Many of the physical and functional properties of RDX and HMX explosives are related to the crystalline structure of these materials. Crystalline defects affect the quality of the explosives. Therefore, in order to en...Many of the physical and functional properties of RDX and HMX explosives are related to the crystalline structure of these materials. Crystalline defects affect the quality of the explosives. Therefore, in order to enhance the quality of these materials, it is necessary to form crystals with the lowest defects. In this research, we report the optimization of recrystallization process of RDX and HMX by statistical techniques. The solvent/anti-solvent procedure was used for recrystallization of HMX and RDX particles. The four parameters of i) ratio of anti-solvent to solvent, ii) ratio of solute to solvent, iii) aging time, and iv)cooling rate of mixture, were optimized by Taguchi analysis design. Taguchi L16 orthogonal array was used with sixteen rows corresponding to the number of tests in four columns at four levels. The apparent density of recrystallized of RDX and HMX particles was considered as the quality characteristic with the concept of "the larger-the-better". The obtained graphs showed that the studied parameters were optimized in ratio 1:1 for anti-solvent to solvent, ratio 0.1 g,m L^(-1) for solute to solvent, aging time of 2 h and cooling rate of 1℃,min^(-1). Also, the correlation between the investigated parameters and apparent density of crystals were studied by multiple linear regressions(MLR) method for obtaining a model of prediction of apparent density. The P-values were indicated that in confidence level of 95%, the null hypothesis is rejected and a meaningful addition is observed in the proposed model.展开更多
选用价廉无毒的碳酸氢钠(NaHCO_3)作为发泡剂,利用反溶剂重结晶法进行细化,成功地制备出超细NaHCO_3粒子。最佳制备条件为:使用10%质量分数的NaHCO_3,蒸馏水与无水乙醇体积比1∶14,搅拌速度1100 r/min,制备温度-5℃,入料速度1 m L/min...选用价廉无毒的碳酸氢钠(NaHCO_3)作为发泡剂,利用反溶剂重结晶法进行细化,成功地制备出超细NaHCO_3粒子。最佳制备条件为:使用10%质量分数的NaHCO_3,蒸馏水与无水乙醇体积比1∶14,搅拌速度1100 r/min,制备温度-5℃,入料速度1 m L/min。纳米粒度分析仪测试表明NaHCO_3平均尺寸为143.2 nm,尺寸分布非常窄。将超细NaHCO_3添加到聚丙烯(PP)中进行微孔发泡,使用扫描电镜观察并使用Nano Measurer分析泡孔尺寸,表明当NaHCO_3用量为4.5 phr时,其泡孔平均尺寸低至0.47μm,泡孔尺寸标准方差仅为0.16μm,低于任何文献报道值。力学性能较优,其中拉伸强度下降了9.6%,而冲击强度提高了47.8%,弯曲强度提高了20.2%。这种使用普通注塑机获得高质量低成本的微孔发泡材料,对微孔材料的制备和应用有一定的意义。展开更多
文摘Many of the physical and functional properties of RDX and HMX explosives are related to the crystalline structure of these materials. Crystalline defects affect the quality of the explosives. Therefore, in order to enhance the quality of these materials, it is necessary to form crystals with the lowest defects. In this research, we report the optimization of recrystallization process of RDX and HMX by statistical techniques. The solvent/anti-solvent procedure was used for recrystallization of HMX and RDX particles. The four parameters of i) ratio of anti-solvent to solvent, ii) ratio of solute to solvent, iii) aging time, and iv)cooling rate of mixture, were optimized by Taguchi analysis design. Taguchi L16 orthogonal array was used with sixteen rows corresponding to the number of tests in four columns at four levels. The apparent density of recrystallized of RDX and HMX particles was considered as the quality characteristic with the concept of "the larger-the-better". The obtained graphs showed that the studied parameters were optimized in ratio 1:1 for anti-solvent to solvent, ratio 0.1 g,m L^(-1) for solute to solvent, aging time of 2 h and cooling rate of 1℃,min^(-1). Also, the correlation between the investigated parameters and apparent density of crystals were studied by multiple linear regressions(MLR) method for obtaining a model of prediction of apparent density. The P-values were indicated that in confidence level of 95%, the null hypothesis is rejected and a meaningful addition is observed in the proposed model.
