Publicado 6 números por año
ISSN Imprimir: 2150-766X
ISSN En Línea: 2150-7678
Indexed in
MIXING OF HYDROXYL-TERMINATED POLYBUTADIENE AND BORON
SINOPSIS
Mixing tests between boron and hydroxyl terminated polybutadiene ( HTPB ) often result in high viscous slurries. A research program about boron impurities and boron-HTPB mixtures was performed to explain this phenomenon. The viscosity of the mixture increases only if the shear Is sufficiently high. The evolution of the increase in viscosity stops when the stirring is discontinued. The gel permeation chromatography analysis of the boron-HTPB mixtures indicates the formation of very high molecular mass species, albeit the most of the polymer remains unmodified. The same result is obtained with boric anhydride or boric acid. The acidities were measured on a suspension of boron in a solvent by a potentiometric method. There are three acidities : a weak acidity ( pK =11 ), a middle ( pK between 7 and 9 ), and at times a strong ( pK = 4 ). The phenomenon described above is linked to the boron acidity. The results show that the HTPB hydroxy1 groups are linked to the boron surface with the acid impurities.
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Hu Xiu Li, Zhou Wei Liang, Xiao Le Qin, Jian Xiao Xia, Influence of Acidic Impurities on Rheological Properties of Boron/Agglomerated Boron and HTPB Slurry, Advanced Materials Research, 815, 2013. Crossref