TY - JOUR
T1 - Characterization of nitro-substituted polybenzimidazole synthesized by the reaction with nitric acid
AU - Choi, Jin Hyun
AU - Lyoo, Won Seok
AU - Ha, Wan Shik
AU - Rossbach, Volker
PY - 1995
Y1 - 1995
N2 - Nitro-substituted poly [2,2’ -(m-phenylene)-5,5‘-bibenzimidazole]s (PBIs) were synthesized by the reaction of PBI with nitric acid in sulfuric acid under various conditions. The number of nitro groups substituted on the aromatic ring of PBI per polymeric unit varied from 1.44 to 3.55 according to the reaction conditions. An increase in reaction temperature and concentration of the nitric acid increased the degree of substitution. The inherent viscosity of the substituted polymer increased as the reaction temperature decreased. When the reaction temperature was 30°C, the inherent viscosity of the polymer increased as the concentration of nitric acid increased. The nitro-substituted PBI exhibited polyelectrolyte behavior in formic acid. The nitro groups substituted on PBI were dissociated when the polymer was heated to 450°C, displaying exothermic behavior, and the decomposition of polymer was proportional to its nitro group content. All nitro-substituted PBIs showed better solubilities in polar aprotic and acidic solvents, such as dimethylacetamide, dimethylsulfoxide, dimethylformamide, N-methylpyrrolidone, formic acid, sulfuric acid, and trifluoromethanesulfonic acid.
AB - Nitro-substituted poly [2,2’ -(m-phenylene)-5,5‘-bibenzimidazole]s (PBIs) were synthesized by the reaction of PBI with nitric acid in sulfuric acid under various conditions. The number of nitro groups substituted on the aromatic ring of PBI per polymeric unit varied from 1.44 to 3.55 according to the reaction conditions. An increase in reaction temperature and concentration of the nitric acid increased the degree of substitution. The inherent viscosity of the substituted polymer increased as the reaction temperature decreased. When the reaction temperature was 30°C, the inherent viscosity of the polymer increased as the concentration of nitric acid increased. The nitro-substituted PBI exhibited polyelectrolyte behavior in formic acid. The nitro groups substituted on PBI were dissociated when the polymer was heated to 450°C, displaying exothermic behavior, and the decomposition of polymer was proportional to its nitro group content. All nitro-substituted PBIs showed better solubilities in polar aprotic and acidic solvents, such as dimethylacetamide, dimethylsulfoxide, dimethylformamide, N-methylpyrrolidone, formic acid, sulfuric acid, and trifluoromethanesulfonic acid.
UR - http://www.scopus.com/inward/record.url?scp=0004499795&partnerID=8YFLogxK
U2 - 10.1080/10601329508009367
DO - 10.1080/10601329508009367
M3 - Article
AN - SCOPUS:0004499795
SN - 1060-1325
VL - 32
SP - 1875
EP - 1891
JO - Journal of Macromolecular Science - Pure and Applied Chemistry
JF - Journal of Macromolecular Science - Pure and Applied Chemistry
IS - 11
ER -