Molecular Dynamics Simulation Study On The CL-20/TNT Cocrystal And Its Composite System With Green Binder

In this paper,molecular dynamics(MD)simulation theory was used to study the green binder polylactic acid(PLA),polycaprolactone(PCL),polylactic acid-caprolactone copolymer(P(LA-co-CL)),polyethylene furandicarboxylate(PEF),poly(y-butyrolactone)(PyBL)and CL-20/TNT energetic cocrystal and their composite materials.The melting point of the CL-20/TNT energetic cocrystal was simulation calculated by the volume-temperature method,and the influence of the temperature gradient and the equilibrium time on the melting point was compared.When the temperature gradient is 15K and the equilibrium time is 200ps,the calculated melting point is 429K,and the relative error from the experimental value of 409K is 4.9%,the result is better;and prolonging the equilibration time has no significant effect on the calculated melting point.The density and glass transition temperatures of PLA,PCL,P(LA-co-CL),PEF and PyBL were calculated,the calculated densities of PLA,PCL and PEF were 1.17 g/cm3,1.11 g/cm3 and 1.35 g/cm3,respectively,with relative errors of 5.6%,3.5%and 6.3%with corresponding experimental values of 1.24 g/cm3,1.15 g/cm3 and 1.44 g/cm3,and predicted the density of P(LA-co-CL)and PyBL.At the same time,the simulation values of the glass transition temperature of the five polymers were 59℃,-57℃,-15℃,87℃ and-55℃,respectively,the corresponding experimental values were 55～60℃,-60℃,-15℃,87℃ and-52～-42℃,the simulation values of PLA are in the range of experimental values,the relative errors of the other polymers with the experimental values are 5.0%,0%,0%and 5.8%,it is good,further illustrates the COMPASS force field parameters of the applicability of the above polymer.The PLA、PCL、P(LA-co-CL)、PEF and PyBL with CL-20/TNT energetic cocrystal composite systems were calculated by MD simulation.The above five polymer binders’adhesion properties were compared on the four surfaces(0 0 1),(1 0 0),(0 1 0)H and(0 1 0)T of CL-20/TNT cocrystal.According to the interfacial tension,adhesion work and spreading coefficient,it is found that the five polymer binders and all have certain wetting and spreading ability on the four surfaces of cocrystal.However,all polymer binders have the lowest interfacial tension on the(0 0 1)plane of cocrystal,mainly due to the maximum spreading coefficient of the polymer binder on this plane.