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Important engineering aspects related to the production of polyoxadiazole (POD), from the polycondensation of 4'4'-diphenyl-ether-dicarboxylic acid (DPE), and hydrazine sulphate (HS), in poly(phosphoric acid) (PPA), such as reproducibility of final polymer properties and sensitivity to initial feed charge, were investigated. When the reaction variables are not tightly controlled, large variations...
A new technique based on nuclear magnetic resonance (NMR) is developed in this paper to determine quantitatively the hydrazide content in poly(oxadiazole-hydrazide) copolymers. Two-dimensional 1 H– 13 C shift correlation and 1 H NMR spectra of poly(4,4′-diphenylether-1,3,4-oxadiazole-hydrazide) copolymers with different hydrazide contents were performed to characterize these...
Aiming to produce flexible films of poly(4,4'-diphenylether-1,3,4-oxadiazole), POD-DPE, the synthesis of POD-DPE through thermal cyclodehydration of polyhydrazide in solutions of poly(phosphoric acid), PPA, and in film form is studied here. It was observed that POD-DPE polymer samples obtained when the cyclodehydration of polyhydrazide is performed in solutions of PPA are insoluble in the solvents...
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