Sharif Digital Repository

In this paper, we review recent progress made in the field of epoxy-based binary and ternary nanocomposites containing three-, two-, and one-dimensional (i.e., 3D-, 2D-, and 1D) nano-size fillers with a special focus on their fracture behaviors. Despite investigations conducted so far to evaluate the crack-resistance of epoxy nanocomposites and attempts made to clarify the controlling toughening mechanisms of these materials, some questions remain unsolved. It is shown that silica nanoparticles can be as effective as rubber particles in improving the fracture toughness/energy; but incorporation of carbon nanotubes (CNTs) or clay platelets in epoxy matrices delays crack growth only modestly.... 

Polyolefin blends have attracted great attention for years because of their improved physical and mechanical properties; especially when micro/nanofillers are present in the compound. Previous investigations have proven that incorporation of small amounts of nanoclay can enhance physical and mechanical properties of the polymer. This research has focused on the role of clay distribution on morphology and mechanical properties of ternary nanocomposites containing a rubbery phase. High-density polyethylene/ethylene vinyl acetate/clay (HDPE/EVA/clay) is opted as a typical model for this purpose. EVA is selected to act as both compatibilizer, because of having polar vinyl groups, and... 

The development of asymmetric supercapacitors requires the design of electrode construction and the utilization of new electroactive materials. In this regard, an effective strategy is the loading of active materials on an integrated 3D porous graphene-based substrate such as graphene foam (GF). Herein, we successfully designed and fabricated a novel ternary binder-free nanocomposite consisting of polypyrrole, Fe-Co sulfide, and reduced graphene oxide on a nickel foam electrode (PPy/FeCoS-rGO/NF) via a facile, cost-effective, and powerful electrodeposition method for application in high-performance asymmetric supercapacitors. The monolithic 3D porous graphene foam (GF) obtained by the facile... 

In this research, polyaniline@Ba0.5Sr0.5Fe12O19@MWCNTs nanocomposite was prepared via co-precipitation and in-situ polymerization methods, respectively. Microstructural, magnetic and electromagnetic wave absorption analysis of the prepared nanocomposite were studied via XRD, FESEM, VSM and VNA. Compared with Ba0.5Sr0.5Fe12O19@MWCNTs, the microwave absorption bandwidth of the coated nanocompoite with polyaniline was significantly enhanced, which increased to approxiamately 4 GHz from 3 GHz. The effective microwave absorption performance of the Ba0.5Sr0.5Fe12O19@MWCNTs nanocomposite was attributed to increase in the interfacial polarization, improvement in impedance matching as well as porous... 

A new ternary nanocomposite based on graphene oxide (GO), polypyrrole (PPy) and vanadium pentoxide (V2O5) is obtained via one-step electrochemical deposition process. Electrochemical deposition of V2O5, PPy and GO on a stainless steel (SS) substrate is conducted from an aqueous solution containing vanadyl acetate, pyrrole and GO to get V2O5/PPy/GO nanocomposite. Characterization of the electrode material is carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). The electrochemical performance of the as-prepared nanocomposite is evaluated by... 

The objective of this study was to investigate the effects of two compatibilizers, namely maleated polypropylene (PP-g-MA) and maleic anhydride grafted poly (ethylene-co-octene) (EOC-g-MA), on the morphology and thus properties of ternary nanocomposites of polypropylene (PP)/ethylene-octene copolymer (EOC)/clay nanocomposite. In this regard the nanocomposites and their neat polymer blend counterparts were processed twice using a twin screw extruder. X-ray diffraction, transmission electron microscopy, Energy dispersive X-ray spectroscopy, and scanning electron microscopy were utilized to characterize nanostructure and microstructure besides mechanical and rheological behaviors of the... 

Ternary nanocomposites of polypropylene/polyamide 6/layered silicate were prepared through three different processing procedures. X-ray diffraction and transmission electron microscopy were used to study the nanostructure of the samples, and tensile and impact strength measurements were conducted to assess the mechanical properties. It was shown that processing route has a significant effect on the delamination of clay platelets. Fully exfoliated nanostructure was achieved through a certain two-step processing route. Compatibilization of the blends affected microstructure as well as nanostructure. Mechanical properties were affected by changing the processing route, to a great degree.... 

Attempts were made to trace the effect of organoclay (OC) on the rheological and mechanical behaviors of the low density polyethylene (LDPE)/ethylene-vinyl acetate (EVA) blends. To do this effectively, in addition to LDPE/EVA/OC system, pure LDPE and LDPE/EVA blends were also examined as model systems. The rheological behavior was determined by the capillary rheometer. Morphological characterization was also carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and theoretical approach based on interfacial energies. Shear viscosity, tensile strength and elastic modulus of LDPE/EVA were found to decrease by increasing the EVA... 

Abstract: Au nanoparticles supported on cerium oxide/graphitic carbon nitride (CeO2@g-C3N4) was synthesized and used as heterogeneous catalyst in redox reaction. The catalyst was characterized by different techniques such as FT-IR, XRD, FE-SEM, EDS, TEM, BET, TGA, and ICP. The as-prepared ternary nanocomposite was used as an effective catalyst for the reduction of toxic 4-nitrophenol to useful 4-aminophenol by NaBH4. The rate constant value of reduction reaction reached up to 0.106 s−1 by Au/CeO2@g-C3N4, which was 3.8, and 8.8 times higher than that of Au@CeO2 (0.028 s−1), and Au@g-C3N4 (0.012 s−1) nanocomposites, respectively. The superior catalytic performance of as-prepared catalyst in... 

Density functional theory (DFT) calculations have been performed to investigate the electronic structure and photocatalytic activity of a hybrid Ag3PO4(111)/g-C3N4 structure. Due to Ag(d) and O(p) states forming the upper part of the valence band and C(p), N(p), and Ag(s) the lower part of the conduction band, the band gap of the hybrid material is reduced from 2.75 eV for Ag3PO4(111) and 3.13 eV for monolayer of g-C3N4 to about 2.52 eV, enhancing the photocatalytic activity of the Ag3PO4(111) surface and g-C3N4 sheet in the visible region. We have also investigated possible reaction pathways for photocatalytic CO2 reduction on the Ag3PO4(111)/g-C3N4 nanocomposite to determine the most... 

A novel binary BiOI/ZnFe2O4 (BZ) with p-n heterojunction based on the different metal-organic framework (MOF) MIL-88B(Fe) and graphite carbon nitride (g-C3N4) as substrates has been designed. As-prepared ternary nanocomposites have been first obtained via a simple hydrothermal system and subsequently deposited onto the MOF and g-C3N4 substrates. The photoactivity of the ternary nanocomposites was evaluated by organic pollutants degradation under LED light. These characterization results indicated that BiOI as a p-type semiconductor was well deposited on the surface of ZnFe2O4 (n-type semiconductors). The p-n heterojunction photocatalyst (BZ) improved the valence band potential of ZnFe2O4 and... 

The development of active and stable materials has great importance for the commercialization of nickel-zinc (Ni–Zn) batteries and hydrogen production. Transition metal sulfides have good theoretical properties for these applications. In this research, we present the synthesis and characterization of Ni3S2@MoS2 nanocatalyst and its hybrid with reduced graphene oxide (Ni3S2@MoS2-rGO). The capability of these materials is investigated as cathode material for Ni–Zn batteries and hydrogen evolution in alkaline media. In the case of Ni–Zn batteries, the assembled Ni3S2@MoS2-rGO//Zn battery shows a discharge capacity of 249.3 mAh g−1 with coulombic efficiency of 97.2%, showing a higher... 

The present study deals with the structure-property relationship of organoclay (OC) filled nanocomposites based on rubber blend comprising of nitrile-butadiene rubber (NBR) and phenolic resin (PH). To obtain a better insight into the characteristics of the NBR/PH/OC hybrid system, a simple model system consisting of NBR/OC nanocomposites is also taken into consideration. A series of NBR/OC and NBR/PH/OC nanocomposites containing a wide range of OC concentrations (2.5-30 phr) are prepared by using traditional open two-roll mill. Structural analysis performed by X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) exhibits mixed exfoliated and... 

This work aims to investigate the structure-property relationship in ternary nanocomposites consisting of polypropylene as the matrix, nanoclay as the reinforcement and polyamide 6 as the intermediate phase. In this regard, composites of polypropylene/organoclay, polyamide/organoclay, blends of polypropylene/polyamide, and ternary nanocomposites of polypropylene/polyamide/layered silicate with and without compatibilizer were produced via melt compounding. Nanostructure was investigated by wide-angle X-ray diffraction and transmission electron microscopy. Scanning electron microscopy was employed to study the microstructure. Modulus of elasticity and yield strength were measured by uniaxial...