基于纳米铝粉表面共价修饰的核壳型含铝炸药的构筑与释能机制研究

Poor compatibility between aluminum nanoparticles and polymeric adhesives and low efficiency of aluminized explosives is a basic issue we face in the study and application of aluminized explosives. Surface grafting is an effective route to improve the interfacial compatibility; however, traditional coating has an negative influence on integrity of the film and reactivity of aluminum nanoparticles. It is difficult to deliver energy when explosives and aluminum powders separate as individual islands. Based on the construction of composite microstructure of energetic materials, the aluminum nanoparticles, which are grafted by covalent modification, will be grafted onto explosive crystal to form ordering sore-shell structures. Firstly, intermediates with specific functional groups connect energetic molecular and nano-aluminum; By varying contents of energetic polymer, reacting time, the surface properties, grafting thickness and compatibility can be tuned. Then, modified aluminum are assembled on explosive crystal to prepare lychee-like aluminized explosives, and to realize efficient release of energy. By employing GAP as model polymers, the surface properties will be precisely controlled; Based on the design of core-shell structure, the aluminized explosives with different layer density will be obtained through adjusting relative ratios, and the relationship between microstructure and energetic release will be discussed. This research effort is to provide new means for surface grafting of metallic nanoparticles; tunable core-shell structure of explosives can present supportive basis for the rules of energetic release of aluminized explosives.

纳米铝粉与有机粘结剂亲和性差以及含铝炸药释能效率低是当前含铝炸药研究和应用中普遍关心的基本问题。表面接枝是改善界面相容性的有效途径，但传统的表面包覆影响膜层的完整性以及纳米铝粉的反应活性，含铝炸药中炸药与铝粉形成岛状分离，难以实现能量的有效传递。本项目拟从含能材料复合微结构构筑出发，基于一种纳米铝粉表面共价键修饰的方法，与炸药形成有序化“荔枝型”核壳结构：首先通过带有特定官能团的中间体桥接，实现含能高分子在纳米铝粉表面的共价键接枝，并通过调节含能高分子反应量、反应时间对铝粉表面性质、包覆厚度、与有机粘接剂相容性进行可控调节；再通过改性铝粉在炸药表面组装包覆制备“荔枝型”含铝炸药，实现能量高效率释放。拟采用聚叠氮缩水甘油醚（GAP）作为接枝含能高分子，研究其对纳米铝粉表面性质的调节规律；基于核壳型含铝炸药的设计，调控相对比例，制备出不同铝粉包覆厚度的含铝炸药，探讨微结构与能量释放之间的关系。

纳米铝粉团聚、氧化失活使得纳米铝粉难以在含铝炸药中广泛使用，针对纳米铝粉普通的物理修饰难以包覆完整及钝感化学高分子接枝处理无法满足能量需求的问题，本项目以构建纳米/微米复合粒子含铝炸药出发，选用HMX作为炸药模型，周围包覆功能化的纳米铝颗粒，形成二次"核壳"结构。对于纳米铝粉，以聚叠氮缩水甘油醚（GAP）作为接枝含能高分子，利用可控接枝方法，开展其对纳米铝粉表面性质的研究；对于炸药HMX，通过对炸药表面的预修饰以及对纳米铝粉的有序包覆的调控，获得"荔枝型"核壳结构以及含能GAP的存在对含铝炸药能量释放的影响规律。主要包括以下两条内容：（1）纳米铝粉表面的可控接枝，含能高分子的生长规律；（2）纳米/微米复合粒子含铝炸药结构与能量释放的关系。最终掌握了铝粉表面接枝含能高分子的方法，该方法具有通用性，可以用于50纳米到10微米的铝粉包覆。同时，构建的HMX@(Al@GAP)结构，有利于改善炸药与粘结剂的接触面积，提升力学性能；还能利用GAP的含能效应，更多铝粉参与爆轰区反应，最终爆速、爆压协同提升。该含能高分子接枝方法可以用于表面含羟基的无机材料包覆，另外，构筑的双核壳结构也为含铝炸药设计提供新思路。