Said Lotfi Hafsaoui - Academia.edu (original) (raw)

Uploads

Papers by Said Lotfi Hafsaoui

Research paper thumbnail of Erratum to: Measurement and prediction of solid–liquid phase equilibria for systems containing biphenyl in binary solution with long chain n-alkanes

Journal of Thermal Analysis and Calorimetry, 2016

Research paper thumbnail of Preparation and characterization of hybrid fibers based on graphene oxide-wood flour for advanced applications

Materials Today: Proceedings, 2021

Research paper thumbnail of Etude et modélisation de la stabilité thermique et des propriétés des polyamides au cours du rotomoulage

Le moulage par rotation est une technique de mise en oeuvre des polymeres thermoplastiques. Ce pr... more Le moulage par rotation est une technique de mise en oeuvre des polymeres thermoplastiques. Ce procede fait l'objet de plusieurs etudes durant cesdernieres annees. La finalite de notre travail est la modelisation thermique et chimique de ce procede, tenant compte de la nature des polyamides, du changement de phases et en particulier la cristallisation et la fusion. Ces changements de phases ont ete traites numeriquement pour chaque couche de polymere, a l'aide d'une methode dite enthalpique puis par une autre methode derivee de la cinetique de cristallisation. Cette derniere a ete modifiee et adaptee a notre travail en procedant a un couplage de deux concepts ; le premier traduit le degagement de la chaleur lors de la transformation dela cristallinite, le deuxieme concept est la modelisation chimique de lathermodegradation des polyamides.

Research paper thumbnail of Solid-liquid equilibria of binary systems containing n-tetracosane with naphthalene or dibenzofuran

Research paper thumbnail of Study of polyamide 12 crystallization behavior within rotational molding process

Iranian Polymer Journal, 2013

Our study is focused on the investigation of polyamide 12 (PA 12) grade behavior in rotational mo... more Our study is focused on the investigation of polyamide 12 (PA 12) grade behavior in rotational molding process. Hence, some rotational molding tests of polyamide 12 were conducted on a STP LAB 40 machine. To simulate the cooling stage within the rotational molding, the crystallization behavior of polyamide 12 was studied using differential scanning calorimetry technique and the obtained results for non-isothermal crystallization were fitted with Ozawa model. Furthermore, morphology survey has been carried out by a hot stage method using a microscope to investigate the spherulites evolution which depends on the temperature. The micro-tensile properties have been studied using micro-tensile bench (MVTV2) to explain the mechanical behavior of polyamide 12 during crystallization. As a result, the rotational molding of PA 12 was successfully carried out. The simulation of the melting and crystallization stages, by application of Ozawa model coupled with enthalpy method gave a good representation of experimental data on one hand. On the other hand, all characterization revealed useful information to understand the different phenomena that govern the rotational molding process.

Research paper thumbnail of Preparation and characterization of hybrid fibers based on graphene oxide-wood flour for advanced applications

Materials Today: Proceedings

Research paper thumbnail of Study and modeling of high-density polyethylene coalescence under the extrussion conditions

International Journal of Material Forming

Research paper thumbnail of Stimulation and reinforcement of shape-memory polymers and their composites: A review

Journal of Thermoplastic Composite Materials

Shape-memory polymers (SMPs) and their composites (SMPCs), as a kind of smart materials, can resp... more Shape-memory polymers (SMPs) and their composites (SMPCs), as a kind of smart materials, can respond to particular external stimulus and recover the original shape. They present outstanding features encompassing shape-memory effect, deformability, biocompatibility, variable stiffness, lightweight, and so on. They have attracted considerable research interest in recent years. Several stimulation methods to actuate the deformation of SMPs and SMPCs, of which the thermal stimulation is the common one, and many types of reinforcements have been developed over the past few years. It is revealed that the SMPC thermal and mechanical properties can be improved by introducing a number of reinforcements. Therefore, to well investigate the SMPC characteristics upon exposure to a specific external stimulus, a deep knowledge and understanding of the potential reinforcements as well as the available stimulation methods are crucial. In this review, reinforcements such as fibers, ceramics, and nano...

Research paper thumbnail of Correction to: study and modeling of high-density polyethylene coalescence under the extrusion conditions

International Journal of Material Forming

The original publication of this article unfortunately contains error. The word "extrusion" was s... more The original publication of this article unfortunately contains error. The word "extrusion" was spelled incorrectly as "extrussion" in the article title. Publisher's note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Research paper thumbnail of Preparation and characterization of graphene/CdS nanocomposites

Applied Surface Science, 2010

Research paper thumbnail of Etude et modélisation de la stabilité thermique et des propriétés des polyamides au cours du rotomoulage

Http Www Theses Fr, Sep 9, 2013

Ce présent travail rentre dans le cadre d'une thèse de doctorat en co-tutelle entre l'Ecole Milit... more Ce présent travail rentre dans le cadre d'une thèse de doctorat en co-tutelle entre l'Ecole Militaire Polytechnique et Arts et Métiers Paritech, sous la direction du professeur Abbas TCHARKHTCHI et du professeur Saad LAMOURI, à qui je voudrais bien exprimer tous mes remerciements pour leur confiance. Ils m'ont laissé une liberté dans l'organisation de mon travail tout en veillant à maintenir le cap et sans qu'ils s'en désintéressent un seul instant. Je ne saurai les remercier assez pour leur rigueur scientifique et pour avoir su trouver le temps nécessaire pour contribuer à compléter ce travail. Je me faillirai à la tradition si je n'exprime ici mon gratitude envers l'Ecole à travers son Commandement. Ma reconnaissance va tout naturellement à M. Ahmed BENABOURA, Professeur à l'USTHB, pour avoir accepté de participer à ce Jury et d'en être le président. Il en est de même pour M. Farid BAKIR, Professeur à l'ENSAM de Paris, M. Xavier COLIN, Professeur à l'ENSAM de Paris, M. Mustapha KACI, Professeur à l'universié de Béjaia, M. Reda CHERIF, Maître de Conférences A à l'EMP, pour le temps qu'ils ont accordé à l'examen de ce travail, malgré un emploi du temps surchargé. Je leur exprime tous ma gratitude. Mes vifs remerciements vont aux Professeurs, Maitres de conférence, Docteurs (ou futurs), Ingénieurs et Techniciens pour ces cinq ans en votre compagnie

Research paper thumbnail of Thermal transfer simulation regarding the rotational moulding of polyamide 11

Journal of Thermal Analysis and Calorimetry, 2013

ABSTRACT Simulation of thermal phenomena in rotational moulding is very important to follow the e... more ABSTRACT Simulation of thermal phenomena in rotational moulding is very important to follow the evolution of the temperature in various zones of this process. It was a question of modelling heat gradients developing in rotational moulding part. Thermal model tested take into account the temperature change (thermal transfer mechanism) of melting and crystallization pseudo-stages (enthalpy method). Series of tests in polyamide 11 (PA11) were carried out by means of rotational moulding STP LAB, and non-isothermal crystallization kinetics of rotational moulding PA11 grade are measured and analysed by DSC technique type TAQ20. A result of non-isothermal crystallization of the studied polyamide was confronted with Ozawa model. In order to test the validity degree of enthalpy method (layer to layer), another approach based on Ozawa model has also been used in the case of cooling pseudo-stage. As results, the rotational moulding of PA11 was successfully carried out. The simulation of the fusion and crystallization stages, by application of Ozawa model coupled with enthalpy method gave a good representation of experimental data.

Research paper thumbnail of Measurement and prediction of solid–liquid phase equilibria for systems containing biphenyl in binary solution with long-chain n-alkanes

Solid–liquid equilibria of the n-alkanes (n-oc-tadecane, n-eicosane, n-tetracosane, n-pentacosane... more Solid–liquid equilibria of the n-alkanes (n-oc-tadecane, n-eicosane, n-tetracosane, n-pentacosane, n-triacon-tane) in biphenyl were measured by DSC 7 (Perkin-Elmer). It was found that all systems are simple eutectic. The solubility of the biphenyl in n-alkanes was studied in the temperature range 301–370 K. The experimental results were correlated using modified UNIFAC (Larsen and Gmehling versions) and ideal models. Good representation of solubility diagrams was obtained using partly readjusted UNIFAC parameters of Larsen version. Taking into account the large range of applicability of UNIFAC and the predictions of the activity coefficients for many other components in different classes of mixtures, we can conclude that the new experimental data for the systems mentioned in this work should be included in the database used by UNIFAC in order to evaluate better interaction parameters and to improve predictions.

Research paper thumbnail of Erratum to: Measurement and prediction of solid–liquid phase equilibria for systems containing biphenyl in binary solution with long chain n-alkanes

Journal of Thermal Analysis and Calorimetry, 2016

Research paper thumbnail of Preparation and characterization of hybrid fibers based on graphene oxide-wood flour for advanced applications

Materials Today: Proceedings, 2021

Research paper thumbnail of Etude et modélisation de la stabilité thermique et des propriétés des polyamides au cours du rotomoulage

Le moulage par rotation est une technique de mise en oeuvre des polymeres thermoplastiques. Ce pr... more Le moulage par rotation est une technique de mise en oeuvre des polymeres thermoplastiques. Ce procede fait l'objet de plusieurs etudes durant cesdernieres annees. La finalite de notre travail est la modelisation thermique et chimique de ce procede, tenant compte de la nature des polyamides, du changement de phases et en particulier la cristallisation et la fusion. Ces changements de phases ont ete traites numeriquement pour chaque couche de polymere, a l'aide d'une methode dite enthalpique puis par une autre methode derivee de la cinetique de cristallisation. Cette derniere a ete modifiee et adaptee a notre travail en procedant a un couplage de deux concepts ; le premier traduit le degagement de la chaleur lors de la transformation dela cristallinite, le deuxieme concept est la modelisation chimique de lathermodegradation des polyamides.

Research paper thumbnail of Solid-liquid equilibria of binary systems containing n-tetracosane with naphthalene or dibenzofuran

Research paper thumbnail of Study of polyamide 12 crystallization behavior within rotational molding process

Iranian Polymer Journal, 2013

Our study is focused on the investigation of polyamide 12 (PA 12) grade behavior in rotational mo... more Our study is focused on the investigation of polyamide 12 (PA 12) grade behavior in rotational molding process. Hence, some rotational molding tests of polyamide 12 were conducted on a STP LAB 40 machine. To simulate the cooling stage within the rotational molding, the crystallization behavior of polyamide 12 was studied using differential scanning calorimetry technique and the obtained results for non-isothermal crystallization were fitted with Ozawa model. Furthermore, morphology survey has been carried out by a hot stage method using a microscope to investigate the spherulites evolution which depends on the temperature. The micro-tensile properties have been studied using micro-tensile bench (MVTV2) to explain the mechanical behavior of polyamide 12 during crystallization. As a result, the rotational molding of PA 12 was successfully carried out. The simulation of the melting and crystallization stages, by application of Ozawa model coupled with enthalpy method gave a good representation of experimental data on one hand. On the other hand, all characterization revealed useful information to understand the different phenomena that govern the rotational molding process.

Research paper thumbnail of Preparation and characterization of hybrid fibers based on graphene oxide-wood flour for advanced applications

Materials Today: Proceedings

Research paper thumbnail of Study and modeling of high-density polyethylene coalescence under the extrussion conditions

International Journal of Material Forming

Research paper thumbnail of Stimulation and reinforcement of shape-memory polymers and their composites: A review

Journal of Thermoplastic Composite Materials

Shape-memory polymers (SMPs) and their composites (SMPCs), as a kind of smart materials, can resp... more Shape-memory polymers (SMPs) and their composites (SMPCs), as a kind of smart materials, can respond to particular external stimulus and recover the original shape. They present outstanding features encompassing shape-memory effect, deformability, biocompatibility, variable stiffness, lightweight, and so on. They have attracted considerable research interest in recent years. Several stimulation methods to actuate the deformation of SMPs and SMPCs, of which the thermal stimulation is the common one, and many types of reinforcements have been developed over the past few years. It is revealed that the SMPC thermal and mechanical properties can be improved by introducing a number of reinforcements. Therefore, to well investigate the SMPC characteristics upon exposure to a specific external stimulus, a deep knowledge and understanding of the potential reinforcements as well as the available stimulation methods are crucial. In this review, reinforcements such as fibers, ceramics, and nano...

Research paper thumbnail of Correction to: study and modeling of high-density polyethylene coalescence under the extrusion conditions

International Journal of Material Forming

The original publication of this article unfortunately contains error. The word "extrusion" was s... more The original publication of this article unfortunately contains error. The word "extrusion" was spelled incorrectly as "extrussion" in the article title. Publisher's note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Research paper thumbnail of Preparation and characterization of graphene/CdS nanocomposites

Applied Surface Science, 2010

Research paper thumbnail of Etude et modélisation de la stabilité thermique et des propriétés des polyamides au cours du rotomoulage

Http Www Theses Fr, Sep 9, 2013

Ce présent travail rentre dans le cadre d'une thèse de doctorat en co-tutelle entre l'Ecole Milit... more Ce présent travail rentre dans le cadre d'une thèse de doctorat en co-tutelle entre l'Ecole Militaire Polytechnique et Arts et Métiers Paritech, sous la direction du professeur Abbas TCHARKHTCHI et du professeur Saad LAMOURI, à qui je voudrais bien exprimer tous mes remerciements pour leur confiance. Ils m'ont laissé une liberté dans l'organisation de mon travail tout en veillant à maintenir le cap et sans qu'ils s'en désintéressent un seul instant. Je ne saurai les remercier assez pour leur rigueur scientifique et pour avoir su trouver le temps nécessaire pour contribuer à compléter ce travail. Je me faillirai à la tradition si je n'exprime ici mon gratitude envers l'Ecole à travers son Commandement. Ma reconnaissance va tout naturellement à M. Ahmed BENABOURA, Professeur à l'USTHB, pour avoir accepté de participer à ce Jury et d'en être le président. Il en est de même pour M. Farid BAKIR, Professeur à l'ENSAM de Paris, M. Xavier COLIN, Professeur à l'ENSAM de Paris, M. Mustapha KACI, Professeur à l'universié de Béjaia, M. Reda CHERIF, Maître de Conférences A à l'EMP, pour le temps qu'ils ont accordé à l'examen de ce travail, malgré un emploi du temps surchargé. Je leur exprime tous ma gratitude. Mes vifs remerciements vont aux Professeurs, Maitres de conférence, Docteurs (ou futurs), Ingénieurs et Techniciens pour ces cinq ans en votre compagnie

Research paper thumbnail of Thermal transfer simulation regarding the rotational moulding of polyamide 11

Journal of Thermal Analysis and Calorimetry, 2013

ABSTRACT Simulation of thermal phenomena in rotational moulding is very important to follow the e... more ABSTRACT Simulation of thermal phenomena in rotational moulding is very important to follow the evolution of the temperature in various zones of this process. It was a question of modelling heat gradients developing in rotational moulding part. Thermal model tested take into account the temperature change (thermal transfer mechanism) of melting and crystallization pseudo-stages (enthalpy method). Series of tests in polyamide 11 (PA11) were carried out by means of rotational moulding STP LAB, and non-isothermal crystallization kinetics of rotational moulding PA11 grade are measured and analysed by DSC technique type TAQ20. A result of non-isothermal crystallization of the studied polyamide was confronted with Ozawa model. In order to test the validity degree of enthalpy method (layer to layer), another approach based on Ozawa model has also been used in the case of cooling pseudo-stage. As results, the rotational moulding of PA11 was successfully carried out. The simulation of the fusion and crystallization stages, by application of Ozawa model coupled with enthalpy method gave a good representation of experimental data.

Research paper thumbnail of Measurement and prediction of solid–liquid phase equilibria for systems containing biphenyl in binary solution with long-chain n-alkanes

Solid–liquid equilibria of the n-alkanes (n-oc-tadecane, n-eicosane, n-tetracosane, n-pentacosane... more Solid–liquid equilibria of the n-alkanes (n-oc-tadecane, n-eicosane, n-tetracosane, n-pentacosane, n-triacon-tane) in biphenyl were measured by DSC 7 (Perkin-Elmer). It was found that all systems are simple eutectic. The solubility of the biphenyl in n-alkanes was studied in the temperature range 301–370 K. The experimental results were correlated using modified UNIFAC (Larsen and Gmehling versions) and ideal models. Good representation of solubility diagrams was obtained using partly readjusted UNIFAC parameters of Larsen version. Taking into account the large range of applicability of UNIFAC and the predictions of the activity coefficients for many other components in different classes of mixtures, we can conclude that the new experimental data for the systems mentioned in this work should be included in the database used by UNIFAC in order to evaluate better interaction parameters and to improve predictions.