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Purpose The purpose of this study is to test a flexible polymer with different characteristics compared to other classical polymers mostly used in the additive manufacturing process, and to improve its mechanical properties and... more
Purpose The purpose of this study is to test a flexible polymer with different characteristics compared to other classical polymers mostly used in the additive manufacturing process, and to improve its mechanical properties and microstructure, by modifying different printing parameters, to make it more suitable for various industrial applications. Design/methodology/approach Seven parameters were tested, namely, nozzle temperature, bed temperature, layer thickness, printing speed, flow rate, printing time gap between two successive printed layers and raster orientation. Rheological characterizations were conducted to evaluate the influence of nozzle temperature on the melt viscosity of thermoplastic polyurethane (TPU). The effect of thermal printing parameters on the crystallinity behavior was explored. Tomographic characterizations were realized to measure the porosity and evaluate the internal structure quality of printed specimens. Findings Increases of the nozzle temperature, be...
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L’objectif principal de ce travail a ete d’etudier l’effet de traitements enzymatiques et/ou chimiques sur les fibres de lin utilisees comme renfort dans un reseau polyester insature. Le traitement a la pectate lyase applique sur des... more
L’objectif principal de ce travail a ete d’etudier l’effet de traitements enzymatiques et/ou chimiques sur les fibres de lin utilisees comme renfort dans un reseau polyester insature. Le traitement a la pectate lyase applique sur des fibres de lin vert a permis d’obtenir des fibres ayant des proprietes mecaniques superieures a celles des fibres de lin roui. Ces differences ont pu etre expliquees par la composition polysaccharidique des fibres. Parmi les traitements chimiques utilises, celui au styrene a permis de diminuer le caractere hydrophile des fibres de lin roui ; le traitement au silane (g-MPS) a ameliore les proprietes mecaniques de ces fibres. Les proprietes mecaniques des materiaux composites reseau polyester/fibres de lin traitees sont ameliorees avec le traitement enzymatique et un accroissement des proprietes barriere est obtenu avec les traitements chimiques styrene et silane.
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Implanting scaffolds designed for the regeneration or the replacement of bone tissue damaged by diseases and injuries requires specially designed biomaterials that promote cell adhesion. However, the biodegradation rate of these scaffolds... more
Implanting scaffolds designed for the regeneration or the replacement of bone tissue damaged by diseases and injuries requires specially designed biomaterials that promote cell adhesion. However, the biodegradation rate of these scaffolds based on a single material is uniform. Four-dimensional printing appears to be a promising method to control this aspect by changing the shape and/or the intrinsic properties of 3D-printed objects under the influence of external stimuli. Two main classes of biomaterials and biocomposites based on biopolyesters, namely poly(lactic acid) (PLA) and poly(caprolactone) (PCL), were used in this study. Each of them was mixed with the inorganic filler hydroxyapatite (HA), which is a component of natural bone. The biocomposites and biomaterials were prepared using the melt extrusion process and then shaped using a 3D printer. Three-dimensional specimens showed a decrease in elongation at break and breaking strain due to variations of crystallinity. The crys...
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ABSTRACT In progress.
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ABSTRACT The influence of the incorporation of nanoparticles (organo-modified montmorillonite Cloisite 30B) in polyamide 6 (PA6) on the transport of small molecules was investigated. Nanocomposites were prepared by melt blending followed... more
ABSTRACT The influence of the incorporation of nanoparticles (organo-modified montmorillonite Cloisite 30B) in polyamide 6 (PA6) on the transport of small molecules was investigated. Nanocomposites were prepared by melt blending followed by cast extrusion for obtaining film-forming materials. The nanoclay content of the materials was varied from 0 to 5 vol%. Differential scanning calorimetry measurements, electronic microscopy, X-ray diffraction, and rheology were used for characterizing the nanocomposite structure. Because of the presence of nanofillers, a high barrier effect to nitrogen and water was clearly evidenced and mainly attributed to the increase of tortuosity because of the increase of the diffusion pathway generated by impermeable nanofillers. In this study, the high barrier effect was attributed to the very good dispersion of montmorillonite platelets in the PA6 matrix resulting from a two-step melt processing. This peculiar processing has induced a good exfoliation and an orientation parallel to the film surface of lamellar montmorillonite platelets which is clearly demonstrated from transmission electron microscopy analysis. The permeation results were evaluated on the basis of geometrical models proposed by Nielsen and Bharadwaj, and by analyzing the plasticization phenomenon in the case of water permeation involving a concentration-dependence diffusivity correctly approached by an exponential law.
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Research Interests: Materials Science, Kinetics, Medicine, Multidisciplinary, Adsorption, and 15 moreInfrared spectroscopy, Diffusion, Contact angle, Sorption, Maleic Anhydride, Surface treatment, Surface Properties, STEAM, Surface Energy, Flax, Chemical Treatment, Mechanical Processes, Chemical Modification, Mechanical Property, and Bioresource technology
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The standard polylactic acid (PLA), as a biodegradable thermoplastic polymer, is commonly used in various industrial sectors, food, and medical fields. Unfortunately, it is characterized by a low elongation at break and low impact energy.... more
The standard polylactic acid (PLA), as a biodegradable thermoplastic polymer, is commonly used in various industrial sectors, food, and medical fields. Unfortunately, it is characterized by a low elongation at break and low impact energy. In this study, a thermoplastic copolyester elastomer (TPCE) was added at different weight ratios to improve the impact resistance of PLA. DSC analysis revealed that the two polymers were immiscible. A good balance of impact resistance and rigidity was reached using the formulation that was composed of 80% PLA and 20% TPCE, with an elongation at break of 155% compared to 4% for neat PLA. This new formulation was selected to be tested in a fused filament fabrication process. The influence of the nozzle and bed temperatures as printing parameters on the mechanical and thermal properties was explored. Better impact resistance was observed with the increase in the two thermal printing parameters. The crystallinity degree was not influenced by the variat...
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The standard polylactic acid (PLA), as a biodegradable thermoplastic polymer, is commonly used in various industrial sectors, food, and medical fields. Unfortunately, it is characterized by a low elongation at break and low impact energy.... more
The standard polylactic acid (PLA), as a biodegradable thermoplastic polymer, is commonly used in various industrial sectors, food, and medical fields. Unfortunately, it is characterized by a low elongation at break and low impact energy. In this study, a thermoplastic copolyester elastomer (TPCE) was added at different weight ratios to improve the impact resistance of PLA. DSC analysis revealed that the two polymers were immiscible. A good balance of impact resistance and rigidity was reached using the formulation that was composed of 80% PLA and 20% TPCE, with an elongation at break of 155% compared to 4% for neat PLA. This new formulation was selected to be tested in a fused filament fabrication process. The influence of the nozzle and bed temperatures as printing parameters on the mechanical and thermal properties was explored. Better impact resistance was observed with the increase in the two thermal printing parameters. The crystallinity degree was not influenced by the variat...