【作者】 李宁；

【导师】 周伟良；

【作者基本信息】 南京理工大学 ， 材料科学与工程， 2013， 博士

【摘要】 现代先进武器系统对弹药提出了大威力和高生存能力的要求,研究开发低敏感高能发射药成为21世纪发射药及其装药发展的重要趋势之一。传统发射药的敏感性是由硝化棉和硝化甘油内在的热分解特性决定的。因此,发展低敏感高能发射药的关键是获得能替代硝化棉和硝化甘油等传统含能材料的低感度高能添加剂和性能优良的含能粘结剂。在这类发射药研究中,国内目前研究一般以交联固化型的GAP、AMMO等作为含能粘结剂,但它们存在需要加入固化剂、返工品处理困难等缺点,而综合性能优良的含能热塑性弹性体又由于技术原因未能用于发射药配方的试制；低感度高能添加剂可通过对高能添加剂进行表面包覆来获得,但采用的惰性包覆材料又会对它们的能量性能产生消极的作用。适用的含能热塑性弹性体和高能量低感度高能添加剂的合成和制备技术是低敏感高能发射药研究的难题。本课题从含能热塑性弹性体(ETPE)的角度入手,为解决当前低敏感高能发射药研究中存在的难题,设计了以GAP基含能热塑性弹性体为粘结剂、以含能热塑性弹性体包覆过的RDX作为主要高能添加剂的高能发射药。通过配方设计、能量分析、粒度级配研究、高能添加剂包覆钝感处理、成型加工工艺研究等阶段制备得到了具有较好力学强度、燃烧稳定的ETPE基高能发射药。从性能、来源、成本等方面对发射药组分进行选择。确定RDX作为发射药的主要能量来源,以CL-20为辅助的高能添加剂；确定以GAP基含能热塑性弹性体与硝化棉作为发射药用含能粘结剂,含能增塑剂可根据不同需要进行适当选择。通过能量计算软件对发射药配方进行能量特性分析。相同火药力的不同配方中,ETPE含量较高的配方具有较大的比容与较低的爆温。发射药RDX/ETPE/NC/A3(ETPE/NC=50/50)的固含量为70%时,火药力可达到1190kJ·kg-1以上,爆温3210K左右。以BTTN作为增塑剂的RDX/ETPE/NC/BTTN (ETPE/NC=70/30)发射药配方在较宽的配比范围内火药力都能达到1200kJ·kg-1.采用振实密度仪对RDX颗粒进行粒度级配研究。两种粒径的颗粒按照粗细7：3的比例进行混合使用可使体系的堆积率最高。含三种粒径的颗粒进行堆积时,粒径由大到小按照7：1：2或者6：1：3的比例堆积,可得到最大堆积率。通过沉淀法采用含能热塑性弹性体对RDX进行表面包覆,获得了较高能量的低感度RDX。按照包覆量1%、包覆温度30℃、包覆时间30min、助剂量1.5m1的包覆条件所制得的样品,XPS分析得出包覆度为72.5%；有机元素分析确定包覆层质量分数为0.98%,与投料值1%基本相当；RDX的撞击感度特性落高从25.6cm提高至47.9cm,摩擦感度爆炸百分数由72%降至40%。包覆后的RDX颗粒较包覆前的RDX颗粒具有良好的流散性,安息角从51.6°下降到40°左右；采用包覆过的RDX的发射药混合物料具有较低的药浆粘度。以硝化棉作为载体吸附ETPE得到混合粘结剂微粒,有效改善了含ETPE的发射药的物料混合均匀性,并通过溶剂法经压伸成型制备得到了高RDX含量(>70%)的ETPE基高能发射药样品。药粒的抗压强度可达30MPa以上,火药力1170kJ·kg-1-1210kJ·kg-1.定容燃烧试验中,随RDX含量的增加,发射药的燃速加快；发射药在燃烧过程中压力波动不明显,在不同的压力区间具有不同的燃速压力指数。发射药配方RDX/ETPE/NC (77.9/10.9/10.9)与RDX/CL-20/ETPE/NC (64.7/10.3/12.4/12.4)实测火药力分别达到1215kJ·kg-1与1251kJ·kg-1,定容燃烧实验中,dp/dt-t及L-B曲线表明发射药的燃烧过程均较稳定,且具有较好的力学强度,该发射药配方具有进一步研究的意义。更多还原

【Abstract】 The continuing demand for high performance and low vulnerability of ammunition in the advanced weapon system makes insensitive high energy propellants the most promising trend of gun propellants and charges in the21st century. The sensitivity of traditional propellant is determined by the thermal decomposition characteristics of nitrocellulose and nitroglycerine. So getting some new high energy additives and binders with low sensitivity which can alternative the normal energetic materials such as nitrocellulose and nitroglycerine plays a key role in the development of insensitive high energy propellant.However, some crosslinking binders needing curing agent to mold are the main energetic binders in current domestic research of insensitive high energy propellant instead of energetic thermoplastic elastomers (ETPE) with excellent performance due to technical reasons.The sensitivity of high energy additives particles can be reduced by surface coating, and the coating materials should be energetic as far as possible to avoid energy loss. Unfortunately, both of the two problems remain to be solved.To solve the problems, the thesis designed a high energy propellant based on GAP-ETPE, containing GAP-ETPE as binder and RDX which is coated by GAP-ETPE as high energy additive.The propellants with good mechanical strength stable combustion were prepared via several steps:formulation design, energy analysis, particle size gradation, surface coating of high energy additives and molding process study.The components of the propellants were seclected according to the properties, resources, cost, etc. RDX is the main energy source of the propellant while CL-20can be used as the assisted high energy additive. GAP-based energetic thermoplastic elastomers and nitrocellulose were chosen to be the energetic binder, and different energetic plasticizers can be used in different conditions.The analysis of energy characteristics of the propellant formulations were carried out by the programmed energy calculation software. The higher the ETPE content is, the higher the specific volume and the lower the explosion temperature are when formulations with the same impetus. The impetus can be more than1190kJ-kg"1when the RDX content of propellant RDX/ETPE/NC/A3(ETPE/NC=50/50)is70%and the explosion temperature is around3210K. The impetus of the propellant RDX/ETPE/NC/BTTN (ETPE/NC=70/30) can reach1200kJ·kg-1within a wide range.The study of RDX particle size gradation was carried out by tap density tester. In binary packing mixtures, the packing efficiency can reach the maximum value when the volume fraction of coarse-fine RDX particles is7:3. The packing efficiency can reach the maximum value when the volume fraction of coarse-middle-fine glass beads is7:1:2or6:1:3in ternary packing mixtures.GAP-based energetic polyurethane elastomer was introduced to coat RDX by liquid precipitation method. Coating conditions were as follows:coating amount(1%), coating time(30min), coating temperature(30℃), precipitant(1.5ml).It is found that the flowability improves obviously compared to uncoated RDX. It is experimentally shown that coating degree R is72.5%and the mass fraction of coating layer is0.98%, which agrees well with the initial value(1%). By coating of RDX with1%GAP-ETPE, the characteristic height of impact sensitivity (H50) of RDX particles is increased from25.6cm to47.9cm, and the friction probability is reduced from72%to40%.The dynamic viscosity of propellant slurry is lower when containing coated RDX.The thesis prepared binder particles by using NC as a carrier to absorb ETPE which is greatly improving the uniformity of mixing propellant materials, and then the ETPE-based high energy propellants with high RDX content(>70%) were prepared via solvent method and extrusion. The compression strength of the propellants can be above30Mpa and the impetus is from1170KJ·kg-1to1210kJ·kg-1. In constant-volume combustion experiments, the higher RDX content is, the faster burning speed is. The fluctuation of the pressure is not obvious during the burning process and the propellants have different burning rate pressure exponents in different pressure ranges.The measured impetus of the propellant formulations RDX/ETPE/NC (77.9/10.9/10.9) and RDX/CL-20/ETPE/NC (64.7/10.3/12.4/12.4) are1215kJ·kg-1and1251kJ·kg-1, respe-ctively. In constant-volume combustion experiments, the dp/dt-t and L-B curves showed that the burning process of the propellants were both fairly stable, and considering their better mechanical strength, the further research of the propellant formulations is meaningful.更多还原