Mostafa Nikzad

Two- and three-dimensional graphene-based hybrid composites for advanced energy storage and conversion devices

Due to its superior electronic, thermal, and mechanical properties, graphene is considered to be the most promising candidate for constructing energy storage and conversion devices. One important way to exploit the potential of graphene is to create graphene composites with other functional materials. Graphene-based hybrid composites (GHCs) have been fabricated by incorporating inorganic and/or organic species into graphene through covalent and/or noncovalent interactions. Different methods of fabrication resulted in different properties of GHCs. So far, GHCs have found wide applications in various sectors. In this article, recent progress and achievements in the preparation of two- and three-dimensional GHCs are reviewed, followed by detailed discussions on their physical, chemical, and mechanical properties. The article then focuses on the detailed applications of GHCs in energy storage and conversion devices.

Rheological Properties of a Particulate-Filled Polymeric Composite through Fused Deposition Process

This paper presents an investigation on rheological properties of a new ABS (acrylonitrile-butadiene-styrene)-Iron composite for application in Fused Deposition Modelling rapid prototyping process. Test samples of ABS-Iron composites have been made by controlled centrifugal mixing and thermal compounding through a single-screw extruder and compression moulding. Rheological characterization was conducted using a capillary rheometer by measuring pressure drop at the die while varying the extrusion speed. Apparent shear rate and shear stress as well as viscosity of the melts were calculated. Modulated differential-scanning calorimetry (MDSC) techniques were used in order to characterize viscoelastic properties of these newly developed composites materials. Non-Newtonian behaviour of the composite melt has shown to follow a cross model of shear thinning characteristics.

In-plane energy absorption evaluation of 3D printed polymeric honeycombs

ABSTRACT Honeycomb structures have been widely used for impact protection and energy absorption applications. However, studies on such structures have been mainly limited to metallic honeycombs with little research done on polymeric honeycomb structures. The purpose of this paper is to study the in-plane static compressive crushing behaviour and energy absorption capacity of 3D printed polymeric honeycomb structures of different unit cell thicknesses. Uniaxial quasi-static compression tests were performed on hexagonal honeycomb structures of varying wall thicknesses printed in Nylon 12 by fused deposition modelling 3D printing. Numerical simulations using ABAQUS/Explicit finite element analysis software were performed to determine the compressive behaviour of the same honeycomb structures. Gibson and Ashby’s analytical model was also used to determine the theoretical plateau stresses of the honeycombs. The experimental compressive behaviour, plateau stress and energy absorption capacity of the honeycombs were compared with numerical and analytical values. It was found that experimental results obtained are in good agreement with computational numerical solutions and with the theoretical model for all cell wall thickness to cell wall length ratios. It was also observed that the plastic deformation of hexagonal honeycombs are different in its two main in-plane directions and 3D printing can be applied to generate honeycomb structures of varying geometry and energy absorption capacity with predictable performance.

An Investigation of Mechanical Properties of Recycled EVA/Commingled Plastics

In the present study, the mechanical properties of recycled ethylene-vinyl acetate (EVA)/commingled thermoplastic polymer (CTP) composite material are investigated. The recycled CTP was blended with recycled EVA at different fractions by weight to form CTP/EVA composites.Test specimens of CTP/EVA composites were produced using compression moulding process to evaluate their mechanical properties. The results of tensile testing showed that the incorporation of EVA into CTP resulted in reduction of tensile strength but increase in elongation at break. In addition, the impact testing and flexural testing also showed that there is a general decrease in impact and flexural strength and also in flexural deformation, with increased percentage of EVA into the composite materials.