دانلود رایگان مقاله رفتار مکانیکی و خواص اتصال هیدروژنی گرافن / رابط پلیمر نانو

Abstract

There is increasing evidence in literature for significant improvements in both toughness and strength of graphene-based nanocomposites through engineering their nano-interfaces with hydrogen bonds (H-bonds). However, the underlying mechanical behaviors and properties of these H-bonded interfaces at the microscopic level were still not experimentally clarified and evaluated. Herein, this work reports a study on the interfacial stress transfer between a monolayer graphene and a commonly used poly(methyl methacrylate) (PMMA) matrix under pristine vdW and modified H-bonding interactions. A nonlinear shear-lag model considering friction beyond linear bonding was proposed to understand evolution of interfacial stresses and further identify key interfacial parameters (such as interfacial stiffness, strength, frictional stress and adhesion energy) with the aid of in situ Raman spectroscopy and atomic force microscopy. The present study can provide fundamental insight into the reinforcing mechanism and unique mechanical behavior of chemically modified graphene nano-interfaces and develop further a basis for interfacial optimal design of graphene-based high-performance nanocomposites.

Conclusion

Based on the in situ Raman measurements and nonlinear shearlag model, we study the stress transfer of hydrogen bonded graphene/PMMA nano-interface. A nonlinear shear-lag model and corresponding analytical solutions were presented to understand evolution of interfacial (shear) stresses along the interface. Our nonlinear model might be also valid for graphene nano-interfaces with various types of interfacial interactions. The quantified interfacial parameters (stiffness, strength, frictional stress and toughness) for H-bonded interface can be substituted into micromechanical models to give the relationship between more complicated structures and overall properties of bulk composites. Implications for optimal design of graphene-based high-performance nanocomposites through tuning their nano-interfaces with hydrogen bonds were further summarized. Also, the understanding of the mechanical behavior and properties of H-bonded graphene/ polymer interface here could be useful in developing a basis for interfacial optimal design of high-performance graphene-based nanocomposites.