Synthesis and Characterization of Low Molecular Weight Azido Polymers as High Energetic Plasticizers

Abstract

ABSTRACT The present work describes a convenient process for the preparation of low molecular weight hydroxyl-terminated glycidyl azide polymers. The facile route involves the formation of glycidyl azide polymer in a single step. The polymerization of epichlorohydrin was carried out in dipolar aprotic solvent N,N1-dimethylformamide (DMF) medium using diols as initiators in the presence of sodium azide. Various low molecular weight diols such as ethylene glycol (EG), propylene glycol (PG), diethylene glycol (DEG), 2-methylpentane-2,4-diol (MPD), and resorcinol (RS) are employed as initiators in the present investigation. The effect of initiating diols on the polymer formation was confirmed by gel permeation chromatography (GPC) and vapor pressure osmometry (VPO). The GPC analysis indicates that the glycidyl azide polymers (GAPs) contain different-sized oligomers, due, to the multimodal molecular weight distribution. The GAPs obtained in all the polymerizations by using different diols have a maximum of five to seven glycidyl azide repeating units. Further, the effect of diol on the GAP decomposition was investigated, and it was found that the GAPs obtained by using different diol units have a thermal decomposition pattern similar to that of glycidyl azide polymer. Since the glycidyl azide polymers have low molecular weights, their glass transition temperatures, are lower, betweens − 70° and − 72°C, due to variation in the structure of the polymers. Structural analysis of the GAPs using spectral methods revealed that the initiating diol units are present in the polyether backbone of GAPs. Nitrogen content and solubility tests were also performed.