| Abstract: | Pyromellitic dianhydride (PMDA) was condensed with oxalic- and malonic-acid dihydrazides. The optimum experimental conditions have been worked out and the viscosity values were determined. The polyhydrazid carbonic acids so obtained were converted to the corresponding polymidimidcompounds by means of thermal cyclisations. Similar polycondensations were carried out with 3,3′-disulfo-4,4′-dicarboxy-diphenylsulfondianhydride and different hydrazides. The same dianhydride was also used for the synthesis of the carbodihydrazide. Further a sulfondihydrazide was prepared from 4,4′-ditolysulfon-3,3′-disulfochlorid. |
