Thermal behavior of poly[3,3-bis(azidomethyl)oxetane] compositions with an energetic plasticizer: Calorimetric and optical studies

Publication date: Available online 19 March 2019Source: Journal of Molecular LiquidsAuthor(s): Konstantin V. Pochivalov, Tatyana N. Lebedeva, Anna N. Ilyasova, Andrey V. Basko, Yaroslav V. KudryavtsevAbstractAn experimental phase diagram for the high-energy system poly[3,3-bis(azidomethyl)oxetane] – three-component mixture of dinitrodiazaalkanes has been for the first time constructed in a broad temperature-concentration range using an original optical method and differential scanning calorimetry. The diagram belongs to the type semicrystalline polymer – thermodynamically good solvent, which is better than pure 2,4-dinitro-2,4-diazapentane studied earlier. The diagram contains two boundary curves, one describing full polymer amorphization and the other reflecting the solubility of the dinitrodiazaalkanes mixture in the amorphous polymer regions. The curves are shifted toward lower temperatures with an increase in the molar mass of the polymer. The domains on the phase diagram are classified using an original concept that treats semicrystalline polymers as microheterogeneous, internally stressed liquids with crystallites acting as crosslinks of the intermolecular network. The phase structure of the mixture at different points of the temperature-concentration field is illustrated with optical microphotographs. It is argued that calorimetry is not suitable as a standalone technique for investigating phase behavior of slowly crystallizing polymer systems.
Source: Journal of Molecular Liquids - Category: Molecular Biology Source Type: research