Molecular dynamics simulation study on the structure and properties of polyimide/silica hybrid materials

ABSTRACT A type of polyimide/silica (PI/SiO 2 ) copolymer model was established through the dehydration of tetraethyl orthosilicate molecules (TEOS) and bonding to a silane coupling agent. The content of SiO 2 was controlled by adjusting the number of molecules which bound to the TEOS. Finally, the silica was formed into a hybrid model (hybrid PI/SiO 2 ) with a small molecule embedded in the PI. The model was optimized by geometric and molecular dynamics and the changes in the model structure, Young's modulus, shear modulus, and glass‐transition temperature ( T g ) were analyzed. The results showed that the density and cohesive energy density of the composites could be improved by doping SiO 2 in PI. Young's modulus and shear modulus of PI/SiO 2 hybrid materials were higher than undoped PI. The tensile strength reached 568.15 MPa when the doping content was 9%. Therefore, the structure design and content control of SiO 2 was an effective way to improve the performance of a PI/SiO 2 composite. The variation of T g and tensile strength of PI/SiO 2 hybrid composites is consistent with that of PI/SiO 2 composite synthesized in real experiment, which will be a convenient method for new material design and performance prediction. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47335.