低聚硅倍半氧烷在HTPB复合推进剂中的多功能作用

To improve the comprehensive performances of composite solid propellants, four types of polyhedral oligomeric silsesquioxane(POSS)with organic-inorganic hybrid structure, including octa(phenyl)silsesquioxane(OPS), octa(nitrophenyl)silsesquioxane(ONPS), octa(dinitrophenyl)silsesquioxane(ODNPS)and octa(aminophenyl)silsesquioxane(OAPS)with different mass fractions were applied to HTPB propellants. The electronic universal testing machine and thermomechanical analyzer were used to measure the tensile mechanical properties of the propellants. Oxygen bomb calorimeter was used to measure the heats of explosion of the propellants under 3MPa nitrogen atmosphere. CCD line scan camera was used to measure the burning rate—pressure relations of the propellants. The morphology, particle size and the condensed-phase combustion products after the explosion heat test of the propellants were analyzed by scanning electron microscope, laser particle size analyzer and X-ray diffractometer(XRD). The synchronous thermal analyzer, scanning electron microscope(SEM), transmission electron microscope(TEM)and X-ray photoelectron spectroscopy(XPS)were used to analyze the effect of POSS on the combustion mechanism of the propellants. The results show that four kinds of POSS can improve the tensile properties of the propellants, and the effect of OAPS is the best. Four kinds of POSS can increase the burning rate of the propellants. When the mass fraction of ONPS is 3%, the burning rate and explosion heat of the propellant are the highest. Four kinds of POSS can promote the combustion of aluminum in the propellants, the particle size of the condensed-phase combustion products decrease significantly, and ODNPS has the best effect. According to the analysis, the nano-sized aromatic carbon and silicon oxide produced by the pyrolysis and combustion of ONPS and ODNPS improve the burning rates of the propellants and inhibit the aluminum combustion agglomeration of the propellants.