Papers by Mabrouk Ouederni
Journal of Materials in Civil Engineering, Jun 1, 2022
Craniosynostosis represents a heterogeneous cluster of congenital disorders and manifests as prem... more Craniosynostosis represents a heterogeneous cluster of congenital disorders and manifests as premature ossification of one or more cranial sutures. Cranial sutures serve to enable calvarial growth and function as joints between skull bones. The mechanical properties of synostosed cranial sutures are of vital importance to their function and yet are poorly understood. The present study was designed to characterize the nanostructural and nanomechanical properties of synostosed postnatal sagittal and metopic sutures. Synostosed postnatal sagittal sutures (n 5 5) and metopic sutures (n 5 5) were obtained from craniosynostosis patients (aged 9.1 ± 2.8 months). The synostosed sutural samples were prepared for imaging and indentation on both the endocranial and ectocranial surfaces with the cantilever probe of an atomic force microscopy. Analysis of the nanotopographic images indicated robust variations in sutural surface characteristics with localized peaks and valleys. In 5 3 5 mm scan sizes, the surface roughness of the synostosed metopic suture was significantly greater (223.6 ± 93.3 nm) than the synostosed sagittal suture (142.9 ± 80.3 nm) (P , 0.01). The Young's modulus of the synostosed sagittal suture at 0.7 ± 0.2 MPa was significantly higher than the synostosed metopic suture at 0.5 ± 0.1 MPa (P , 0.01). These data suggest that various synostosed cranial sutures may have different structural and mechanical characteristics.
Express Polymer Letters, 2021
With the excessive use of polyolefins in commercial and industrial sectors, polyolefins, specific... more With the excessive use of polyolefins in commercial and industrial sectors, polyolefins, specifically polyethylenes (P.E.s), have received substantial attention and became a fundamental topic of research. Their demand has been reported to increase globally, and the current estimated production is well in excess of 100 million tons. Due to their unique and outstanding properties such as their toughness and flexibility, even at low temperatures, excellent chemical resistance, easy processability, no odor and toxicity, and their low cost, P.E.s have been widely used for numerous applications such as packaging, buildings, electrical fittings, and agricultural piping [1]. However, P.E.s like all organic materials suffer from poor weathering resistance under the influence of the different
International Journal of Polymer Science, 2016
The focus of this work is to develop the knowledge of prediction of the physical and chemical pro... more The focus of this work is to develop the knowledge of prediction of the physical and chemical properties of processed linear low density polyethylene (LLDPE)/graphene nanoplatelets composites. Composites made from LLDPE reinforced with 1, 2, 4, 6, 8, and 10 wt% grade C graphene nanoplatelets (C-GNP) were processed in a twin screw extruder with three different screw speeds and feeder speeds (50, 100, and 150 rpm). These applied conditions are used to optimize the following properties: thermal conductivity, crystallization temperature, degradation temperature, and tensile strength while prediction of these properties was done through artificial neural network (ANN). The three first properties increased with increase in both screw speed and C-GNP content. The tensile strength reached a maximum value at 4 wt% C-GNP and a speed of 150 rpm as this represented the optimum condition for the stress transfer through the amorphous chains of the matrix to the C-GNP. ANN can be confidently used ...
Ageing characteristics of polyethylene-modified asphalt binders blended with different compatibilisers
Road Materials and Pavement Design
An Adhesion Improvement of Low-Density Polyethylene to Aluminum through Modification with Functionalized Polymers
Polymers, Feb 11, 2023
Air-laid web with high modulus fibers
Journal of Environmental Management, 2015
The treatment of spent caustic produced from an ethylene plant was investigated. In the case of n... more The treatment of spent caustic produced from an ethylene plant was investigated. In the case of neutralization alone it was found that the maximum removal of sulfide was at pH values below 5.5. The higher percentage removal of sulfides (99% at pH ¼ 1.5) was accompanied with the highest COD removal (88%). For classical oxidation using H 2 O 2 the maximum COD removal percentage reached 89% at pH ¼ 2.5 and at a hydrogen peroxide concentration of 19 mM/L. For the advanced oxidation using Fenton's process it was found that the maximum COD removal of 96.5% was achieved at a hydrogen peroxide/ferrous sulfate ratio of (7:1).
Engineering Education in the Middle East and North Africa: An Industry Perspective
Advances in Engineering Education in the Middle East and North Africa, 2015
The Middle East and North Africa (MENA) region is poised to undergo tremendous industrial develop... more The Middle East and North Africa (MENA) region is poised to undergo tremendous industrial development on the way to diversify its economy and become less dependent on oil and gas revenues. Industrial development has always been linked to the ingenuity and innovation of engineering minds. In this chapter, we examine engineering education in the MENA region from the perspective of a large industrial organization that has been depending on engineers, training them and developing them for more than 30 years. The critical engineering skills required by industry are discussed and the role of engineering education in helping industry succeed is emphasized. Close collaboration between industry and engineering schools is very important in order to ensure that students are well prepared to join the workforce and contribute to solving industry’s and society’s problems. This collaboration should focus not only on technical abilities but also on developing soft skills. Critical thinking and problem solving stand out as leading skills that are highly required for engineering graduates to succeed in industry. These skills also need more attention from engineering programs in the region in order to prepare the professional engineers needed by industry. Other important aspects of engineering education in the region include the role of internships, research and innovation, and the critical importance of integrating safety into engineering education.
Novel Alternative to Free Oil Remediation and Recovery: Foamy Absorbents Designed from Low Molecular Paraffinic Waste
SSRN Electronic Journal
Effect of GNPs addition and Uniaxial/Biaxial drawing on PA6/GNPs and PP/GNPs composites
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...
LLDPE/Graphene Nano-composites: Synthesis and Characterization
Qatar Foundation Annual Research Conference Proceedings Volume 2016 Issue 1, 2016
The development of nano-composite materials is making a significant impact on modern technology d... more The development of nano-composite materials is making a significant impact on modern technology due to their wide range of applications and their superior properties1. Several methods have been proposed and developed to prepare polymer nano-composites. Graphene nano-composites, in particular, have attracted the interest of researchers because of their excellent properties, such as high electrical conductivity, high thermal stability and excellent mechanical strength 2–3. Graphene, a two-dimensional carbon atoms structure, exhibits exceptional properties4–5. Incorporating these nano-fillers with high performance polymers results in a unique combinations of properties. This paper reports on the synthesis and characterization of graphene and LLDPE (Linear Low Density Polyethylene)/graphene nano-composites with different weight ratios of graphene. Graphene was synthesized from graphene oxide, which was prepared by using modified hammers method. The obtained few layers of graphene were confirmed by different characterization methods such as FTIR, XRD, Raman spectroscopy and SEM. LLDPE/Graphene composites at different weight ratios of graphene, i.e. 1, 4, and 8 wt% were compounded in twin screw extruder. Extruded granules of LLDPE/Graphene materials were used in the preparation of nano-composites by compression molding. In this research, we used the LLDPE as the polymer matrix, because PE (polyethylene) is one of the most common plastic resins in the world and it is produced on a large scale in the State of Qatar by Qatar Petrochemical Company (QAPCO). LLDPE has grown most rapidly within the PE family due to its good balance of mechanical properties and process-ability compared to other types of PE. The effect of graphene ratio on the mechanical, thermal and electrical properties were investigated. LLDPE/Graphene composites with 4% graphene showed higher tensile strength and tensile modulus than the other graphene loading composites. Agglomeration was a problem in the composites with high wt% of the graphene which caused the reduction in tensile properties. Graphene marginally increased the melting temperature of the nano-composites whereas crystallization temperature, thermal stability and electrical conductivity were increased with increase of graphene loading. The results obtained showed that the graphene can increase the thermal stability of the polymer mixture. Increment of thermal stability is due to the high thermal stability of the graphene and the formation of phonon and charge carrier networks in the matrix. The electrical conductivity of LLDPE is 4.28 × 10− 11 and for nano composites is 9.2 × 10− 05. The high electrical conductivity of the graphene converts the LLDPE polymer insulator to an electrical conductor. Electrically conductive PE based composite materials can be used as electron magnetic-reflective materials, as well as in high voltage cables. The enhancement in mechanical, thermal and electrical properties of LLDPE/Graphene nano-composites achieved by melt mixing of graphene into the polymer can enable mass production of new and low cost novel materials with superior tensile strength, thermal stability and electrical conductivity. References 1. Gossard Didier, Karkri Mustapha, Mariam A. AlMaadeed, Igor Krupa A new experimental device and inverse method to characterize thermal properties of composite phase change materials. Compos. Struct. 2015,133(1), 1149–1159. 2. X. Huang, Z. Yin, S. Wu, X. Qi, Q. He, Q. Zhang, Q. Yan, F. Boey, H. Zhang. Graphene based materials: synthesis, characterization, properties and application. Smal. 2011, 18, 1876–1902. 3. J.R. Potts, D.R. Dreyer, C.W. Bielawski, R.S. Ruoff. Graphene based polymer nanocomposites. Polymer 2011, 52, 5–25. 4. T. Kulia, S. Bhadra, D. Yao, N.H. Kim, S. Bose, J.H. Lee. Recent advances in graphene based polymer composites. Prog. Polym. Sci. 2010, 35, 1350–1375. 5. Du J, Cheng HM. The Fabrication, Properties and Uses of Graphene/Polymer Composites. Macromolecular Chemistry and Physics 2012;213:1060–1077.
Surface and Coatings Technology, 2018
Polymers/metal laminates are often used to improve physical and mechanical properties, especially... more Polymers/metal laminates are often used to improve physical and mechanical properties, especially those required in building applications. A flat aluminum composite panel (ACP) consisted mainly of two thin metal sheets usually made of aluminum (Al) and a non-metal core, such as polyethylene (PE). The lack of adhesion associated with the low wettability of PE is a serious problem. An eco-friendly, dry, non-destructive corona treatment technique can be applied to solve this problem. In this work, the use of a corona treatment to enhance the adhesion properties of linear low-density polyethylene (LLDPE) was studied. The changes in surface and adhesion properties were thoroughly analyzed using various analytical techniques and methods to obtain the optimal parameters for corona discharge using contact angle measurements, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). AFM force adhesion measurements were used to analyze the effect of the corona treatment on the adhesion enhancement of LLDPE, and the peel tests confirmed a significant increase in peel resistance in the LLDPE/Al laminate. A synergy effect from using the corona treatment in combination with an ethylene acrylic acid dispersion primer was observed.
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...
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...
Positive influence of expanded graphite on the physical behavior of phase change materials based on linear low-density polyethylene and paraffin wax
Thermochimica Acta, 2015
ABSTRACT The preparation of Phase Change Materials (PCM) with improved thermal conductivity, base... more ABSTRACT The preparation of Phase Change Materials (PCM) with improved thermal conductivity, based on linear low-density polyethylene (LLDPE), paraffin wax with a melting point of approximately 42C and expanded graphite as well as the investigation of their physical behavior is reported in this paper. The absorption of heat energy is realized by phase transitions in the wax structure, i.e., solid–solid transitions between different crystalline structures of wax and, primarily, by a solid–liquid transition. An estimate of the total heat energy that can be reversibly absorbed or released by the designed materials was determined using Differential Scanning Calorimetry (DSC). The improvement in the thermal conductivity of the polymeric materials was obtained by incorporating expanded graphite into the blends. Expanded graphite has a reinforcing effect on the PCM, resulting in an increase in the toughness (Young's modulus) Significant amounts of wax are leached from the samples, and a higher wax content also results in more wax leakage. Graphite significantly reduces the wax loss from the samples.
Mechanical, morphological and thermal properties of chitosan filled polypropylene composites: The effect of binary modifying agents
Composites Part A: Applied Science and Manufacturing, 2013
ABSTRACT This work investigates the effects of the binary modifying agents–organosolv lignin and ... more ABSTRACT This work investigates the effects of the binary modifying agents–organosolv lignin and acrylic acid, on the mechanical and thermal properties of chitosan-filled polypropylene (PP) composites. We analyse the mechanical and the thermal properties of the composites by means of ASTM D 638-91, ASTM D 256, thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). Tensile strength of the composites decreases upon the addition of chitosan, but Young’s modulus improves. Impact strength is found to increase with the maximum value at 30 php. The chemical modifications do not alter the stress–strain character or the thermal degradation mechanism of the composites considerably; however the results of this study show that the treated composites are found to have better mechanical and thermal properties than untreated composites. Furthermore, the obtained results are comparable to results from previous work. This outcome implies that organosolv lignin could be a potential reagent to partially replace its synthetic counterpart.
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...
Polymers in textiles
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.
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Papers by Mabrouk Ouederni