Synergistic Enhancement Via Hydrogen-Bond Networks and Cage Strain Energy: Bicyclo[1.1.1]pentane-Based Energetic Plasticizers for Solid Propellants

Developing energetic plasticizers that integrate high energy density with excellent mechanical properties is a critical objective in solid propellant research. This work presents the design and synthesis of two bicyclo[1.1.1]pentane-based energetic compounds: bicyclo[1.1.1]pentane-1,3-diylbis(methylene) dinitrate (BCP-DMN) and bicyclo[1.1.1]pentane-1,3-diammonium nitrate (BCP-DAN·2NO 3 ). BCP-DMN shows favorable compatibility with HTPB. When incorporated into HTPB/TDI systems, BCP-DMN acts as an effective plasticizer, enhancing mechanical strength, migration resistance, and thermal stability through hydrogen bonding and microphase modulation. Compared with the conventional plasticizer di(2-ethylhexyl) adipate (DEHA), the BCP-DMN/HTPB/TDI product exhibits superior performance, with a migration loss of only 0.53% in ethanol, a tensile strength of 0.54 MPa, and an elongation at break of 154.2%. The system also achieves a higher cross-link density (3996 mol·m –3 ) and a more homogeneous soft–hard segment distribution, leading to synergistic structural reinforcement while maintaining high energy output. This study provides new design principles for advanced energetic plasticizers.