| 초록 |
In this study, single-step branched polyethyleneimine (PEI)-assisted exfoliation of molybdenum sulfide nanosheets (MoS2¬-PEI) was carried out. These functionalized MoS2-PEI nanosheets were employed as toughening agents for epoxy composites. The loadings of nanosheets were kept lower than 1 wt.%. The mechanical and thermal properties, and interfacial interactions of epoxy composites were investigated. The epoxy composites shown ~67% and ~101% enhancements in fracture toughness (KIC) and in fracture energy (GIC) at nanosheets loadings as small as 0.09 wt.% (EP/MoS2-PEI-0.09), KIC shows direct linear relationship with the surface free energy and is highest at 52 mJ.m−2 for the EP/MoS2-PEI-0.09 composite. However, the surface free energy values of EP/MoS2-PEI-0.16 and EP/MoS2-PEI-1 composites decreased to 48 mJ.m-2 and 45 mJ.m−2. The overall flexural modulus (E) and strength (σ) were not highly responsive to the addition of the MoS2-PEI nanosheets. |
