Study On The Micro-nano Structure Of Ammonium Perchlorate And It’s Anti-hygroscopicity Property

Ammonium perchlorate（AP）is widely used as oxidizer in military and aerospace field for it’s high oxygen content.But in practical application process,AP is easy to absorb moisture that affects its performance,therefore,it is necessary to modify AP to reduce its hygroscopicity.At present,The research of AP is reported numerously,but it is not yet reported that the improvement of AP anti-moisture absorption performance from the combination of micro-nano structure and surface treatment.In this paper AP/SiO₂ composites and AP/CBC nanostructured materials were parepared by AP micro-nano structure and surface treatment technology.The main research contents were as follows :1.Preparation and characteried of AP/SiO₂ composites.AP/SiO₂ composites were prepared by sol-gel method,and adopts Polymethylhydrosiloxane（PMHS）,Dodecafluoroheptylpropyltrimethoxysilane（FAS）and Methyltriethoxysilane（MTES）as the surface modifier of AP/SiO₂ composite material surface modification,in order to improve anti hygroscopicity of composite materials.The morphology,structure and moisture absorption properties of AP/SiO₂ composites were characterized using fied emission scanning electron microscopy,X-ray diffraction（XRD）,fourier transform infrared spectrometer（FI-IR）,temperature and humidity chambertesterand and water contact angel test.The results showed that AP,SiO₂ and modifier were organically combined,AP was uniformly filled in the pores of SiO₂ and the surface was coated with a layer of surface modifier.The contact angle test showed that the contact angle of pure AP was 0 degrees,and the contact angle of the AP/SiO₂ composite modified by PMHS,FAS and MTES was（64 ± 2）°（50 ± 2）°（42 ±2）° respectively,and the relative to the pure AP was greatly improved.The moisture absorption test showed that the moisture absorption rate of AP was1.13% after 48 h,and the hygroscopicity of the modified AP/SiO₂ composite was less than that of pure AP,and the moisture absorption of the AP/SiO₂ composite modified by PMHS was only about 0.24%.2.Preparation and characteried of AP/CBC nanostructured materials.Hydrophobic AP/CBC nanostructured materials was prepared by the solutiondipersion-freeze drying method with ammonium perchlorate（AP）and carbonized bacterial cellulose（CBC）as raw materials,and used Polymethylhydrosiloxane（PMHS）,Dodecafluoroheptylpropyltrimethoxysilane（FAS）and Methyltriethoxy-silane（MTES）as modifying materials for further modification.The morphology,structure and moisture absorption properties of AP/CBC nanostructured materials were characterized using fied emission scanning electron microscopy,X-ray diffraction（XRD）,fourier transform infrared spectrometer（FI-IR）,temperature and humidity chambertesterand and water contact angel test.The results show that AP uniform distribution in the there-dimensional network porous of CBC and after modification,the surface of the AP/CBC nanostructured materials was covered by modifying agent,which is helpful to the formation of hydrophobic suface.Contact angel measurement showed that the contact angel of the modified AP/CBC nanostructured materials were（109 ± 2）°（56 ± 2）°（55 ±2）°respectively corresponding to PMHS,FAS,MTES,and the relative to the pure AP was greatly improved.The moisture absorption test showed that after 20 days,the moisture absorption of AP/CBC nanostructured materials was less than that of pure AP,and the lowest moisture absorption of AP/CBC nanostructured materials was only 0.31% after modified by PMHS.In this study,we selected the appropriate structural materials to construct the AP complex with special structure,and then used hydrophobic modifier to modify the hydrophobic surface of AP composite,It not only improves the moisture absorption property of AP,but also provides a new thinking for the study on the hydrophobic transition of water-soluble salts.