 19-32%. The glass transition temperature was in the range of 180-194 degrees C. Solutions of the polymers in N,N-dimethylformamide showed fluorescence having maximum emission wavelength around 362 nm. One of the polymers exhibited thermotropic liquid crystalline behavior.