硬脂酸钙对CL-20/Estane复合粒子性能的影响

以CL-20为主体炸药、Estane5703为黏结剂、硬脂酸钙(CaSt2)为增塑剂,采用水悬浮法制备了4种复合粒子。用SEM、XRD、DSC对目标产物进行了表征及性能测试。结果表明,水悬浮法可以使硬脂酸钙和Estane5703成功包覆在CL-20晶体的表面,CL-20的晶型仍为ε型,说明硬脂酸钙不会改变CL-20主体炸药的晶型。加入硬脂酸钙后,CL-20/Estane复合粒子的特性落高从34.8cm升至39.8cm,热稳定性有所改善;当硬脂酸钙的质量分数为0.5%时,CL-20/Estane包覆样品的热爆炸临界温度提高了5.81℃。     

CL-20/FOX-7/蜡复合粒子的制备及性能研究

为了提高六硝基六氮杂异伍兹烷(CL-20)的安全性,采用水溶液-悬浮法将FOX-7、微晶蜡包覆在CL-20表面,制备了4种包覆样品;采用扫描电子显微镜法(SEM)、X-射线衍射法(XRD)、傅里叶变换红外光谱法(FTIR)、X射线光电子能谱法(XPS)、差示扫描量热法(DSC)、感度测试法对其微观形貌、晶型、结合方式、包覆效果、耐热性、摩擦感度进行了系统测试分析。结果表明,4种包覆样品均为物理复合,CL-20晶型未发生改变,其中水悬浮法制得的CL-20/FOX-7混合物与机械混合物相比,CL-20表面存在更多的FOX-7粒子,其包覆率为49.83%,热分解峰温为242.79℃,摩擦感度的临界载荷为168N;在混合物中加入微晶蜡后,复合粒子呈类球形,CL-20晶体几乎无外露,但微晶蜡加入的方式对复合粒子性能有较大影响,蜡外包样品的包覆率为64.73%,热分解峰温244.98℃,摩擦感度的临界载荷为360N,较蜡内包样品包覆率提升了5.03%,热分解峰温提升了2.31℃,摩擦感度的临界载荷提升了144N。表明采用FOX-7、微晶蜡可共同对CL-20进行包覆改性,且蜡外包的样品综合性能最好。     

水性聚丙烯酸酯顿感包覆CL-20

以CL-20(六硝基六氮杂异伍兹烷)为主体炸药、水性聚丙烯酸酯为胶粘剂,采用泥浆法制备了CL-20基PBX(聚合物粘接炸药)。通过FE-SEM(冷场发射扫描电镜)、XRD(X射线衍射)法对PBX的性能进行了表征。研究结果表明:泥浆法可使水性聚丙烯酸酯成功包覆在CL-20颗粒表面,包覆前后CL-20的晶型没有变化,包覆后CL-20的撞击感度明显降低,其热安定性更好。     

黏结剂对CL-20/FOX-7基PBX性能的影响

为了研究黏结剂对CL-20/FOX-7基PBX性能的影响,分别以Estane、EPDM、ACM、EVA为黏结剂,采用水悬浮法制备了含有不同黏结剂成分的CL-20/FOX-7基高聚物黏结炸药(PBX);采用场发射扫描电子显微镜(SEM)、激光粒度分析仪、X射线衍射仪(XRD)、差示扫描量热仪(DSC)对样品结构、形貌和热分解特性进行了表征;使用撞击感度测试仪、摩擦感度测试仪和小型烤燃实验装置测试了不同样品的机械感度和烤燃特性。结果表明,以EVA为黏结剂制备的CL-20/FOX-7基PBX造型粉颗粒密实,表面光滑且没有脱粘外漏现象,包覆粘结效果最好;以EVA为黏结剂制备的PBX活化能较细化CL-20提高了87.75 kJ/mol,较FOX-7原料提高了42.52 kJ/mol,说明使用EVA的PBX热稳定性较原料有一定提升;同时该PBX样品特性落高(H 50)较细化CL-20提高25.6 cm,摩擦感度爆炸概率降低52%,较使用Estane、EPDM和ACM的PBX样品机械感度更低;使用EVA的PBX药柱在升温速率为6K/min的慢速烤燃条件下,烤燃反应等级为燃烧,说明该配方能够达到烤燃安全试验要求,安全性能较好。     

增塑剂类型对CL-20/HTPB基浇注炸药安全性能的影响

为确定CL-20(六硝基六氮杂异伍兹烷)/HTPB(端羟基聚丁二烯)基PBX(聚合物粘接炸药)配方中最适宜的增塑剂类型,分别制备了含不同增塑剂[如DOA(己二酸二辛酯)、DOS(癸二酸二辛酯)和DBP(邻苯二甲酸二丁酯)等]和不含增塑剂的浇注PBX。着重探讨了不同浇注PBX的热分解动力学参数、撞击感度及临界爆炸温度。研究结果表明:与不含增塑剂体系相比,增塑剂对浇注PBX的热分解峰温影响不大,但均能提高其E(表观活化能),其中含DOS或DBP体系的E值均提高了13%左右;含DBP体系的临界爆炸温度更高,说明该体系具有更好的热安定性;含增塑剂体系的感度明显低于无增塑剂体系,其中含DBP体系的H50(特性落高)值比无增塑剂体系提高了近2倍。     

EPDM对CL-20的包覆及表征

以CL-20为主体炸药、EPDM为黏结剂,采用水悬浮法制备了CL-20基PBX炸药,用SEM、XRD和FT-IR对产物进行了表征,并测试了其撞击感度和热安定性。结果表明,该包覆工艺可使EPDM成功地包覆在CL-20表面,在包覆过程中CL-20晶型没有发生变化。与原料CL-20相比,包覆样品的撞击感度明显降低,特性落高由15.9cm提高到40.7cm,热安定性更好。     

不同胶粘剂对RDX降感效果的对比研究

为降低RDX(黑索金)炸药的机械感度,分别采用5种惰性胶粘剂[如F2602(氟橡胶)、F2604(氟橡胶)、EPDM3720(三元乙丙橡胶)、PVAc(聚醋酸乙烯酯)和Estane5703(热塑性聚氨酯)等]作为包覆剂,对RDX表面进行包覆处理。研究结果表明:不同胶粘剂均可成功包覆在RDX颗粒表面;包覆RDX的撞击感度随胶粘剂比例增加呈先升后降态势;F2602和F2604包覆RDX的摩擦感度随胶粘剂比例增加而增大,而其他3种胶粘剂的摩擦感度则随之下降。     

CL-20/TATB混合物的制备及性能表征

为了提高六硝基六氮杂异伍兹烷(CL-20)的安全性,采用机械混合法和重结晶法分别制备了CL-20/TATB混合物;通过光学显微镜、扫描电子显微镜(SEM)、X-射线衍射(XRD)、差示扫描量热仪(DSC)、感度测试仪对其形貌、晶型、热稳定性、机械感度进行测试分析。结果表明,机械混合后CL-20表面无明显包覆物,而重结晶混合粒子表面有一层致密的黄色薄膜,同时两种混合物中CL-20的晶型仍为ε型,未发生晶型转变;两种混合物的热分解表观活化能较原料CL-20分别提高了17.3、117.36kJ/mol,热爆炸临界温度分别提高了0.12、3.8℃,重结晶混合粒子的热稳定性明显提高;两种混合物的撞击感度(H50)较原料CL-20分别提高了10.4、54.5cm,摩擦感度的临界载荷分别提高了80、60N,表明重结晶混合粒子的机械感度显著降低。     

喷雾干燥法制备ε-CL-20/EPDM复合炸药及其性能表征

以ε-CL-20(六硝基六氮杂异伍兹烷)为主体炸药,三元乙丙橡胶(EPDM)为胶粘剂,采用喷雾干燥法制备了ε-CL-20基PBX(聚合物粘接炸药)。研究结果表明:通过喷雾干燥法可使EPDM成功包覆在CL-20晶体表面,制得的包覆产物为ε-CL-20/EPDM复合炸药;与细化CL-20相比,ε-CL-20/EPDM的撞击感度明显降低,包覆样品的特性落高(H50)值从25.12 cm升至41.36 cm,表观活化能由182.58 k J/mol增至230.24 k J/mol,热爆炸临界温度由244.18℃增至245.60℃,说明ε-CL-20/EPDM复合炸药的热稳定性更好。     

工艺温度对F2604/HMX复合粒子包覆效果及撞击感度的影响

为了解工艺温度对PBX炸药性能的影响,采用相分离法将氟橡胶(F2604)包覆在奥克托今(HMX)表面,制备了F2604/HMX复合粒子;通过扫描电镜(SEM)和X射线光电子能谱(XPS)对复合粒子的微观形貌和元素含量变化进行表征;采用分子动力学模拟不同工艺温度下F2604对HMX包覆效果的影响;采用特性落高法测试了F2604/HMX复合粒子的撞击感度。结果表明,随着温度的升高,样品中的N元素含量先降低后升高,包覆度先升高再降低;当工艺温度为50℃时,复合粒子的表面平滑、规整,N元素含量最低,包覆度为58.25%,包覆效果最好;分子动力学模拟结果表明,50℃时F2604/HMX复合体系结合能最高,为197.24 kJ/mol,形成的F2604/HMX体系最稳定;随着温度的升高,撞击感度特性落高H 50先升高后降低,50℃时样品的特性落高最高,为81.7 cm,与20℃时相比提高了78.8%;50℃时,F2604和HMX之间的相互作用力最强,形成的复合体系稳定性最好,使得包覆和粘结效果增强,从而降低了撞击感度。     

Dynamic mechanical signatures of a polyester‐urethane and plastic‐bonded explosives based on this polymer

The complex shear moduli of the segmented polyurethane Estane 5703p, Livermore explosive (LX)‐14, and plastic bonded explosive (PBX)‐9501, which use this polymer as a binder, have been investigated. Segmented polyurethanes, such as Estane 5703, contain microphase‐separated hard segments in a rubbery matrix of soft segments. LX‐14 is composed of 95.5% 1,3,5,7‐tetranitroazacyclooctane (HMX) explosive with 4.5% Estane 5703 binder. PBX‐9501 is composed of 94.9% HMX, 2.5% Estane 5703p binder, 2.5% nitroplasticizer (NP), and about 0.1% antioxidant Irganox 1010. In the temperature range from ?150 to 120°C, two relaxations were observed as peaks in the loss modulus and tangent delta in Estane 5703p and LX‐14. A third relaxation was found in PBX‐9501. The low temperature relaxation associated with vitrification of the poly(ester urethane) soft segment occurred in the shear loss modulus (G″) at ?29 and ?26°C in Estane and LX‐14, respectively, at 1 Hz. In PBX‐9501 the Estane soft segment glass transition peak, T_g(SS), in the loss modulus occurred at ?40 ± 3°C at 1 Hz. The reduction in soft segment glass transition in PBX‐9501 is clear evidence of plasticization of the soft segment by NP. The apparent activation energy of the maximum in the loss modulus for LX‐14 and PBX‐9501 over the frequency range from 0.1 to 10 Hz was 230 kJ/mole (55 kcal/mole). The hard segment glass transition, T_g(HS), was observed as a peak in the loss modulus at about 70°C. In LX‐14 the transition was observed at lower temperatures (56–58°C at 1 Hz) depending on thermal history. There was a low temperature shoulder on the T_g(HS) of Estane 5703 associated with soft segment crystallinity. Modulated differential scanning calorimetry (MDSC) was used to verify the T_g(HS) in Estane and 50/50 mixtures of Estane with NP. In PBX‐9501 the hard segment glass transition occurred between 65 and 72°C. The presence of NP in PBX‐9501 gave rise to a new transition, T_eu(NP), between 8 and 15°C. This peak is believed to be associated with the eutectic melting of the plasticizer. Returns of fielded PBX‐9501 that were 6 and 11 years old were also measured. Small variations in T_g(SS) and the rubber plateau modulus were observed in these aged samples, consistent with migration of plasticizer and/or very low levels of chain scission. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1009–1024, 2002     

The flowing-afterglow technique,and approach to the study of polymer thermal degradation

We describe here a relatively new analytical method^1–3 for following the thermal reaction history of polymers by quantitatively detecting the evolution of gases and some volatiles by flowing-afterglow spectroscopy. The thermal and oxidative stability of common plastics in many industrial and defense applications is of wide interest. We have studied the evolution of moisture and carbon dioxide from Li₂CO₃/Orlon-filled diallyl phthalate (DAP) composites and have briefly examined the thermal stability of Estane 5703, a polyester-based thermoplastic polyurethane. The results of these preliminary studies have shown the utility of FLAG spectroscopy as a means toward our understanding polymer stability and lifetimes in specified environments. FLAG data, combined with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) data, have extended our knowledge of Li₂CO₃/Orlon/DAP and Estane aging processes. The DAP composites evolve H₂O and CO₂ at near ambient temperatures, and we have described the kinetics of gas evolution and have attempted to describe the mechanism of thermal degradation. In the 25–120°C temperature range Estane 5703 evolves CO₂ as a decomposition product and some adsorbed moisture.     

Synthesis,Characterization and Properties of Nitropolybutadiene as Energetic Plasticizer for NHTPB Binder

The nitration of low molecular weight polybutadiene (PB) by a convenient and inexpensive procedure was investigated. To retain the unique physico‐chemical properties of the plasticizer, it was nitrated to an extent of 10 % double bonds. The product nitropolybutadiene (NPB) was characterized by FT‐IR and ¹H NMR spectroscopy as well as GPC, DSC, and TGA methods. The kinetic parameters for the decomposition of NPB from room temperature to 400 °C were obtained from non‐isothermal DSC. The changes in glass transition temperature (T _g) and inert uncured binder systems were used for determination of its efficiency as plasticizer. NPB was used in cured and unfilled nitro‐hydroxyl terminated polybutadiene (NHTPB) binder. Isothermal thermogravimetric analysis (Iso‐TGA) was employed to determine the migration rate in cured and unfilled HTPB binder systems compared to the dioctyladiphate (DOA) plasticizer. It was found that the exudation of the NPB plasticizer is slower than that of the DOA plasticizer. Thus, the NHTPB/NPB binder system (binder/plasticizer) presents more convenient mechanical properties than HTPB/DOA and is a promising new energetic binder system for polymer bonded explosives.     

LLM-105/CL-20基高能钝感PBX的制备与性能表征

为满足含能材料高能钝感的要求,以CL-20为主体炸药,LLM-105为钝感剂,采用溶液水悬浮法制备了LLM-105质量分数分别为10%、20%、30%的3种LLM-105/CL-20基PBX。通过扫描电子显微镜(SEM)、粉末X射线衍射仪(PXRD)和差示扫描量热仪(DSC)对样品的形貌、晶体结构和热性能进行表征,并测试其机械感度;采用EXPLO5软件计算了其爆轰参数。结果表明,LLM-105/CL-20基PBX样品呈类球形,颗粒密实,粒径约为500μm;PBX中各组分的晶体结构未发生改变;3种配方的热安定性都较好,且随着钝感剂LLM-105含量的增加,LLM-105/CL-20基PBX的热爆炸临界温度呈递增趋势;与原料CL-20相比,3种LLM-105/CL-20基PBX的特性落高分别提高了25.88、33.68、37.18 cm,摩擦爆炸概率分别下降29%、38%、45%;LLM-105质量分数为10%的LLM-105/CL-20基PBX的特性落高与PBX-9501相当,而LLM-105质量分数为20%和30%的LLM-105/CL-20基PBX分别比PBX-9501高16.6%和25.12%;理论爆速分别高381.76、279.2、82.03 m/s。3种配方LLM-105/CL-20基PBX炸药的爆轰性能明显优于PBX-9501。     

高聚物黏结ε-HNIW混合炸药的制备及其感度

为改善原料HNIW(CL-20)的结晶品质并降低其机械感度,采用水悬浮工艺对重结晶制备的ε-CL-20进行了包覆.结果表明,原料CL-20呈多晶型,粒径不均,机械感度与PETN相当;在室温条件下,用乙酸乙酯-石油醚对原料CL-20进行重结晶可制备出晶形规整、粒径均匀的高品质ε-CL-20晶粒,撞击感度较原料略有降低;采...     

Standard Enthalpy of Formation of the Bimolecular Crystal of CL-20 with Tris-Oxadiazolo-Azepine and Its Thermal Stability

The standard enthalpies of combustion and formation of 7H-tris([1,2,5]oxadiazolo) [3,4-b:3′,4′-d:3″,4″-f]azepine, its bimolecular crystal with the γ-polymorph of CL-20, and the γ-polymorph of CL-20 have been experimentally determined. The standard enthalpies of formation of the bimolecular crystal and an equimolecular mechanical mixture of γ-CL-20 with azepine differ by less than 12.8 kJ/mol. This small difference is validated by quantum chemical calculations. It has been experimentally found that the presence of azepine in the bimolecular crystal inhibits the thermal decomposition of γ-CL-20 and increases the thermal stability of γ-CL-20 in the bimolecular crystal as compared to original γ-CL-20.     

一锅法制备CL–20混合炸药的工艺研究

以CL–20为主体炸药,聚氨酯5702为黏结剂,Span60为表面活性剂,通过一锅造粒法制备了CL–20混合炸药。用单因素实验对影响CL–20混合炸药包覆效果和撞击感度的因素进行了研究,对包覆后的CL–20混合炸药的相关性能进行了测试,得到最佳工艺条件:水浴温度65℃,搅拌器电压为90 V,驱溶时间为1 h,2次加入溶剂的量与高聚物的质量比为4:1。