چكيده لاتين :
Aseries of new polyhydrazides were obtained by direct polycondensation of 4,4יdiphenyl
sulphone dicarboxylic acid with dihydrazides in ionic liquids (ILs) as a
new class of solvents which have interesting properties such as nonvolatility,
high ionic concentration, good thermal stability and non-flammability. Direct polycondensation
is successfully proceeded in ILs and triphenyl phosphite (condensing
agent), without any additional components, such as LiCI and pyridine. Therefore IL can
act as both solvent and catalyst. In this investigation high molecular weight polyhydrazides
have been synthesized and their properties such as solubility, and thermal
stability were studied. The resulting hydrazide containing polymers exhibited inherent
viscosities in 0.26-0.73 dUg range. All polymers were soluble in polar solvents such
as N-methyl pyrrolidone and dimethyl sulphoxide. The polyhydrazides had glass-transition
temperatures (Tg) between 165-210°C. They could be thermally converted into
the corresponding poly(1,3,4-oxadiazole)s approximately in the region of 210-330oC,
as evidenced by the TGA thermograms.
