Thermally stable polymers containing 1,3,4-oxadiazole units have been synthesized through Huisgen reaction of the aromatic/aliphatic bis-tetrazole compounds with the aromatic/aliphatic bis-acid chlorides in pyridine a...Thermally stable polymers containing 1,3,4-oxadiazole units have been synthesized through Huisgen reaction of the aromatic/aliphatic bis-tetrazole compounds with the aromatic/aliphatic bis-acid chlorides in pyridine as solvent.The obtained polymers are insoluble or slightly soluble even in polar aprotic solvents such as DMSO and DMF.Relatively high inherent viscosity values（0.61-1.33 dL/g,in 0.125%H_2SO_4 at 25℃） were observed for these compounds.Thermal analyses of the polymers using DSC and TGA techniques showed that the polymers have improved thermal stabilities.The glass transition temperature has not been observed in the fully aromatic polymers,but the polymers obtained from 5-[6-（1H-tetrazol -5-yl）hexyl]-lH-tetrazole（Ⅳ） showed very clear T_g.A model reaction was also investigated and the resulting bis-1,3,4-oxadiazole compound was characterized by conventional spectroscopy methods.展开更多
In this work, the syntheses of new thermally stable poly（amide-imide）s with pendant 2-pyridyl-l,3,4-oxadiazole units in n-butyl methyl imidazolium bromide as reaction media have been reported. A new dicarboxylic aci...In this work, the syntheses of new thermally stable poly（amide-imide）s with pendant 2-pyridyl-l,3,4-oxadiazole units in n-butyl methyl imidazolium bromide as reaction media have been reported. A new dicarboxylic acid has been derived from the reaction of diamine, 2-（5-（3,5-diaminophenyl）-1,3,4-oxadiazole-2-yl）pyridine （POBD）, and trimellitic acid anhydride. Polymers were prepared from the reaction of the diimide-diacid （DIDA） and different aromatic diamines in butyl methyl imidazolium bromide, [bmim] [Br], in the presence of triphenyl phosphite （TPP） as condensing agent without needing any extra components. The prepared poly（amide-imide）s were characterized by FTIR, elemental analysis, and through the synthesis of a model compound. The prepared polymers were soluble in polar and aprotic solvents, such as DMF, DMSO, NMP and DMAc. The inherent viscosity of the polymer solutions was in the range of 0.52-1.33 dL/g measured in concentrated H2SO4 at a concentration of 0.125 g/dL at （25 ± 0.5）℃. The results are compared with the results obtained from common direct polycondensation with NMP as solvent. Polymers obtained in ionic liquid showed higher inherent viscosity than that of polymers obtained via classical method in NMP. Thermal properties of the polymers were studied with DSC and TGA methods.展开更多
基金financially supported by the Research Council of the University of Mohaghegh Ardabili(Iran)
文摘Thermally stable polymers containing 1,3,4-oxadiazole units have been synthesized through Huisgen reaction of the aromatic/aliphatic bis-tetrazole compounds with the aromatic/aliphatic bis-acid chlorides in pyridine as solvent.The obtained polymers are insoluble or slightly soluble even in polar aprotic solvents such as DMSO and DMF.Relatively high inherent viscosity values（0.61-1.33 dL/g,in 0.125%H_2SO_4 at 25℃） were observed for these compounds.Thermal analyses of the polymers using DSC and TGA techniques showed that the polymers have improved thermal stabilities.The glass transition temperature has not been observed in the fully aromatic polymers,but the polymers obtained from 5-[6-（1H-tetrazol -5-yl）hexyl]-lH-tetrazole（Ⅳ） showed very clear T_g.A model reaction was also investigated and the resulting bis-1,3,4-oxadiazole compound was characterized by conventional spectroscopy methods.
基金financially supported by the Research Council of The University of Mohaghegh Ardabili(Iran)
文摘In this work, the syntheses of new thermally stable poly（amide-imide）s with pendant 2-pyridyl-l,3,4-oxadiazole units in n-butyl methyl imidazolium bromide as reaction media have been reported. A new dicarboxylic acid has been derived from the reaction of diamine, 2-（5-（3,5-diaminophenyl）-1,3,4-oxadiazole-2-yl）pyridine （POBD）, and trimellitic acid anhydride. Polymers were prepared from the reaction of the diimide-diacid （DIDA） and different aromatic diamines in butyl methyl imidazolium bromide, [bmim] [Br], in the presence of triphenyl phosphite （TPP） as condensing agent without needing any extra components. The prepared poly（amide-imide）s were characterized by FTIR, elemental analysis, and through the synthesis of a model compound. The prepared polymers were soluble in polar and aprotic solvents, such as DMF, DMSO, NMP and DMAc. The inherent viscosity of the polymer solutions was in the range of 0.52-1.33 dL/g measured in concentrated H2SO4 at a concentration of 0.125 g/dL at （25 ± 0.5）℃. The results are compared with the results obtained from common direct polycondensation with NMP as solvent. Polymers obtained in ionic liquid showed higher inherent viscosity than that of polymers obtained via classical method in NMP. Thermal properties of the polymers were studied with DSC and TGA methods.
