Micro-sized ZIF-67 crystals were prepared and used as the reinforcing material to design novel paraffin-based composite phase change materials with a polymethyl methacrylate shell.

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The composite modified double base (CMDB) propellants containing 2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazatetracyclo[5.5.0.05,9.03,11] dodecane (CL‐20), 1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocane (HMX) or CL‐20/HMX cocrystal were prepared by the solventless extrusion formation technique. The performances of CMDB propellants were evaluated by means of stability, sensitivity, combustion and mechanical experiments. Raman spectra analysis indicated the stability of CL‐20/HMX cocrystal is partially destroyed in the rolling process under 90 °C, 10 MPa. Methyl violet tests revealed that the colored time of CMDB propellants containing CL‐20/HMX cocrystal, CL‐20 or HMX are 77, 60, and 75 min, respectively. Burning rate tests shown that the burning rates of CMDB propellants containing CL‐20/HMX cocrystal, CL‐20 or HMX in the pressure range of 8 to 18 MPa, increased 1.82, 4.67, and 4.67 mm/s, with the pressure exponents 0.095, 0.306, and 0.346, respectively. Mechanical property tests revealed that the mechanical properties of CMDB propellant containing CL‐20/HMX cocrystal are inconsistent, but the tensile strength has improved compare with CMDB propellant containing CL‐20. These results suggest that CL‐20/HMX cocrystal is a potential material to solve the application problem of the safety performance and stability of the propellants containing CL‐20.

Adding nano-Fe2O3 to a CL-20/HMX cocrystal affects its thermal decomposition peak temperature and products.

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This paper provides a comprehensive understanding of the amplitude- and frequency-dependent characteristics of rubber springs. The dynamic nonlinear inelasticity of rubber is a key academic problem for continuum mechanics and a bottleneck problem for the practical use of rubber structures. Despite intensive efforts witnessed in industrial applications, it still demands an unambiguous constitutive model for dynamic nonlinear inelasticity, which is known as the Payne effect. To this end, three types of rubber springs (shear-type (ST), compression-type (CT) and shear-compression-combination-type (SCCT)) were tested with amplitude and frequency sweeps in different conditions. We investigated and present changes in dynamic stiffness and loss factor with amplitude, frequency and the hysteresis loops of different rubber springs. We also propose a hypothesis and research strategy to study a constitutive model involving multiple factors of hyperelasticity, the Mullins effect, viscoelasticity and the Payne effect, which we hope will provide new ideas for the establishment of a constitutive equation.