改性纳米粒子增强聚合物基复合材料力学性能的分子动力学模拟研究-工程力学专业论文.docxVIP

暨南大 暨南大学硕士学位论文 II II III III Abstract At present, nanoparticle reinforced polymer matrix composite is one of the research emphasis in the field of nanometer materials science. With the excellent properties of nanoparticles and polymer, it is widely applied in many fields. Because nanoparticles have many surface atoms, highly active and with many broken keys, easily agglomerated, the nano size effect cannot act effectively. The experimental results of many researchers show that the nanoparticle surface treatment can effectively improve the properties of composite. With the development of computer technology, molecular simulation software as a supplement of the experiment can predict the influence factor in qualitative and quantitative analysis, providing more intuitive results for analysis and further guide for experiments. Effective moduli of fiber-reinforced polymer matrix composites filled with nanoparticle considering the effect of linear change of interphase are presented in this paper based on the Mori-Tanaka method. The formula to calculate the elastic modulus and Poisson’s ratio are derived and effects of the thickness of interfacial layer, the particle size and the volume fraction of nanoparticles on the effective elastic moduli of the composites are also discussed. According to the molecular dynamics theory, the molecular model of SiO2 and polyimide (PI) can be built by the Materials Studio software and make the following analysis: SiO2/PI composite model is established, the mechanical properties are calculated, and the Youngs modulus and Poissons ratio of the unit cell are obtained，effects of the particle size and the volume fraction on the mechanical properties of the composites are discussed. The results show that nanoparticle can improve the mechanical properties of composites in some extent compared with pure polyimide. In the Materials Studio software, the SiO2nanoparticles are treated in three ways: silicon proply modified, directly and covalently gr