The nanoparticle (NP) functionalization is an effective method for enhancing their compatibility with polymer which can influence the fracture property of the polymer nanocomposites (PNCs). This work aims to further understand the cavitation and crazing process, hoping to uncover the fracture mechanism on the molecular level. By adopting a coarse-grained molecular dynamics simulation, the fracture energy of PNCs first increases and then decreases with increasing the NP functionalization degree α while it shows a continuous increase with increasing the interaction ε_pA between polymer and modified beads. The bond orientation degree is first characterized which is referred to as the elongation. Meanwhile, the stress by polymer chains is gradually reduced with increasing the α or the ε_pA while that by NPs is enhanced. Furthermore, the percentage of stress by polymer chains first increases and then decreases with increasing the strain while that by NPs shows a contrast trend. Moreover, the number of voids is quantified which first increases and then decreases with increasing the strain which reflects their nucleation and coalescence process. The voids prefer to generate from the polymer-NP interface to the polymer matrix with increasing α or ε_pA. As a result, the number of voids first increases and then decreases with increasing α while it continuously declines with the ε_pA. In summary, our work provides a clear understanding on how the NP functionalization influences the cavitation and crazing process during the fracture process.

纳米粒子（NP）的功能化是一种有效的方法，可以增强它们与聚合物的相容性，这可以影响聚合物纳米复合材料（PNC）的断裂性能。这项工作旨在进一步了解空化和开裂过程，以期在分子水平上揭示断裂机理。通过采用粗粒分子动力学模拟，PNCS先增加断裂能，然后用增加NP官能度降低α，同时它示出了具有增加的相互作用连续增加ε _pA的聚合物和改性珠之间。首先表征键的取向度，这被称为伸长率。同时，随着聚合物链的增加，聚合物链的应力逐渐减小。α或ε _pA的同时，通过纳米颗粒被增强。此外，聚合物链的应力百分比首先随应变的增加而增加，然后减小，而NPs的应力百分比则显示出对比趋势。此外，对空洞的数量进行了量化，然后随着应变的增加而先增加然后减少，这反映了它们的形核和聚结过程。空隙倾向于从聚合物-NP接口与聚合物基质随产生α或ε _pA的。其结果是，空隙的第一增加，然后数目随着增加而减小α，同时它不断地与下降ε _pA的。总而言之，我们的工作使人们对NP功能化如何影响断裂过程中的气穴和开裂过程有了清晰的了解。