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Dive into the research topics where Mehdi Ghaffari is active.

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Featured researches published by Mehdi Ghaffari.


RSC Advances | 2017

Biowaste chicken eggshell powder as a potential cure modifier for epoxy/anhydride systems: competitiveness with terpolymer-modified calcium carbonate at low loading levels

Mohammad Reza Saeb; Mehdi Ghaffari; Hadi Rastin; Hossein Ali Khonakdar; Frank Simon; Farhood Najafi; Vahabodin Goodarzi; P Poornima Vijayan; Debora Puglia; Farzaneh Hassanpour Asl; Krzysztof Formela

Biowaste chicken eggshell (ES) powder was applied as a potential cure modifier in epoxy/anhydride systems. Cure behaviour and kinetics of composites filled with very low content (0.1 wt% based on epoxy resin) of ES, calcium carbonate (CaCO3), and terpolymer-modified fillers, mES and mCaCO3, were discussed comparatively. Surface analysis was performed by X-ray photoelectron spectroscopy. Cure kinetics was investigated by differential (Friedman) and integral (Ozawa and Kissinger–Akahira–Sunose) isoconversional methods using dynamic differential scanning calorimetry (DSC) data. Overall, protein precursors naturally existing in the structure of pristine ES facilitated crosslinking of epoxy and hardener of anhydride with functional groups resulting from terpolymer attachment to CaCO3 particles. Accelerated/hindered cure was observed depending on the filler type and surface characteristics, as investigated via the autocatalytic/non-catalytic nature of reactions and comparison of activation energy values of four types of composites. An enhanced cure was identified for composites containing untreated ES, which could be inferred on account of the lower competitive cure of carboxyl groups in the terpolymer backbone with epoxy compared to peptide groups existing in microporous pristine ES. On the other hand, mCaCO3 revealed low values of activation energy compared to pristine CaCO3, but still of the same order as ground biowaste ES.


Materials Science and Engineering: C | 2017

Effect of high energy electron beam (10 MeV) on specific heat capacity of low-density polyethylene/hydroxyapatite nano-composite

Zahra Soltani; F. Ziaie; Mehdi Ghaffari; A.M. Beigzadeh

In the present work, thermal properties of low density polyethylene (LDPE) and its nano composites are investigated. For this purpose LDPE reinforced with different weight percents of hydroxyapatite (HAP) powder which was synthesized via hydrolysis method are produced. The samples were irradiated with 10MeV electron beam at doses of 75 to 250kGy. Specific heat capacity measurement have been carried out at different temperatures, i.e. 25, 50, 75 and 100°C using modulated temperature differential scanning calorimetry (MTDSC) apparatus and the effect of three parameters include of temperature, irradiation dose and the amount of HAP nano particles as additives on the specific heat capacity of PE/HAP have been investigated precisely. The MTDSC results indicate that the specific heat capacity have decreased by addition of nano sized HAP as reinforcement for LDPE. On the other hand, the effect of radiation dose is reduction in the specific heat capacity in all materials including LDPE and its nano composites. The HAP nano particles along with cross-link junctions due to radiation restrain the movement of the polymer chains in the vicinity of each particle and improve the immobility of polymer chains and consequently lead to reduction in specific heat capacity. Also, the obtained results confirm that the radiation effect on the specific heat capacity is more efficient than the reinforcing effect of nano-sized hydroxyapatite.


Journal of Polymer Engineering | 2016

Weldability of pipe grade polyethylenes as realized from thermal and mechanical properties assessments

Vahabodin Goodarzi; Zahed Ahmadi; Mohammad Reza Saeb; Farkhondeh Hemmati; Mehdi Ghaffari; Krzysztof Formela

Abstract Since polyethylene (PE) has been widely accepted for the production of high-pressure fluid conveying pipelines, studies devoted to weldability of PE connections were always of major importance. In this study, two industrial PE grades designed for pipe production, namely PE80 and PE100, were injection molded, cut, and then welded as PE100-PE100, PE100-PE80, and PE80-PE80. The heat-welded joints were assessed by differential scanning calorimetry and tensile measurements. The results obtained from thermal and mechanical analyses were compared with equivalents for aged samples. Thermal analysis revealed that the melting point of the PE100-PE100 sample is obviously larger than the one for the PE80-PE80 joint, for the PE80 chains deteriorate the crystallization of PE100. Further, the PE80-PE80 sample showed the lowest lamellar thickness and crystalline molecular weight among the studied joints. The aging process was found to increase lamellar thickness and molecular weight, though in the PE100-PE100 sample such quantities very limitedly increased. The yield stress of aged joints was higher than that for just-prepared samples, while an inverse trend was seen for strain at break. From a practical viewpoint, the PE100-PE100 welds offer better properties.


European Polymer Journal | 2008

Rheology, morphology and mechanical properties of polyethylene/ethylene vinyl acetate copolymer (PE/EVA) blends

M. Faker; M. K. Razavi Aghjeh; Mehdi Ghaffari; S.A. Seyyedi


Thermochimica Acta | 2012

The kinetic analysis of isothermal curing reaction of an epoxy resin-glassflake nanocomposite

Mehdi Ghaffari; Morteza Ehsani; Hossein Ali Khonakdar; Guy Van Assche; H. Terryn


Thermochimica Acta | 2012

Evaluation of curing kinetic parameters of an epoxy/polyaminoamide/nano-glassflake system by non-isothermal differential scanning calorimetry

Mehdi Ghaffari; Morteza Ehsani; Hossein Ali Khonakdar; Guy Van Assche; H. Terryn


Journal of Physical Chemistry C | 2016

A Close-up of the Effect of Iron Oxide Type on the Interfacial Interaction between Epoxy and Carbon Steel: Combined Molecular Dynamics Simulations and Quantum Mechanics

Ghasem Bahlakeh; Mehdi Ghaffari; Mohammad Reza Saeb; Bahram Ramezanzadeh; Frank De Proft; H. Terryn


Progress in Organic Coatings | 2017

Cure kinetics of epoxy/β-cyclodextrin-functionalized Fe3O4 nanocomposites: Experimental analysis, mathematical modeling, and molecular dynamics simulation

Mohammad Reza Saeb; Hadi Rastin; Meisam Shabanian; Mehdi Ghaffari; Ghasem Bahlakeh


Corrosion Science | 2016

Demonstration of epoxy/carbon steel interfacial delamination behavior: Electrochemical impedance and X-ray spectroscopic analyses

Mehdi Ghaffari; Mohammad Reza Saeb; B. Ramezanzadeh; Peyman Taheri


Journal of Applied Polymer Science | 2017

Cure kinetics of epoxy/MWCNTs nanocomposites: Nonisothermal calorimetric and rheokinetic techniques

Mohammad Reza Saeb; Hadi Rastin; Milad Nonahal; Mehdi Ghaffari; Ali Jannesari; Krzysztof Formela

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H. Terryn

Vrije Universiteit Brussel

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Krzysztof Formela

Gdańsk University of Technology

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Guy Van Assche

Vrije Universiteit Brussel

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Peyman Taheri

University of California

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Frank De Proft

Vrije Universiteit Brussel

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