| In this paper, the nanoindentation tests on the two models of neat polyethylene (PE) and the polyethylene incorporated with 25 wt.% POSS (POSS-PE) are performed to reveal the reinforcing mechanism of the mechanical properties. The molecular mechanics method is adopted to eliminate the temperature effects. After the loading and unloading processes, the hardness and Young's modulus are calculated through the curve of loading versus displacement. Compared with PE, these mechanical properties of POSS-PE are improved dramatically. To interpret such enhancement effect, first we compare the average displacements of two models. The results show that the average displacement of POSS-PE is much smaller than that of PE, i.e., the deformation of PE is restrained by POSS unit. Utilizing the slipping models, we then analyze the relationship between loading drop phenomenon and slipping energy. From the simulation results, it is believed that the protrudent slipping energy is corresponding to the loading drop exactly, and the slipping between molecular chains is the main source of the loading drop. Furthermore, the average slipping energy of POSS-PE is smaller than that of PE, which implies that the slipping of PE is suppressed by POSS unit. |
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