Qualitative Characterization Of Interface Forces Between HMX And Binder

Polymer bonded explosive(PBX)has many advantages such as high energy density,good mechanical properties,easy forming and processing,low mechanical sensitivity.It is a multidirectional brittle heterogeneous material composed of simple explosive grains(such as HMX,RDX,TATB)as the main explosive and a small amount of polymer binder.Because it is a composite material composed of many kinds of materials,there must be a lot of interfaces in the composite material.If the interfacial force is not strong,problems such as cracks in the explosive crystal,particle fracture,interface debonding and interface cracking between the explosive crystal and the binder will be encountered.As a result,the density of PBX composite materials decreases,energy decreases,hot spots increase,and mechanical properties deteriorate.To solve this problem,this paper intends to use the force curve technology of atomic mechanics microscope(AFM),combined with the popular particle probe modification technology,to modify the explosive crystal on the probe,so as to study the interface interaction between the explosive crystal and the polymer.Its main contents are as follows:Firstly,contact angles of the four selected binders were measured by contact Angle instrument,and then surface energies of these four polymers were calculated by Owens and Wendt method,Finally,the adhesion work of 1,3,5,7-tetranitro-1,3,5,7-tetranazine cycloheteroctane(HMX)with these four polymers was calculated.The interaction between HMX and these four polymers was evaluated by the parameter of adhesion work.The final results indicate that the order of magnitude of HMX and its adhesion work is LBA-332>JM-01>LBA-06>F2314.Then,AFM was used to characterize the interaction force between HMX and these four polymers.It was found that the order of the interaction force was LBA-332>JM-01>LBA-06>F2314.It is preliminarily proved that AFM can be used to characterize the interaction force between explosive crystal and polymer.Secondly,AFM and contact Angle were used to explore polymer films under different film forming conditions(whether they are formed under vacuum,at different heat treatment times,and at different heat treatment temperatures),and to explore the influence of these conditions on the interfacial forces.The results of the two characterization methods showed that film forming in vacuum would reduce the interaction between the two phases.Increasing the heat treatment time within a certain time will reduce the interfacial interaction between polymer and HMX such as binder.In a certain heat treatment temperature range,the higher the heat treatment temperature,the interaction between HMX and the four polymers will be reduced.Finally,the relationship between the interfacial interaction force measured by AFM and the polymer used above,the coating effect and the thermal properties of the prepared composites were studied and analyzed.SEM data show that the greater the interaction force,the better the coating effect.The results of DSC showed that for the four polymers,the higher the interaction force with HMX,the lower the exothermic peak temperature.It is concluded that the interaction force between the polymer and HMX will affect the surface morphology and thermal properties of the prepared composites.It is inferred that it is also related to phase transition and sensitivity.