EVALUATION OF BRANCHED GLYCIDYL AZIDE POLYMER PURIFIED BY SOLVENT-EXTRACTION

Dimethyl sulfoxide (DMSO), a polar liquid of low volatility, was used as solvent in the synthesis of branched glycidyl azide polymer (GAP) w hich is a potential energetic binder for rocket propellants. Branched GAP product was purified by an extraction method using dichloromethane to create an organic phase and a mixture of methanol-brine (50:50 in weight) as the extracting solution. The extraction was carried out in four steps, leaving only less than 1% DMSO in the purified branched GA P. The DMSO concentration remaining in the organic phase was deduced f rom the H-1 NMR spectra taken after each extraction step. Finally, the physical performance of branched GAP was evaluated through the tensil e properties, the glass transition temperature, and the thermal degrad ation of the energetic polyurethanes obtained after curing branched GA P with different isocyanate compounds. The effect of residual DMSO in branched GAP on the tensile properties of polyurethanes was also inves tigated.