Aromatic-aliphatic phosphorous-containing copolyesters

A series of phosphorous-containing copolyesters was prepared by polycondensation of 2-(6-oxido-6H-dibenzo(c,e)(1,2)oxaphosphorin-6-yl)1,4-benzenediol, 1, or of an equimolecularamount of 1 and different aliphatic diols 2, such as: ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol and 1,12-dodecanediol with an aromatic diacid chloride containing two preformed ester groups 3, namely terephthaloyl-bis-(4-oxybenzoyl-chloride).The copolyesters exhibited good thermal stability having the decomposition temperature above 360 degrees C and char yield at 700 degrees C in the range of 8.4-41%. The glass transition temperature was in the range of 83-160 degrees C The polymers exhibited thermotropic liquid crystalline behaviour.