Azide Polyether with a Highly Flexible Main Chain as Energetic Materials AITranslate

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DOI：https://doi.org/10.1021/acsapm.3c00241

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Poly(3-azidemethyl-3-methyl oxetane) (PAMMO) is an azide-containing polymer that has been widely studied, but some problems, such as its complex synthetic route, high preparation costs, and low elongation, restrict its practical applications. Therefore, it is of great significance to design and synthesize an azide polyether that is low in cost, highly flexible, and has a comparable energy level to that of PAMMO. In this paper, we synthesized an azide polyether, poly(2-azidemethyl-1,3-dioxolane) (PADOL), through a simple two-step reaction. The first step was a cationic ring-opening polymerization using 2-chloromethyl-1,3-dioxane (CDOL) as a monomer, and the second step was an azidation reaction. The synthesized PADOL had a controlled molar mass and low dispersity, and the degree of functionality of the terminal hydroxyl group was close to the theoretical value. In addition, 3,3-bisazidemethyl oxetane-2-azidemethyl-1,3-dioxolane random copolymers (PBAMO-ADOLs) were also synthesized using CDOL and 3,3-bischloromethyl oxetane (BCMO) as monomers in the same two-step reaction scheme discussed above. The copolymerization kinetics showed that the reactivity ratios of CDOL and BCMO were similar, and the copolymerization process was close to an ideal copolymerization. When the ADOL content in the PBAMO-ADOL copolymer was up to 27%, the crystallinity of the BAMO chain segment was effectively reduced, and an amorphous azide-containing polymer was obtained. Thanks to the higher oxygen content and short side chain length, PADOL exhibited a lower glass transition temperature and viscosity than PAMMO, and the prepared energetic thermoplastic elastomer (ETPE) had a higher fracture elongation. Moreover, the higher oxygen content in PADOL promoted the decomposition of the polymer backbone, resulting in a higher absolute value of the heat of combustion and lower residual carbon content.