Study On The Processing And Application Of GAP Modified Single Base Spherical Propellant

In order to improve the energy performance of single-base spherical propellant,the energy-containing binder polyazide glycidyl azide polymer?GAP?was added into the single-base spherical propellant by internal solution method to obtain the GAP modified single-base spherical propellant.The influence of various process parameters on the rotundness,particle size and density of the spherical propellant was explored.Butyl-nitroxyethyl nitramine?BuNENA?is used as a plasticizer,isophorone diisocyanate?IPDI?and dipropynyl succinate?BPS?are used as curing agents.GAP modified spherical propellant film was prepared by the polyurethane reaction and the 1,3-dipolar cycloaddition reaction,respectively.The isocyanate reaction system?polyurethane reaction?curing parameters R_IPDIPDI and non-isocyanate reaction system?1,3-dipolar cycloaddition?curing parameters R_BPSPS were studied in the double-curing system.And the influence of different solid additives?graphene,carbon fiber and activated carbon fiber?on film properties were explored.The effect of process parameters on the density of GAP spherical propellant was studied by the density bottle method.It was found that when the nitrocellulose nitrogen content,the dehydrating agent content,the amount of pre-exclude solvent and the formed temperature of the GAP spherical propellant increased,the density of the spherical propellant increased.When the GAP content increased,the density of the spherical propellant decreased.The particle size of the spherical propellant was studied.It was found that the concentration of surfactant,the amount of pre-exclude solvent and the formed temperature of the spherical propellant increased,and the particle size of the spherical propellant decreased.The morphology of the spherical propellant was studied by electron microscopy.As the nitrocellulose nitrogen content increased,there were more irregular particles;the GAP content increased,the surface of the spherical propellant turned rougher,and the optimal forming temperature for spherical propellant is 60°C.The GAP modified film was characterized by infrared spectrometer.It was found that the polyurethane and 1,3-dipolar cycloaddition reaction occurred in this GAP modified film.The thermal decomposition properties of this film were studied by differential scanning calorimetry?DSC?method.The results showed that the peak temperature of different formula films was about 20°C lower than that of C#NC.With the R_IPDI increased,the apparent activation energy?E_a?and the pre-exponential factor?A?decreased first and then increased.With the R_BPSPS increased,E_a and A increased first and then decreased.The static tension test showed that when the R_IPDI=1,the maximum tension strength?_max of the sample increased with the R_BPSPS increased.When R_BPS=0,the maximum elongation?_max of the films reached the maximum value?173%?.And when R_BPS=0.5,the?_max was the lowest value?15.24%?;When R_BPS=1,as the R_IPDI increased,the value of?_max for the films decreased.When R_IPDI=0.5,?_max reached the maximum value?22.59%?,and when R_IPDI=1.25,?_max got the lowest value?19.71%?.When solied additives,such as graphene,carbon fiber and activated carbon fiber,were added into the GAP modified film,the tension strength of the film can be greatly improved,but the value of elongation is lower.The tested results of linear thermal expansion coefficient showed that when R_IPDI=1,the linear thermal expansion coefficient of film decreased with R_BPS increased;when R_BPS=1,the linear thermal expansion coefficient of this film increases slightly with the R_IPDI increased.When activated carbon fiber,carbon fiber and graphene were added into the samples,the change of linear thermal expansion coefficient was unconspicuous.