多功能耦合型核-壳-壳结构高能钝感催化复合材料的可控构筑

Nowadays hexanitrohexaazaisowurtzitane (CL-20) is considered as the third-generation high-energy single-compound explosives with highest energy and practical value. However, the high sensitivity of CL-20 greatly limits its widespread application. In this project, bioinspired fabrication of polyamine (PDA) coated CL-20 and the subsequent in situ deposition of CuO are developed aiming at solving the problems regarding the high sensitivity of CL-20 and the difficult dispersion of combustion catalyst of nano-CuO in propellent. Bionic PDA with ultra-strong adhesion property will be employed to construct PDA thin layer on the surface of various particle-size CL-20 with controlled thickness via theoretical simulation and in situ self-polymerization of PDA, followed by revealing the mechanism of interfacial interaction between CL-20 and PDA, as well as elaborating the sensitivity reduction mechanism of PDA coating towards CL-20. In addition, the electrostatic self-assembling of Cu2+ on the negatively charged surface of PDA, and the subsequent in situ precipitation and low-temperature pyrolysis result in high-performance insensitive core-shell-shell structured CL-20@PDA@CuO energetic composites. The coupling mechanism of the oppositely charged PDA surface towards CuO will be elaborated. The precise control of shell structure and thickness will be realized through controlling reaction conditions, in order to endow CL-20 multifunctional coupling properties including high energy, insensitivity, good dispersion, and catalytic function. Moreover, the prepared high-energy composites will be further verified as solid propellent component so that the action law of the composites towards the sensitivity and combustion property of propellent could be built. Our research will provide novel strategies for designing and fabricating high-performance insensitive multifunctional energetic composites with excellent properties.

六硝基六氮杂异伍兹烷（CL-20）是当今具有实用价值的能量最高的第三代单质高能炸药，但CL-20感度高，严重制约了其大规模应用。本项目针对CL-20感度高及推进剂中燃烧催化剂纳米CuO分散不均匀的难题，基于具有仿生功能的聚多巴胺（PDA）的超强粘附性能，通过理论设计及原位自聚合在不同粒度CL-20表面构筑厚度可控的PDA薄层，揭示两者界面作用机理，阐明PDA包覆对CL-20降感作用机制；再基于PDA表面负电性，静电自组装Cu2+，通过化学沉淀、低温热解构建核-壳-壳结构CL-20@PDA@CuO复合材料，并阐明PDA表面异种电荷对CuO壳层的偶联定位作用机制，通过控制反应条件实现CuO壳层结构、厚度的精确调控，使其具有高能、降感、分散、催化的多功能耦合性，并将其在推进剂中加以验证，建立与推进剂感度和燃烧性能的作用规律。本项目将为设计和构建性能优异的高能钝感催化多功能耦合复合材料提供新思路。

六硝基六氮杂异伍兹烷（CL-20）是当今具有实用价值的能量最高的第三代单质高能炸药，但CL-20感度高，严重制约了其大规模应用。本项目针对CL-20感度高及推进剂中燃烧催化剂纳米CuO难分散的问题，基于仿生聚多巴胺（PDA）的超强粘附性能，通过理论设计及原位自聚合在CL-20表面构筑厚度可控的PDA薄层，揭示两者界面作用机理，阐明PDA包覆对CL-20降感作用机制；再基于PDA表面负电性，静电自组装Cu2+，通过化学沉淀、低温热解构建多功能耦合型核-壳-壳结构CL-20@PDA@CuO复合材料，并阐明PDA表面异种电荷对CuO壳层的偶联定位作用机制，通过控制反应条件实现CuO壳层结构、厚度的精确调控，使其具有高能、降感、分散、催化的多功能耦合性，并在推进剂中加以验证。结果表明：（1）ɛ-CL-20（110）晶面与PDA之间结合能为893.2 kJ/mol，大于ɛ-CL-20（001）和（020）晶面，表明ɛ-CL-20（110）晶面与PDA具有最强的相互作用，说明PDA能够紧密包覆于CL-20表面，有望降低CL-20的机械感度；（2）PDA成功包覆在CL-20表面，CL-20@PDA复合材料的降感效果随反应时间、DA单体浓度变化呈先升高后降低的趋势，当反应时间为9 h，DA单体浓度为2 g/L时，复合材料撞击感度较原料CL-20降低60.5%。此外，通过原位生成法将纳米CuO负载于CL-20@PDA表面，所得CL-20@PDA@CuO复合材料机械感度较原料CL-20降低95.9%，且制备过程对CL-20的晶型无影响；（3）CL-20@PDA@CuO复合固体推进剂与传统推进剂热分解特征类似，在各压力段的燃速压力指数均小于1，表明燃速对压力的依赖性小，满足火箭发动机稳定工作的要求。本项目为设计和构建性能优异的高能钝感催化多功能耦合复合材料提供新思路。