The general polyol methods used for synthesizing copper nanoparticles (CuNPs) usually require high temperatures to ignite the reduction reaction, which leads to the difficulty of controlling the particle size. Herein, a new polyol method for the size-controllable synthesis of CuNPs at low temperatures by adopting high-pressure hydrogen as the reductant is verified. It is proven that hydrogen is capable to reductively produce CuNPs at temperatures as low as 120 °C. The size of the CuNPs can be controlled between 19.29 nm and 140.46 nm by adjusting the hydrogen pressure, the reaction temperature, and duration. An empirical relationship between temperature and particle size is proposed. This work verifies a low-temperature strategy to synthesize nanoparticles with good size-controllability.
SongYuChen Ma,Tao Liu,DeQi Wang,YinHui Li,WenJing Shi,FengSheng Li,Jie Liu
To address the quality issues arising from the uncontrollable morphological grain size in the preparation of CL-20/HMX cocrystals, a novel method for producing high-quality cocrystals with well-defined morphological grain sizes has been developed. The cocrystallization process was conducted using the solvent/nonsolvent method, wherein the mixing efficiency and solution supersaturation were precisely controlled through systematic optimization of key parameters, including solvent composition, solvent/nonsolvent ratio, reaction temperature, and stirring rate. Through systematic optimization of experimental parameters, three distinct rhombohedral CL-20/HMX cocrystal samples with uniform particle size distributions and well-defined morphologies were successfully prepared, exhibiting characteristic D50 values of 20, 63, and 130 μm. Comprehensive characterization revealed that SEM analysis demonstrated the cocrystals possess smooth surfaces and regular geometric shapes. Combined XRD and micro-CT analyses confirmed the high crystallinity of the cocrystals, particularly noting the reduced internal defects and superior crystal perfection in larger-grained samples. DSC measurements indicated enhanced thermal stability in cocrystals with larger particle sizes. Furthermore, sensitivity testing showed larger-grained cocrystals are less sensitive than smaller-grained ones, which can be attributed to the more compact internal structure of the crystals.
危险品化学品经营许可证（带存储）