【作者】 虞振飞；

【导师】 崔国良；

【作者基本信息】 北京理工大学 ， 材料科学与工程， 2016， 博士

【摘要】 高能固体推进剂中各种组分之间的物理相容性是评价固体推进剂使用可靠性与贮存安定性的一项重要指标。本文运用分子模拟软件Materials Studio(版本5.5)进行高能固体推进剂中关键组分的物理相容性研究,与实验结果、理论规律相对照分析,并验证了模拟方法的准确性,可为新型高能固体推进剂的研制提供理论支撑与技术指导。主要研究内容和结果如下:(1)含能增塑剂和中性高分子键合剂(NPBA)对粘合剂-固体填料相互作用的影响。分子模拟计算得到的结合能数据、径向分布函数曲线、溶度参数值表明,不同的粘合剂/增塑剂体系获得的数据具有相同规律,含能增塑剂削弱了粘合剂-固体填料之间的相互作用,而NBPA能增强这种相互作用,且其效果优于(硝化纤维素)NC。与实测的力学性能数据有较好的一致性,说明搭建的分子模型和计算方法可以用于考察NPBA在高能固体推进剂中应用的效果。(2)不同种类衬层中硝酸酯迁移的分子动力学模拟。分子动力学计算所获得的衬层和硝酸酯等组分的内聚能密度、溶度参数、表面张力等模拟计算值均为聚二甲基硅氧烷(PDMS)<端羟基聚丁二烯(HTPB)<聚乙二醇(PEG),与这些组分的极性大小顺序一致,而接触角模拟值的逻辑顺序也相一致;硝酸酯增塑剂硝化甘油(NG)和1,2,4-丁三醇三硝酸酯(BTTN)在各种衬层中扩散系数的顺序为PEG/N-100>HTPB/IPDI>PDMS/TEOS,与理论趋势和实验测定值有较好的一致性,说明衬层阻挡硝酸酯增塑剂迁移的效果按照这一顺序依次增强。另外,在同种衬层中,NG的扩散系数大于BTTN,说明NG比BTTN易于迁移。同时证明了所采用的模拟计算方法和步骤可信,能够较为准确地研究硝酸酯增塑剂在衬层中的迁移情况。(3)硝酸酯增塑剂在聚氨酯弹性体中迁移的介观模拟。耗散粒子动力学(DPD)模拟计算的NG和BTTN扩散系数结果分别为1.80×10-12 m2/s和0.21×10-12 m2/s,与微观模拟数据、文献报道值、实测数据较为符合,且随预聚物相对分子质量、温度的提高而增大,与理论趋势相一致。同样条件下,NG的扩散系数大于BTTN,说明NG在高能固体推进剂中的迁移量要比BTTN大。同时证明了搭建的粗粒化模型可以在更大的时间和空间尺度上考察聚氨酯中硝酸酯增塑剂的扩散情况。(4)中性高分子键合剂在含能增塑剂∕粘合剂预聚物中相分离的介观模拟。介观模拟计算得到333K和303K时NPBA在TMETN/BDNPF_A/BAMO/NMMO、TMETN/BDNPF_A/PEG、NG/BTTN/PEG这三种含能增塑剂/预聚物混合体系中的有序度分别为3.63、4.14、0.61和7.93、9.23、2.74,说明低温时相分离程度更大。另外,NPBA的效果比NC好,说明NPBA改善力学性能的原因是NPBA在粘合剂与固体填料之间发挥了“分子桥”的作用,增强了二者之间的作用,而不是像NC那样仅仅使粘合剂网络结构更加紧密。与宏观力学性能数据之间存在较好的对应关系,证实本文的介观模拟计算方法和结果可信,从而能够在合成NPBA之前就对其使用效果有较为清晰的认识,为其分子设计、合成及应用提供及时、准确的参考。更多还原

【Abstract】 The interaction between components in high energy solid propellant, i.e. compatibility,is an important indicator to evaluate its performance and storage stability. Physical compatibility of related components in high energy solid propellant was simulated by Accelrys Materials Studio. Simulation data are consistent with reported experimental and theoretical results. The simulation method was verified, thus it can supply theoretical support and technical guidance for developing new propellant. The main contents and results were as follows:(1) Interaction of binder-solid filler affected by energetic plasticizers and neutral polymeric bonding agents(NPBA). Simulation data of binding energy, radial distribution function profile and solubility parameter data are consistent with reported experimental results of mechanical properties. The method was verified and thus can be used for developing of neutral polymeric bonding agent in high energy solid propellant.(2) Diffusion of nitrate plasticizer molecules in different propellant liner. Simulation data of cohesive energy, solubility, surface tension, interface energy, contact angle and diffusion coefficient of nitrates and liners are consistent with theoretical trends and reported experimental results. The method was verified and thus can be used for studying of migration of nitrates in liners of high energy solid propellant.(3) Mesoscopic simulation of migration of nitrates in polyurethane. Mesoscopic simulation data of diffusion coefficient is at the same order to microscopic results reported in literature and experimental results. And effect of molecular weight of prepolymer,temperature and content of nitrates on diffusion coefficient is consistent with theoretical trends. The method was verified and thus can be used to investigate migration of nitrates in polyurethane at larger time and space scale.(4) Mesoscopic simulation of phase separation of NPBA in energetic plasticizer /prepolymer system. Simulation data of order parameter agrees well with reported experimental results of mechanical properties. And effect of molecular weight of NPBA,processing temperature and percent of NPBA in the mixture on phase segregation can be explained by related theory of polymer solution and indicate the mesoscopic simulation method can be used for verifying of NPBA molecular design in a straightforward way before its synthsis.更多还原