Effect of surface coupling agents on the mechanical behaviour of polypropylene/silica composites: a molecular dynamics study

We investigate the mechanical behavior of polypropylene/silica composites under mode I and II loading by using molecular dynamics simulations, focusing on the effects of two typical surface coupling agents of HMDZ and APTES on the interface deformation and failure. It is found that under mode I loading, the silica surface functionalized with APTES can enhance the tensile strength of polypropylene/silica composites effectively. In contrast, the silica surface functionalized with HMDZ has little effect on the tensile strength. The simulation results are supported by experiments. Under mode II loading, it is found that both HMDZ and APTES can enhance the shear strength of polypropylene/silica composites with APTES being more effective. The underlying mechanisms for the enhancement of interface strength are analyzed. Our work provides a deep understanding of the interface structure, deformation and failure and will be useful for selecting suitable surface coupling agents in enhancing the interface strength of polymer composites.

Automated summary

The mechanical behavior of polypropylene/silica composites under mode I and II loading with two typical surface coupling agents, HMDZ and APTES, was investigated using molecular dynamics simulations. It was found that APTES enhanced the tensile strength effectively under mode I loading, while both HMDZ and APTES enhanced the shear strength under mode II loading, with APTES being more effective. The underlying mechanisms for the enhancement of interface strength were analyzed in the study, providing a deeper understanding for selecting suitable surface coupling agents to enhance the interface strength of polymer composites.