Papers by Mabrouk Ouederni
Road Materials and Pavement Design
Polymers, Feb 11, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Frontiers in Materials, 2021
In this work, polypropylene (PP) nanocomposites containing different weight concentration of grap... more In this work, polypropylene (PP) nanocomposites containing different weight concentration of graphene nanoplatelets (GNP) were prepared by melt-mixing using an industrial-scale, co-rotating, intermeshing, twin-screw extruder. The materials were then compression moulded into sheets, and biaxially stretched at different stretching ratios (SRs) below the PP melting temperature. The effects of GNP content and biaxial stretching on the bulk properties of unfilled PP and PP/GNP nanocomposites have been investigated in details. Results show that the addition of GNP (>5wt%) can lead to electrically conductive composites due to the formation of percolation network. The GNP have led to increased polymer crystallinity and enhanced materials stiffness and strength. Biaxial stretching process further enhances the materials mechanical properties but has slightly decreased the composites electrical conductivity. The PP/GNP nanocomposites were also processed into 3D demonstrator parts using vacu...
In this paper, the processing and characterization of Polyamide 6 (PA6) nanocomposites containing... more In this paper, the processing and characterization of Polyamide 6 (PA6) nanocomposites containing graphite nanoplatelets (GNPs) is reported. PA6 nanocomposites were prepared by melt-mixing using an industrial, co-rotating, intermeshing, twin-screw extruder. A bespoke screw configuration was used that was designed in-house to enhance nanoparticle dispersion into a polymer matrix. The effects of nanofiller content and uniaxial stretching on the bulk properties of the PA6/GNPs nanocomposites were investigated. The crystalline structures of PA6/GNPs nanocomposites are related to thermal treatment, stress history and the presence of moisture and nanofillers. DSC, Raman and XRD studies show an increase in crystallinity with increasing GNPs content as a result of the heterophase nucleation effect. The effect of uniaxial stretching on PA6 nanocomposites was investigated by drawing specimens heated at temperatures below the melting temperature. DSC and Raman studies of the drawn samples show...
Linear low-density polyethylene is a commonly utilized polymer in the industry because of its uni... more Linear low-density polyethylene is a commonly utilized polymer in the industry because of its unique structure and excellent overall performance. It is produced by polymerizing ethylene with a slight amount of an α-olefin. LLDPE, however, is not photodegradation resistant, and its relatively low mechanical properties and thermal stability can sometimes limit its application in industry. The development of particulate reinforced polymer composites is currently viewed as one of the highly promising methodologies in the area of next-generation engineering products [1–3]. Polymer composites are an essential category of polymers that has broad applications in a number of various industrial areas and therefore have been comprehensively researched in the last few decades [4–7]. Inorganic fillers are believed to be extremely critical both technologically and economically, including carbon black, which is very valuable in the thermoplastic industry [8]. Further, the development of electrical...
Building Resilience at Universities: Role of Innovation and Entrepreneurship, 2021
The low-density polyethylene/aluminum (LDPE/Al) joint in Tetra Pak food container provides stabil... more The low-density polyethylene/aluminum (LDPE/Al) joint in Tetra Pak food container provides stability and strength to food packaging, ensures protection against outside moisture, and maintains the nutritional values and flavors of food without the need for additives in the food products. However, it was found that the adhesion strength of LDPE with Al is weak or almost non-existent, due to the non-polar hydrophobic LDPE surface. Therefore, it was necessary to apply surface treatment to LDPE. Plasma-assisted grafting of the LDPE surface with different molecular weight compounds of polyethylene glycol (PEG) was used to improve LDPE/Al adhesion. It was found that this surface modification contributed to significantly improve the wettability of the LDPE surface, as was confirmed by contact angle measurements. The chemical composition changes after plasma treatment and modification process was observed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (...
Advanced Manufacturing: Polymer & Composites Science, 2016
The influence of two types of graphene nanoplatelets (GNPs) on the physicomechanical properties o... more The influence of two types of graphene nanoplatelets (GNPs) on the physicomechanical properties of linear low-density polyethylene (LLDPE) was investigated. The addition of these two types of GNPs-designated as grades C and M-enhanced the thermal conductivity of the LLDPE, with a more pronounced improvement resulting from the M-GNPs compared to C-GNPs. Improvement in electrical conductivity and decomposition temperature was also noticed with the addition of GNPs. In contrast to the thermal conductivity, C-GNPs resulted in greater improvements in the electrical conductivity and thermal decomposition temperature. These differences can be attributed to differences in the surface area and dispersion of the two types of GNPs.
Journal of the Mechanical Behavior of Biomedical Materials, 2017
This contribution is focused on the Mullins effect in polyethylene. An ultra-low-density polyethy... more This contribution is focused on the Mullins effect in polyethylene. An ultra-low-density polyethylene with 0.15 crystal content, a low-density polyethylene with 0.3 crystal content and a high-density polyethylene with 0.72 crystal content are subjected to cyclic stretching over a large strain range. Experimental observations are first reported to examine how the crystal content influences the Mullins effect in polyethylene. It is found that the cyclic stretching is characterized by a stress-softening, a hysteresis and a residual strain, whose amounts depends on the crystal content and the applied strain. A unified viscohyperelastic-viscoelastic-viscoplastic constitutive model is proposed to capture the polyethylene response over a large strain range and its crystal-dependency. The macro-scale polyethylene response is decomposed into two physically distinct sources, a viscoelastic-viscoplastic intermolecular part and a viscohyperelastic network part. The local inelastic deformations of the rubbery amorphous and crystalline phases are considered by means of a micromechanical treatment using the volume fraction concept. Experimentally-based material kinetics are designed by considering the Mullins effect crystaldependency and are introduced into the constitutive equations to capture the experimental 2 observations. It is shown that the model is able to accurately reproduce the Mullins effect in polyethylene over a large strain range. The inherent deformation mechanisms are finally presented guided by the proposed constitutive model.
RSC Advances, 2015
The incorporation of graphene nanoplatelets into nylon (PA6)viamelt processing on an industrial s... more The incorporation of graphene nanoplatelets into nylon (PA6)viamelt processing on an industrial scale significantly increases the crystallinity, stiffness, and electrical conductivity of the resulting composites.
Polymer Science and Innovative Applications, 2020
Abstract The ability to shape polymeric materials into fibers has revolutionized the textile indu... more Abstract The ability to shape polymeric materials into fibers has revolutionized the textile industry. Synthetic fibers not only offered a solution to some of the shortcomings of natural fibers, but also made it possible to design textile fabrics for use in new, and high performance, applications. This chapter deals with the use of manmade polymeric fibers in the textile industry. The manufacturing of synthetic fibers as well as their characterization techniques are described. This chapter also discusses the most popular polymeric fibers on the market and describes in detail their unique properties and most common applications. Special emphasis is put on the use of polymers in technical textiles with the aim of relating the highly demanding performance of technical textiles to the unique properties of the base polymer.
Polymers, 2021
Foamed phase-change materials (FPCMs) were prepared using recycled linear low-density polyethylen... more Foamed phase-change materials (FPCMs) were prepared using recycled linear low-density polyethylene (LLDPE) blended with 30 wt.% of paraffin wax (PW) and foamed by 1,1′-azobiscarbamide. The protection of pores’ collapse during foaming process was insured through chemical cross-linking by organic peroxide prior foaming. This work represents one of very few attempts for a preparation of polymeric phase change foams without a use of micro-encapsulated phase change component leading to the enhancement of the real PCM component (PW) within a final product. The porous structure of fabricated foams was analyzed using micro-computed tomography, and direct observation, and reconstruction of the internal structure was investigated. The porosity of FPCMs was about 85–87 vol.% and resulting thermal conductivity 0.054–0.086 W/m·K. Differential Scanning Calorimetry was used to determine the specific enthalpies of melting (22.4–25.1 J/g) what is the latent heat of materials utilized during a heat a...
Vacuum, 2016
Composites of Linear Low Density Polyethylene (LLDPE) and Graphene Nanoplatelets (GNPs) were proc... more Composites of Linear Low Density Polyethylene (LLDPE) and Graphene Nanoplatelets (GNPs) were processed using a twin screw extruder under different extrusion conditions. The effects of screw speed, feeder speed and GNP content on the electrical, thermal and mechanical properties of composites were investigated. The inclusion of GNPs in the matrix improved the thermal stability and conductivity by 2.7% and 43%, respectively. The electrical conductivity improved from 10-11 to 10-5 S/m at 150 rpm due to the high thermal stability of the GNPs and the formation of phonon and charge carrier networks in the polymer matrix. Higher extruder speeds result in a better distribution of the GNPs in the matrix and a significant increase in thermal stability and thermal conductivity. However, this effect is not significant for the electrical conductivity and tensile strength. The addition of GNPs increased the viscosity of the polymer, which will lead to higher processing power requirements. Increasing the extruder speed led to a reduction in viscosity, which is due to thermal degradation and/or chain scission. Thus, while high speeds result in better dispersions, the speed needs to be optimized to prevent detrimental impacts on the properties.
Materials and Structures
In recent years, the use of polyethylene (PE) for asphalt modification has been gaining increased... more In recent years, the use of polyethylene (PE) for asphalt modification has been gaining increased attention due to the environmental sustainability and cost-saving benefits. To optimize the performance of the PE-asphalt blends, it is necessary to understand the polymer-binder interactions and their impact on the properties of the modified asphalt binder. In this study, low-density polyethylene (LDPE) with low and high melt flow index (MFI), i.e., LDPE4 and LDPE70, were blended with Pen 60-70 asphalt binder in dosages ranging from 1 to 5 wt.%. PE Wax was also added to the binder or the PE-binder blend to enhance dispersion. The dispersion of PE in the binder and the phase stability of the modified binder were investigated by optical microscope. The equivalent diameter of PE domains increased with time and the polymer dosage level. The addition of PE wax improved the polymer dispersity in the LDPE4 blends. The polymer dispersity in LDPE70 blends was good without adding PE Wax, attribu...
Materials
This paper addresses the preparation and characterization of efficient adsorbents for tertiary tr... more This paper addresses the preparation and characterization of efficient adsorbents for tertiary treatment (oil content below 100 ppm) of oil/water emulsions. Powdered low-density polyethylene (LDPE) was modified by radio-frequency plasma discharge and then used as a medium for the treatment of emulsified diesel oil/water mixtures in the concentration range from 75 ppm to 200 ppm. Plasma treatment significantly increased the wettability of the LDPE powder, which resulted in enhanced sorption capability of the oil component from emulsions in comparison to untreated powder. Emulsions formed from distilled water and commercial diesel oil (DO) with concentrations below 200 ppm were used as a model of oily polluted water. The emulsions were prepared using ultrasonication without surfactant. The droplet size was directly proportional to sonication time and ranged from 135 nm to 185 nm. A sonication time of 20 min was found to be sufficient to prepare stable emulsions with an average droplet...
Qatar Foundation Annual Research Conference Proceedings Volume 2014 Issue 1
Qatar Foundation Annual Research Conference Proceedings Volume 2016 Issue 1
Qatar Foundation Annual Research Conference Proceedings Volume 2016 Issue 1
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Papers by Mabrouk Ouederni