Rational design of glycidyl azide polymer-based triblock copolymers for high-performance energetic thermoplastic elastomers

Abstract

In aerospace applications, such as rockets and missiles, using thermoplastic elastomers (TPEs) in rocket propellants offers favorable properties that may allow them to replace traditional thermosetting elastomers. This study investigates the synthesis of energetic thermoplastic elastomers (ETPEs) with energetic characteristics, specifically focusing on synthesizing glycidyl azide polymer (GAP) ETPE and the effect of varying hard segment ratios on their physical properties. However, only the presence of azide side chains negatively impacts the mechanical properties of the ETPE and to address this issue, an ABA triblock copolymer synthesis approach is employed, utilizing poly (ε-caprolactone) (PCL) long linear chains to modify the original GAP, forming PCL-GAP-PCL ETPE. The introduction of PCL-GAP-PCL triblock copolymers significantly enhanced the mechanical properties of the resulting ETPE, providing substantial benefits for its use in specific environments. Furthermore, this study also investigates the effects of varying soft/hard segment ratios in the ETPE, suggesting that the subsequent incorporation of oxidizer fillers could yield favorable mechanical properties. Additionally, 2D infrared spectroscopy (2D-IR) was utilized to understand the effects of hydrogen bond formation and dissociation.