Mechanical properties of nanocomposites with functionalized graphene

Abstract

The research investigated the thermal and mechanical properties of graphene/epoxy nanocomposites. Pristine graphene and functionalized graphene were used as nano-reinforcement in the nanocomposites. The graphene loadings employed in the nanocomposites were 0.1, 0.3, 0.5, and 1.0 wt%. The functional groups grafted on the functionalized graphene were characterized through Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Results indicated that two kinds of functional groups are grafted on the functionalized graphene surfaces: one contains only COOH group and the other contains both COOH and NH2 groups. Moreover, from mechanical and thermal testing, it was found that the nanocomposites with functionalized graphene demonstrate better mechanical and thermal properties than those with pristine graphene. The graphene containing NH2 and COOH functional groups exhibits superior mechanical and thermal properties than the graphene with only COOH functional group. In addition, Young’s modulus and thermal conductivity of the nanocomposites increase as the graphene loading increases. However, the fracture toughness and tensile strength of the nanocomposites attain peak values when the functionalized graphene loading is 0.1 wt%. The effects of the functional groups on the mechanical and thermal properties of nanocomposites were elaborated using molecular dynamics (MD) simulation. It was revealed that the interfacial thermal conductance and normalized interaction energy increase between the functionalized graphene and epoxy matrix, which may be responsible for the enhanced mechanical properties in the functionalized graphene/epoxy nanocomposites.

On the mechanical behavior of basalt fiber/epoxy composites filled with silanized graphene oxide nanoplatelets

“…The aggregation of graphene in polymeric matrix is a key problem in nanocomposite preparation . It hinders the effective stress transfer to each individual graphene and consequently reduces the mechanical properties of resultant specimen .…”

“…A number of studies have conducted on developing effective methods for homogeneous dispersion of graphene in polymer matrix and improving the graphene‐matrix interfacial strength. Surface modification of graphene with coupling agents is one of these methods . Coupling agents have two different functional groups in their specific structures, one side fits with polymeric matrix and other is bonded to functional groups on the surface of graphene .…”

Characteristics and mechanical properties of composites based on nitrile butadiene rubber using graphene nanoplatelets

“…Using 1 mass.% functionalized graphene (−COOH and −NH 2 groups), the authors managed to increase thermal conductivity by 43%, tensile modulus by 18%, and Young's modulus by 15% compared with the original epoxy rubber. 17,18 Asadollahi-yazdi 19 at using 2.4 mass.% graphene were able to increase the tensile strength compared with the original polyoxymethylene by 64% and Young's modulus compared with the initial polyoxymethylene by 103%. Atif 20 demonstrates that the influence of multilayered nanostructured graphene as reinforcement on thermal and mechanical properties of epoxy-based nanocomposites has been studied.…”

Tensile behavior of polymer nanocomposite reinforced with graphene containing defects

“…To validate the present MD model, Table 1 compares our result for the Young's modulus of perfect graphene reinforced epoxy nanocomposite and the experimental data [10,30] for epoxy nanocomposite reinforced with perfect graphene, functionalized graphene, and…”

“…Reasonably good agreement is achieved. Young's Modulus (GPa) Matrix Nanocomposite Graphene/epoxy [30] 1% Experiment 3.24 3.55 COOH graphene/epoxy [30] 1% Experiment 3.24 3.60 COOH+NH2 graphene/epoxy [30] 1% Experiment 3.24 3.66 GPL/epoxy [10] 0.1% Experiment 2.85 3.74 Graphene/epoxy [present] 0.88% MD Method 2.74 4.68 Fig. 3a that the Young's modulus in zigzag direction is slightly higher than that in armchair direction and that the modulus decreases with more missing atoms in both single-and double-vacancy defects but the reduction differs with the loading direction and defect type.…”