Dynamic mechanical analysis and molecular structure analysis of an energetic thermoplastic elastomer

This study investigates the dynamic mechanical properties and molecular relaxation mechanisms of glycidyl azide polymer-based energetic thermoplastic elastomer (GAP-ETPE) through dynamic mechanical analysis (DMA). This work quantitatively revealed the relationship between the molecular motion pattern and the macroscopic performance of GAP-ETPE. Frequency-dependent DMA tests demonstrated that increased loading frequency shifts storage modulus ( E ′) curves toward higher temperatures, with glass transition temperature ( T _g, defined by E ″ peak) ranging from −36.25 °C to −32.71 °C. Exponentially Modified Gaussian (EMG) deconvolution identified three molecular motional units: Peak 1 (soft-segment relaxation), Peak 2 (imperfect hard-segment domains), and Peak 3 (ordered hard-segment microcrystals). Frequency increases drove a 20.6 % reduction in Peak1 contribution while elevating Peak 2 and Peak 3 by 16.79 % and 3.75 %, respectively, indicating hard-segment reorganization under dynamic loads. A master curve for E ′ was established via time-temperature superposition (TTS), enabling prediction of viscoelastic behavior across extended frequencies (10⁻³–10³ Hz) with an Arrhenius-derived activation energy of 291.11 kJ·mol⁻¹. This work provides important insights into the dynamic mechanical properties of GAP-ETPE under complex use conditions, supporting the design of adhesives for high-energy composites.