Sharif Digital Repository

Nowadays, the significance of sustainability has urged composite manufacturers to replace traditional synthetic fibers with eco-friendly natural alternatives due to their environmental and economic benefits. This work aims to fabricate hybrid polypropylene (PP) composites with short flax fibers, octene-ethylene copolymer (POE) rubber particles, and maleic anhydride-grafted polypropylene (MAPP) compatibilizer. The main goal is to gain an insight into the combined effect of toughening mechanisms induced by the short fibers and rubber particles at the crack tip and wake of composites, which is a crucial step in reaching a balance between toughness and rigidity. In this regard, a novel... 

Material properties and fracture characteristics are among the most prominent parameters that should be considered for a wide range of graphene applications. This article reviews recent advances in theoretical studies on the mechanical properties and fracture behaviors of graphene, focusing on the effect of various simulation models. Most studies investigated single-layer graphene sheets (SLGSs) under uniaxial tensile tests using different common interatomic potentials, particularly AIREBO. Although researchers have examined a similar problem, specifically for pristine graphene, the differences in the reported values are considerable. These discrepancies are most evident in fracture... 

Hydrogels with remarkable hydrophilicity and tunable toughness are appealing materials to serve as superabsorbent polymers. However, chemically cross-linked hydrogels often suffer from low toughness regardless of their considerable swelling, restricting their widespread applications. In comparison, the network of physically cross-linked hydrogels can be regulated to meet both a high swelling ratio and considerable toughness. Here, we develop superabsorbent and tough hydrophobic associated hydrogels using terpolymerization of poly acrylic acid (PAA), polyacrylamide (PAM), and lauryl methacrylate (LMA) within the micelles formed by sodium dodecyl sulfate (SDS) surfactant. To this end, various... 

Abstract: Bead-on-plate submerged arc welding was conducted on St37 steel by manufactured Cr, Mo, and Cr–Mo active basic fluxes produced via the unfused bonded method. The base metal heat-affected zone and weld metal (WM) microstructures were identified and characterized by optical microscopy and scanning electron microscopy. Furthermore, each element’s recovery rate (η) and slag factor (α) determine the amount of element transferred from flux into WM. Then, the ferrite morphologies volume fraction of WMs was measured. Moreover, the chemical analysis of slag and inclusions was evaluated by point scan energy-dispersive X-ray spectroscopy and extensively discussed. The number density and... 

Nature-inspired coating with polydopamine (PDA) is a promising way to improve the performance of graphene oxide (GO) based nanocomposites due to its high ability to enhance interactions in matrix-disperse systems. Here, we examined the capability of two types of PDA to develop the reinforced polyvinyl alcohol (PVA)/GO hydrogels. In the first mode, dopamine hydrochloride was polymerized as nanoparticles and then incorporated into PVA solution with GO nanoplatelets (P-NG hydrogel). In the second mode, polydopamine was polymerized in the presence of GO nanoparticles to obtain PDA surface-modified GO and then PVA nanocomposite hydrogel (P-CG sample). Rheological and tensile findings revealed...