采用半制备型凝胶渗透色谱(GPC)仪进行聚叠氮缩水甘油醚基含能热塑性弹性体(GETPE)窄分布聚合物自动分级制备方法的试验,确定了色谱制备最优条件:色谱柱为PLgel MIXED-D(300 mm × 25 mm,10.0 μm),流动相为四氢呋喃,流速为6.0 mL/min,自动进样器进样量为900 μL,进样质量浓度为40mg/mL,柱温为40℃,三通阀经过检测器和馏分收集器的体积流量比为1∶5.严格控制制备色谱条件,采用馏分收集器进行多次收集、混批、合并,通过旋转蒸发的方式进行样品浓缩,获得质量为20g,技术指标满足相对分子质量20 000±2 000、分子量分布＜2.0的GETPE窄分布样品.该方法具有控制精准、自动化程度高的优点.

For the optimization and scale-up of the dilution crystallization process of 2,6-dipicrylamino-3,5-dinitropyridine(PYX),the dilution crystallization kinetics of PYX was studied in the crystallization system with DMF as the solvent and H2O as the anti-solvent.Firstly,the solubility curves of PYX in DMF pure solvent and DMF-H2O binary solvent were measured by with laser dynamic method,by which the corresponding solubility models were established.And then,the crystal growth type of PYX was determined.The crystal growth and nucleation rates of PYX in the dilution crystallization process were measured,and the corresponding crystallization kinetics models were established.On this basis,the effect factors and laws of the crystalliza-tion kinetics of PYX were analyzed.The results show that the solubility of PYX in DMF pure solvent and DMF-H2O binary sol-vent with different volume ratios increases with increasing temperature,and decreases with increasing H2O content.The solu-bility of PYX in different solvents was fitted by Apelblat model,where the correlation coefficients of the fitting results are all greater than 0.99.The crystal growth type of PYX is particle size independent growth.The crystal growth and nucleation acti-vation energy of PYX are 8.33 × 103J/mol and 1.01 × 104J/mol,respectively.The index of supersaturation ratio to crystal growth rate is 6.73.The stirring strength,supersaturation ratio and suspension density to crystal nucleation rate are 0.27,7.16 and 0.14,respectively.The crystal growth and nucleation rates of PYX increase along with the increase of temperature and supersaturation ratio.Also,the increase of temperature or supersaturation ratio is more conducive to the crystal nucleation of PYX.Compared with the supersaturation ratio,the stirring intensity and suspension density have less effect on the crystal nu-cleation rate of PYX,and increasing the stirring intensity or suspension density is detrimental to the crystal growth of PYX.

In order to optimize the crystal formability and improve the application performance of PYX, the solvent-antisolvent method was used to recrystallize PYX, and the better recrystallization system was determined. The influencing factors and laws of PYX crystal morphology and particle size distribution were explored, and the recrystallization conditions were optimized. The crystal structure, thermal property and mechanical sensitivity of PYX before and after recrystallization were analyzed. The results show that using 1-methyl-2-pyrrolidone（NMP） as solvent and water as antisolvent, the regular cubic crystals can be prepared under the conditions: crystallization temperature is 65℃, stirring rate is 300r/min, crystallization concentration is 20mg/mL, and antisolvent adding rate is 2mL/min. The crystal length-diameter ratio is significantly smaller than those before recrystallization, and has no obvious defects, and with good surface smoothness. Recrystallization can reduce the average particle size and optimize the uniformity of particle size distribution of PYX. The particle size(d 50 ) and the particle size span（S） of PYX after recrystallization is reduced by 49.51μm and 0.27 compared with that before recrystallization, respectively. The crystal structure of PYX does not change after recrystallization. Recrystallization can improve the thermal stability of PYX and reduce the mechanical sensitivity of PYX. After recrystallization, the thermal decomposition peak temperature and thermal explosion critical temperature of PYX are increased by 5.0℃ and 6.6℃, and the impact sensitivity and friction sensitivity are decreased by 20% and 16%, respectively.

分别采用降温法和溶剂-反溶剂法对2,6-二苦氨基-3,5-二硝基吡啶(PYX)进行了重结晶研究.表征了不同重结晶方法所得PYX晶体的形貌和粒径,测定了重结晶前、后的晶体纯度,研究了重结晶对晶体热性能和机械感度的影响.结果表明:采用降温法在DMSO中得到的多为小颗粒团聚形成的不规则块状PYX晶体;采用溶剂-反溶剂法在DMF或DMSO中得到的多为片状PYX晶体,在DMSO/DMF混合溶剂中得到的多为规则的多边形块状PYX晶体.相比较而言,多边形块状PYX晶体的表面光滑度良好,粒径跨度最小,纯度最高,热稳定性较优,且兼具最低的撞击感度和摩擦感度,其热分解峰温和热爆炸临界温度较重结晶前分别提高了8.99℃和9.11℃,撞击感度和摩擦感度较重结晶前分别降低了16％和12％.

为了重塑2,6-二苦氨基-3,5-二硝基吡啶(PYX)的晶体形貌,改善PYX的晶体品质,采用激光动态法测定了PYX在二甲亚砜(DMSO)中的溶解度,建立了溶解度模型,估算了溶解过程的热力学参数;测定了不同条件下PYX在DMSO中的介稳区宽度,揭示了介稳区宽度的影响因素及规律,计算了成核级数;在此基础上采用降温法对PYX进行重结晶,对比分析了重结晶前后的晶体形貌和热性能.结果表明,PYX在DMSO中的溶解度随温度的升高而增大,Apelblat模型对溶解度的拟合结果较好,更适合预测溶解度;介稳区宽度随降温速率的增大而增大,随饱和浓度和搅拌速率的增大而减小,结合介稳区变化规律得到适宜的结晶条件为:饱和浓度(摩尔分数)0.016～0.022、降温速率1～2℃/min、搅拌速率250～500 r/min;当饱和浓度从0.0148增至0.0224时,受降温速率影响的成核级数(m)由3.7010增至4.7461,受搅拌速率影响的成核级数(n)由0.3601增至0.6284.PYX在DMSO中经降温重结晶能够得到表面光滑度良好、无明显缺陷的块状晶体,重结晶后PYX的DSC热分解峰温提高了 11.9℃,热爆炸临界温度提高了 9.8℃,说明通过重结晶能够优化PYX的热稳定性.

提出了一种RDX非自身标样定量分析方法,通过气相色谱-原子发射检测器(GC-AED)实现了无RDX标准物质情况下对RDX的高灵敏度定量检测,有效解决了无RDX标准物质带来的定量检测难题.结果 表明:最佳定量元素谱线为C(193 nm),最佳外标物为DBP.以DBP为外标物,通过C(193 nm)定量测定RDX的线性范围为0.07～ 2.02 mg/mL.以3倍信噪比计算检测限,得到RDX的方法检测限为0.06 μg/mL.RDX在线性范围内高、中、低浓度的加标回收率分别为97.45％、101.37％和87.71％,相对标准偏差分别为0.33％、0.81％和0.36％.该方法具有较好的准确度和精密度,在无RDX标准物质的情况下亦能对RDX进行定量分析.

气相色谱–原子发射检测器(GC–AED)是一种特色鲜明的联用技术,兼具气相色谱(GC)的分离能力和原子发射检测器(AED)的元素检测能力,能够进行多元素检测的同时还具有元素的等摩尔效应.介绍了GC–AED的原理、组成和特点,重点综述了GC–AED在元素选择性检测、组分定量分析及元素比例式推断共三个方面的应用概况,并对其应用前景进行了展望.

采用气相色谱-原子发射光谱对TNT进行定量测定,建立了一种非含能非自身标样定量测定方法.以二号中定剂为外标物,通过二号中定剂的C元素标准曲线定量TNT中的C元素.结果 表明:用二号中定剂作外标物定量TNT的C元素线性范围是22.43 ～637.50μg/mL,相关系数(r)为0.999 9.以3倍信噪比计算检测限,得到TNT的C元素方法检测限为0.015 μg/mL.TNT在高、中、低浓度下的回收率为94.6％～101.3％,相对标准偏差为0.3％～0.7％.该方法具有较好的准确度和精密度,在自身标准物质缺乏的情况下能够对TNT进行准确定量.

为了在标准物质缺乏的情况下能够准确定量3,4-二硝基呋咱基氧化呋咱(DNTF),采用气相色谱-原子发射光谱(GC-AED)联用技术,建立了一种DNTF的非含能非自身标样定量测定方法;通过对比DNTF和5种非含能材料(二苯胺、苯甲酸、乙酰苯胺、DBS、DBP)的C元素标准曲线,选择相对定量响应因子最接近1的非含能材料作外标物定量DNTF的C元素,再结合分子式对DNTF进行定量.结果表明,苯甲酸的相对定量响应因子最接近1,用苯甲酸的C元素标准曲线定量DNTF的C元素,得到DNTF的C元素线性范围为17.43～426.92μg/mL,相关系数(r)为0.9992;以3倍信噪比计算检测限,得到DNTF的C元素方法检测限为0.0096μg/mL;相同条件下,DNTF在线性范围内高、中、低浓度下的加标回收率分别为104.9％,103.7％和109.4％,相对标准偏差分别为3.3％、1.1％和1.5％;该方法具有较好的准确度和精密度,可以实现在自身标准物质缺乏的情况下用非含能材料作外标物对DNTF的准确定量.

利用气相色谱-原子发射光谱(GC-AED)对DNAN进行了定量和元素比例式推断的方法研究.以二苯胺为外标物,通过二苯胺的C元素标准曲线定量DNAN的C元素,进而对DNAN的含量进行测定.同时,将乙酰苯胺作为内标物,通过不同的元素通道定量测定DNAN的所含元素,进而推断DNAN的元素比例式.研究表明GC-AED法具有较好的准确度和精密度,能够解决标准样品缺乏带来的定量检测难题.此外,推断得到元素比例式中的各原子比和理论分子式中的各原子比基本一致,证明GC-AED法用于推断元素比例式可行.