SIZE-EXCLUSION AND ADSORPTION COLUMN CHROMATOGRAPHIC STUDIES ON FUNCTIONALITY DISTRIBUTION OF HTPB

Adsorption column chromatography and size exclusion chromatography hav e been used to determine the functionality distribution of hydroxyl te rminated polybutadiene (HTPB), a modern solid propellant binder. The r esin after conversion to 3,5-dinitrobenzoyl ester was separated into v arious fractions on a silica column. The fractions were analysed using a dual detector (UV and differential refractive index) analytical gel permeation chromatograph. The functionality of each fraction calculat ed from the chromatogram showed a continuous increase with increase in the molecular weight. The adsorption chromatography method is unable to fractionate the polymer into fractions with specific functionality. All the fractions have molecules ranging from monofunctional to multi functional ones and therefore the apportionment method followed in the conventional adsorption chromatography method yields conflicting resu lts.