液态氟橡胶改性端羟基嵌段共聚醚粘合剂及其对铝粉热氧化行为的影响

Modification of Hydroxyl-terminated Polyether Binder by Liquid Fluororubber and Its Effect on Thermal Oxidation Behavior of Aluminum Powder

利用氟化物促进铝粉的燃烧是近年来含能材料领域的热点。选用含氟量较高的端羟基液态氟橡胶作为氟源,将其引入端羟基嵌段共聚醚(HTPE)粘合剂体系中,制备不同氟橡胶含量的改性HTPE胶片,并对改性胶片的微观形貌、力学特性、热稳定性和氧化能力进行测试分析。结果表明:随着液态氟橡胶含量的增加,胶片的力学性能先降低后增加,当氟橡胶质量分数为50%时胶片拉伸强度和断裂伸长率分别为2.51 MPa和217%,与未改性HTPE胶片相比,拉伸强度增加了83%,断裂伸长率降低了17%;液态氟橡胶的引入促进了HTPE聚氨酯粘合剂的分解,初始分解温度由263 ℃提前到209 ℃;改性粘合剂分解释放的含氟氧化性气体与铝粉的氧化铝外壳反应生成AlF_(3),促进内部活性铝核的释放。

The combustion of aluminum powder promoted by fluoride is a hot spot in the field of energetic materials in recent years.Hydroxyl terminated liquid fluororubber with high fluorine content is selected as fluorine source,which is introduced into hydroxyl-terminated polyether (HTPE) adhesive system to prepare modified HTPE films with different fluorine rubber contents.The morphology,mechanical properties,thermal stability and oxidizability of the modified HTPE films were tested and analyzed. The results show that the mechanical properties of the film decrease first and then increase with the increase in fluororubber content.The tensile strength and elongation at break of the film with fluororubber content of 50 wt% are 2.51 MPa and 217%,respectively. Compared with the unmodified HTPE film,its tensile strength is increased by 83%,and its elongation at break is decreased by 17%. Liquid fluororubber promotes the decomposition of HTPE polyurethane adhesive,and the initial decomposition temperature shifts from 263 ℃ to 209 ℃.The fluorine-containing oxidizing gas decomposed by the modified adhesive reacts with the alumina shell of aluminum powder to form AlF_(3),which promotes the release of internal active aluminum core.