Toughening modification of cellulose acetate butyrate and using for CL-20-based polymer bonded explosives

Abstract

CAB is a binder commonly utilized in CL-20-based mixed explosives. Based on the requirements of CL-20-based polymer bonded explosives in formability, safety, and detonation energy, we explored a high-toughness and low dosage CAB binder system. CAB was subjected to different toughening modifications and the effects of the modified CAB binders on the bonding and coating of CL-20 crystals, as well as the formability, safety, and mechanical properties of CL-20-based polymer bonded explosive molding powder (MP) were evaluated. The changes in glass transition temperature (T_g) and mechanical properties of the modified binders were investigated using the molecular dynamics simulation at first. A series of modified binders with different molecular weights were then synthesized and characterized by FTIR, ¹H NMR, ¹³C NMR and SEC. The T_g and cross-sectional morphologies of the binder membranes were determined by DSC and SEM. The tensile properties of the binder membranes with different molecular weights and their mixtures with the plasticizer were evaluated at different temperature. With the optimized modified binder, CL-20/CAB and CL-20/CAB-g-PCL-3 MPs with the same plasticizer ratio and Cl-20/CAB-g-PCL-3 MP with a lower plasticizer ratio and higher CL-20 content were prepared and evaluated for the bonding and coating effects, crystal form, mechanical sensitivity and specific heat capacity (C_p) by SEM, XRD, sensitivity testing and DSC, respectively. Their compressive strengths and splitting tensile strengths were measured at different temperature using a universal testing machine. Our work has provided a high-toughness and low-dosage binder system for CL-20-based MPs and offers a novel strategy to improve the formability, safety, and energy of CL-20 based polymer bonded explosives.