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Mojtaba Ahmadi

Bio: Mojtaba Ahmadi is an academic researcher from Deakin University. The author has contributed to research in topics: Epoxy & Ultimate tensile strength. The author has an hindex of 17, co-authored 32 publications receiving 969 citations. Previous affiliations of Mojtaba Ahmadi include Isfahan University of Technology & Razi University.

Papers
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Journal ArticleDOI
TL;DR: In this article, a survey of the literature on structure-property relationships in epoxy-clay nanocomposites is presented, where various pivotal parameters affecting structures and properties of the nanocom composites including various types of modification as well as a vast range of available dispersion techniques are discussed.
Abstract: The review presents a survey of the literature on structure–property relationships in epoxy-clay nanocomposites. Herein, various pivotal parameters affecting structures and properties of the nanocomposites including various types of modification as well as a vast range of available dispersion techniques were discussed. Opportunities and challenges in regards to potential applications of nanoclay in multi-scale composites have been also addressed. The multi-scale composites containing nanoclays have been reviewed in terms of mechanical properties in both out-of-plane and in-plane directions, and compared with those containing carbon based nanofillers. In this regards, the improving mechanisms in mechanical properties of both epoxy-clay nanocomposites and nanoclay filled fiber reinforced composites were also discussed.

189 citations

Journal ArticleDOI
TL;DR: It was hypothesized that the use of Tinuvin 1130, as an organic UV absorber in the epoxy-amine system, could decrease the undesirable effects, arising from exposure to UV light.
Abstract: Despite several excellent properties including low shrinkage, good chemical resistance, curable at low temperatures and the absence of byproducts or volatiles, epoxy resins are susceptible to ultra violet (UV) damage and their durability is reduced substantially when exposed to outdoor environments. To overcome this drawback, UV absorbers have been usually used to decrease the rate of UV degradation. In this present study, the effects of UV light on the chemical, mechanical and physical properties of cured epoxy structure, as well as the effect of an organic UV absorber, Tinuvin 1130, on the epoxy properties were investigated. Chemical changes in a cured epoxy system as a result of the presence and absence of Tinuvin 1130 were determined using Fourier transform infrared spectroscopy (FT-IR) analyses. The effect of Tinuvin 1130 on the surface morphology of the epoxy systems was also investigated by scanning electron microscopy (SEM) imaging. Additionally, the glass transition temperatures (Tg) before and during UV radiation were measured. After an 800 h UV radiation, mechanical test results revealed that the lack of the UV absorber can lead to a ~30% reduction in tensile strength. However, in the presence of Tinuvin 1130, the tensile strength was reduced only by ~11%. It was hypothesized that the use of Tinuvin 1130, as an organic UV absorber in the epoxy-amine system, could decrease the undesirable effects, arising from exposure to UV light.

126 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used a prepared calcium nitrate solution as an inorganic accelerator to accelerate the curing reaction of bio-based epoxy resin which reduced curing times as well as improving significantly the mechanical properties e.g., tensile strength, pull-off strength, and Izod impact strength.
Abstract: The aim of this study is to find a suitable substitution for diglycidyl ether bisphenol A (DGEBA) to avoid the devastating side effects of bisphenol A. Vanillin, an aromatic compound, was used as a renewable material to synthesize a bio-based epoxy resin. The structure of the vanillin-based epoxy resin was confirmed by Fourier transform infrared spectroscopy (FT-IR) analysis. The major drawback of bio-based epoxy resins is their poor mechanical properties preventing them from competing with petroleum based epoxy resins such as DGEBA. Herein, a prepared calcium nitrate solution as an inorganic accelerator was used to accelerate the curing reaction of bio-based epoxy resin which reduced curing times as well as improving significantly the mechanical properties e.g., tensile strength, pull-off strength, and Izod impact strength. Differential scanning calorimetry (DSC) analysis was used to investigate the curing process and thermal properties of the vanillin-based epoxy resin with and without inorganic accelerators and also DGEBA without accelerators. The results showed that in the presence of 2 wt% inorganic accelerator, the initial onset curing temperature of vanillin-based epoxy resin was reduced from 60.1 °C to 8.5 °C, while the initial onset curing temperature of DGEBA was 55.8 °C. In addition, tensile strength and Izod impact strength of the vanillin-based epoxy system in the presence of inorganic accelerators increased in comparison to the DGEBA system. Moreover, in order to study the effect of inorganic accelerators on the toughness of the synthesized vanillin-based epoxy resin, fracture surfaces from Izod impact strength tests were observed using scanning electron microscopy (SEM) which confirmed improving mechanical properties.

106 citations

Journal ArticleDOI
TL;DR: In this paper, Amino-functionalized nanoclay was used as a linkage between carbon fiber surface and epoxy matrix, which by a cation exchange process was grafted on the CF surface.

84 citations

Journal ArticleDOI
TL;DR: In this paper, multi-walled carbon nanotubes (MWCNTs) were incorporated to an epoxy matrix reinforced with ultra-high molecular weight polyethylene (UHMWPE) fiber.

76 citations


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Book ChapterDOI
22 Apr 2012
TL;DR: In this article, the electromagnetic spectrum in Figure 1 illustrates the many different types of electromagnetic radiation, including gamma rays (γ-rays), X-rays, ultraviolet (UV) radiation, visible light, infrared (IR), microwaves, and radio waves.
Abstract: Spectroscopy is the study of matter interacting with electromagnetic radiation (e.g., light). The electromagnetic spectrum in Figure 1 illustrates the many different types of electromagnetic radiation, including gamma rays (γ-rays), X-rays, ultraviolet (UV) radiation, visible light, infrared (IR) radiation, microwaves, and radio waves. The frequency (ν) and wavelength (λ) ranges associated with each form of radiant energy are also indicated in Figure 1.

849 citations

Journal ArticleDOI
TL;DR: In this paper, a comprehensive review on the design, performances, applications and challenges of polymeric polymeric nanocomposites is presented, focusing on the combination effect between nanomaterials with variable dimensions and scales, and conventional phosphorus-, nitrogen- and/or silicon-containing flame retardants.

342 citations

Journal ArticleDOI
TL;DR: In this article, an overview of the fabrication techniques for super-hydrophobic coating and self-cleaning (SC) applications in various fields is presented, along with the critical conclusions, forthcoming views, and obstacles on the field of the durability of SCT are discussed in the presented survey.

299 citations

Journal ArticleDOI
TL;DR: It is hoped this review will stimulate further advances in the sustainable production of value-added products from lignin to integrate this invaluable "bio-waste" into the chemical/materials supply chain.
Abstract: Despite the enormous research efforts in recent years regarding lignin depolymerisation and functionalisation, few commercial products are available. This review provides a summary and viewpoint of extensive research in the lignin-to-product valorisation chain, with an emphasis on downstream processing of lignin derived feedstock into end products. It starts with an introduction of available platform chemicals and polymeric derivatives generated from lignin via existing depolymerisation and functionalisation technologies. Following that, detailed analyses of various strategies for the downstream processing of lignin derived platform chemicals and materials into fuels, valued-added chemicals and functional polymers are provided. A concise techno-economic analysis of various downstream processes is conducted based on the market demand of the end product, economic potential and technological readiness, enabling the identification of processes that are potentially both economically competitive and commercially feasible, and shedding light on processes which deserve further technological development. We wish this review will stimulate further advances in the sustainable production of value-added products from lignin to integrate this invaluable “bio-waste” into the chemical/materials supply chain.

232 citations