Synthesis Of Fullerene Anisole、Aniline Derivatives And Their Effects On Thermal Stability Of Nitrocellulose

Nitrate compounds are commonly employed as energy materials in solid propellants,however their molecular structure contains low-energy nitrate bonds（O-NO2）,which are prone to decomposition processes when exposed to extreme heat,moisture,acidity,and other factors.Nitrogen oxide acid gas（NOX）and nitrogen oxide radical（NO）are created in considerable quantities.These nitrogen oxides promote the degradation of nitrate compounds,shorten the service life of solid propellants,and can induce combustion or even explosion,which have all resulted in significant losses to my country’s military development.Scientists have developed a series of aniline,phenylurea,and phenol stabilizers to enhance the thermal stability of solid propellants.Aniline stabilizers produce a large number of carcinogens due to their strong saponification effect.Although phenylurea and phenol stabilizers are not strong saponifiers,their low alkalinity causes them to absorb nitrogen oxides weakly and to absorb acid gas inefficiently.Fullerene has a high capacity to absorb free radicals and is compatible with energetic components used in propulsion.It is a promising material for use as a replacement for traditional stabilizers in solid propellants.This topic combines fullerenes with benzyl alcohol or aniline small molecules that have particular stable properties to properly break the fullerene to improve the absorption activity of fullerene materials for nitrogen oxides（nitroxide radicals and acid gases）.The effect of fullerene derivatives on the thermal stability of nitrocellulose was investigated using the stability test technique,and a series of functional fullerene derivatives were designed and synthesized to increase the chemical activity of the big,delocalized system.This paper’s research content is divided into 4 parts:（1）A fullerene benzopyran-type monoaddition derivative（2b）and four kinds of 1,4-monoaddition fullerene anisole derivatives（2a,3b,2c,2d）were synthesized via the nucleophilic reaction of chlorofullerene by using hexachlorofullerene and anisole as raw materials.NMR,HRMS,FT-IR,UV-Vis,and single-crystal XRD were used to confirm their molecular structures;（2）The nucleophilic interaction of octabromofullerenes and aniline small molecules yielded five kinds of monoaddition aziridine fullerene derivatives（5a-e）and three kinds of bis-adduct aziridine fullerene derivatives（6a-c）.NMR,HRMS,FT-IR,UV-Vis,and single-crystal XRD were used to confirm their molecular structures;（3）The compatibility and stability of fullerene anisole stabilizers（2a,2b,3b,2c）and nitrocellulose were investigated by differential scanning calorimetry,methyl violet experiment,vacuum stability test,isothermal thermogravimetric experiment,and adiabatic accelerated calorimetry experiment.The stability sequence is as follows: 3b > 2d > 2a > 2c > C2 > 2b >DPA,with the performance clearly superior to that of traditional stabilizers C2 and DPA.Finally,FT-IR spectroscopy and ESR tests were used to investigate the mechanism of fullerene-based stabilizers on nitrocellulose.The order of capacity to scavenge free radicals and the stabilizing process are consistent with the preceding;（4）Differential scanning calorimetry,methyl violet experiment,vacuum stability test,and isothermal thermogravimetric experiment were used to evaluate the compatibility and stability of aziridine fullerene derivatives（5a-e,6a-c）and nitrocellulose.The stability sequence is as follows: 6c > 6b > 6a > 5c > 5e > 5b > 5d > 5a > C2 > DPA,with the performance clearly superior to that of traditional stabilizers C2 and DPA.Finally,ESR tests were used to investigate the mechanism of fullerene-based stabilizers on nitrocellulose.The order of capacity to scavenge free radicals and the stabilizing process are consistent with the preceding.The study reveals that the functional fullerene derivatives developed have high compatibility with nitrocellulose,may effectively prolong nitrocellulose storage life,improve safety during production and use,and outperform traditional stabilizers（C2 and DPA）.By increasing the number of substituents on the benzene ring and lengthening the carbon chain length of the para-substituents on the benzene ring,the stability performance may be enhanced.As a result,fullerene anisole and aniline derivatives may be used to replace traditional stabilizers.