Simulation Study On Structure And Performance Of Polyimide/Potassium Tantalate Niobate Composite Material

In recent year, many researchers have been attracted to the polymernanocomposites that adopt inorganic nanoparticles for their extraordinary propertiesand broad application prospects. The structure and performance ofPolyimide/Potassium tantalate niobate (PI/KTN) composite material wereinvestigated using first-principles calculations and molecular dynamic simulations.The effect of potassium vacancies on the electronic structure and properties of KTN,and the effects of KTN nanoparticles with different doping ratio, size and shape onthe microstructure and performance of PI/KTN composite material were studiedrespectively.First of all, the modes of KTN and KTN with potassium vacancy wereconstructed, and the effects of potassium vacancy on the electronic structure andproperties were calculated and analyzed using first-principles. Then, the effects ofKTN nanoparticles with different shape on the interface bond energy in the PI/KTNnanocomposite were investigated using molecular dynamic simulations. Finally, theeffect of KTN with different size on the microstructure and mechanical properties ofPI/KTN nanocomposite were studied using molecular dynamics method, and thesmall size effect were analyzed through the calculation of the interface bond energyand the number of particles and surface atoms.The simulation results show that the displacement of Ta atoms is greater thanthe one of the Nb atom due to potassium vacancy occur, and the Nb-O bond isstronger than the Ta-O bond. The bond energy of particle surface atoms are2.058-12.988kcal/mol, which shows the binding force between particles and thematrix are mainly van der Waals force, and hydrogen bonds exist at the same time.At the same doping volume fraction, the bond energy of the sphere nanoclusters issignificantly larger than the ones of other shape nanoparticles (cube, cylinder andcone). The Young’s modulus of the PI and PI/KTa0.5Nb0.5O3composites are2.914 GPa and3.169GPa, and the Poisson’s ratio are0.370and0.353, which illustrate thatthe mechanical properties of the PI could be improved by the introduction of theKTa0.5Nb0.5O3nanoparticles. Besides, the proportion of nanoparticles surface atomsincrease significantly as the size decreases, the interaction between particles with thematrix becomes stronger, doping smaller size KTN nanoparticle into the polyimidematrix can significantly improve the mechanical properties of the polyimide.