Akarsh Verma

Atomistic modeling of graphene/hexagonal boron nitride polymer nanocomposites: a review

Due to their exceptional properties, graphene and hexagonal boron nitride (h‐BN) nanofillers are emerging as potential candidates for reinforcing the polymer‐based nanocomposites. Graphene and h‐BN have comparable mechanical and thermal properties, whereas due to high band gap in h‐BN (~5 eV), have contrasting electrical conductivities. Atomistic modeling techniques are viable alternatives to the costly and time‐consuming experimental techniques, and are accurate enough to predict the mechanical properties, fracture toughness, and thermal conductivities of graphene and h‐BN‐based nanocomposites. Success of any atomistic model entirely depends on the type of interatomic potential used in simulations. This review article encompasses different types of interatomic potentials that can be used for the modeling of graphene, h‐BN, and corresponding nanocomposites, and further elaborates on developments and challenges associated with the classical mechanics‐based approach along with synergic effects of these nano reinforcements on host polymer matrix.

Molecular dynamics based simulations to study the fracture strength of monolayer graphene oxide

The aim of this article is to study the effects of functional groups such as hydroxyl, epoxide and carboxyl on the fracture toughness of graphene. These functional groups form the backbone of the intrinsic atomic structure of graphene oxide (GO). Molecular dynamics based simulations were performed in conjunction with reactive force field parameters to capture the Mode-I fracture toughness of functionalised graphene. Simulations were performed in stages, to study the effect of these functional groups, individually as well as all together on the fracture toughness of GO nanosheets. The molecular dynamics based simulations performed in this article helps us to conclude that the spatial distribution and concentration of functional groups significantly affects the fracture behavior of GO nanosheets.

Experimental investigation of chicken feather fiber and crumb rubber reformed epoxy resin hybrid composite: mechanical and microstructural characterization

Abstract In this experimental investigation, the mechanical characterization and microstructure study of chicken feather fiber (CFF) and crumb rubber filled epoxy resin hybrid composite has been done. The surface of the fibers was treated with sodium hydroxide to improve the interphase bonding. Chicken feathers were taken in different weight percentages of 1, 3, 5 and 7. A composite was fabricated with epoxy resin using the hand lay-up technique. After conducting various mechanical tests in accordance with the ASTM standards, it was observed that 5 wt% of CFF recorded the optimum results. Hybrid composites were then fabricated with 5 wt% CFF and varying weight percentages of crumb rubber, i.e. 0, 0.5, 1, 1.5, 2 and 2.5. On the basis of mechanical testing conducted on hybrid composite, tensile strength, flexural strength and impact strength showed a significant improvement. The justification of trend was given through the microstructural tests, which were a scanning electron microscopy (SEM) and X-ray diffraction analysis. It was concluded that 1 wt% of crumb rubber with 5 wt% CFF hybrid composites showed the optimum results amongst various combinations. Thus, properties showed significant improvement in the case of hybrid composite as compared to pure fiber-based composite.

Tailoring the failure morphology of 2D bicrystalline graphene oxide

The aim of this article is to study the effect of oxide functionalisation on the failure morphology of bicrystalline graphene. Molecular dynamics based simulations in conjunction with reactive force field were performed to study the mechanical properties as well as failure morphology of different configurations of bicrystalline graphene oxide. Separate simulations were performed with hydroxyl and epoxide functionalisation, and later on the same simulations were extended to study the graphene oxide as a whole. The authors have predicted that epoxide functionalisation helps in transforming the catastrophic brittle behaviour into ductile. Failure morphologies depict that epoxide groups tend to boost the ductility through altering the fracture path and not affecting the grain boundaries either. Also, the epoxide to ether transformations were found to be the decisive mechanism behind the plastic response shown by epoxide groups. Simulations help in concluding a ductile failure for bicrystalline graphene in conjunction with oxidation of selective atoms in the nanosheet, which further opens new avenues for the application of these graphene sheets in nanodevices and nanocomposites.The aim of this article is to study the effect of oxide functionalisation on the failure morphology of bicrystalline graphene. Molecular dynamics based simulations in conjunction with reactive force field were performed to study the mechanical properties as well as failure morphology of different configurations of bicrystalline graphene oxide. Separate simulations were performed with hydroxyl and epoxide functionalisation, and later on the same simulations were extended to study the graphene oxide as a whole. The authors have predicted that epoxide functionalisation helps in transforming the catastrophic brittle behaviour into ductile. Failure morphologies depict that epoxide groups tend to boost the ductility through altering the fracture path and not affecting the grain boundaries either. Also, the epoxide to ether transformations were found to be the decisive mechanism behind the plastic response shown by epoxide groups. Simulations help in concluding a ductile failure for bicrystalline graphene in con...

Mechanical Properties and Microstructure of Starch and Sisal Fiber Biocomposite Modified with Epoxy Resin

In this experimental analysis, fabrication and characterization of biocomposites derived from starch-glycerol resin and sisal fiber have been done using the wet hand lay-up technique. Fibers having different weight percentage and 2–3-mm length have been taken for the investigation. The surface of fibers was treated with sodium hydroxide (NaOH) to improve the interphase bonding. The mechanical tests of composites were investigated in accordance with ASTM standards. Various other tests that were conducted include water absorption, thermal analysis, and scanning electron microscopy (SEM). The main drawback of natural composite is its poor water absorption property, which has been checked here by the epoxy coating. The results of the tests reveal a significant improvement in overall properties of biocomposite when compared with the neat starch matrix.