Synthesis Of Fullerene Aromatic Amine Mono-Addition Derivatives And Their Stability On Nitrocellulose

Nitrocellulose?NC?and nitroglycerine?NG?are the mainly energetic material of double-base propellants,which endue the propellants a good dynamic performance.However,nitrate esters are considered as chemically less-stable molecules,their nitrate ester group?CO-NO₂?is easy to undergo cleavage due to the low bonding energy of O-NO₂ bonds during the progress of storage and use.These decomposition products contain nitroxyl radicals and nitrogen oxides,which further accelerate the decomposition of nitrate ester through autocatalysis and release a lot of heat that can cause poor stability and even explosion of propellants.All conventional stabilizers belong to aromatic amines and phenylurea derivatives,the intermediate products of these stabilizers react with NC are carcinogenic.In addition,their thermal stability is poor in high temperature.Therefore,these conventional stabilizers should be replaced as soon as possible,and new stabilizers which possess good thermal stability and are environmentally friendly are should be urgently developed.Fullerenes(C₆₀)have a strong ability to eliminate various free radicals due to its electron-deficient olefin,regard as“free radical sponge”.In this project,based on excellent free radical scavenging ability of C₆₀,we combine C₆₀ with stabilization groups in molecular level by chemical methods,designed and synthesized a series of fullerene mono-addition derivatives.In addition,we study the interaction between these fullerene derivatives and NC and the possibilities of their potential application as nitrocellulose-based propellants stabilizer.The main work includes the following four parts:?1?6 fullerene cyclopropane derivatives with different chain lengths were designed and synthesized via modified Bingel reaction using fullerene and malonamide derivatives as raw materials.Meanwhile,their molecular structures were confirmed by ¹H NMR,¹³C NMR,FT-IR,UV-vis and HRMS,their results were consistent with the expected structure.?2?8 fulleropyrrolidines derivatives with different chain lengths were designed and synthesized via modified Prato reaction using fullerene,N-substituted glycine derivatives and aromatic aldehyde derivatives as raw materials.Meanwhile,their molecular structures were confirmed by ¹H NMR,¹³C NMR,FT-IR,UV-vis,HRMS and X-ray single crystal diffraction,their results were consistent with the expected structure.?3?The compatibility and stability of 14 prepared fullerene aromatic amine derivatives in nitrocellulose were investigated using differential scanning calorimetry,methyl-violet,vacuum stability,and weight loss tests.Results inflected that fullerene aromatic amine derivatives had excellent compatibility with nitrocellulose and their stability were better than the conventional stabilizers C2 and DPA.?4?The stability mechanism between 14 prepared fullerene aromatic amine derivatives and nitrocellulose were investigated using EPR,FT-IR and LC-MS.Their results turned out that new fullerene derivatives could effectively eliminate the nitroxyl radicals and absorb nitrogen oxides released from nitrocellulose decomposition and inhibit the autocatalytic decomposition reaction of nitrocellulose.Hence,the storage life of NC-based propellants is extended.