Khalid Lamnawar

Institut National des Sciences Appliquées de Lyon | INSA Lyon · Laboratory of Polymer Materials Engineering (IMP - UMR 5223)

The present work explores the shear and extensional rheology of immiscible multi-micro/nanolayered systems comprising low-density polyethylene (LDPE) paired with polystyrene (PS) and polycarbonate (PC) obtained from forced-assembly multilayer coextrusion. Firstly, miscible multilayer references based on LDPE/LLDPE layers were prepared with their mi...

Lattice structures nowadays have gained a peak in research. Inspired by the honeycomb structure and fishbone, this study investigated lattice structures that can provide auxetic behavior and store maximum energy absorption during deformation mode. From that, the study involved designing and producing different modified lattices based on the honeyco...

The colossal development of modern electronic devices has inevitably led to an increase in electromagnetic interference (EMI), which has gradually become the fourth most prevalent type of pollution in the world. It is therefore necessary to seek more effective EMI‐shielding materials to overcome the shortcomings of conventional metal‐based material...

The present work has aimed at gaining a deeper understanding of the effects of shear flow on the behaviors of nano fillers evolution inside linear and long chain branched polymer matrices. Accordingly, measurements consisting of transient start-up shear rheology coupled with small amplitude oscillatory sweep (SAOS) and dielectric tests were designe...

It is proverbial that the rheological properties of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are disparate because of their different molecular microstructures due to the unlike methods of polymerization. In this work, multiple characterizations including Size-Exclusion Chromatography (SEC) coupled with low-angle...

The objective of the present study was to investigate multiphase systems based on polylactic acid (PLA) and polyamide 11 (PA11) from blends to multilayers. Firstly, PLA/PA11 blends compatibilized with a multifunctionalized epoxide, Joncryl, were obtained through reactive extrusion, and the thermal, morphological, rheological, and mechanical behavio...

It is proverbial that the rheological properties of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are disparate because of their different molecular microstructures due to the unlike methods of polymerization. In this work, multiple characterizations including Size-Exclusion Chromatography (SEC) coupled with low-angle...

This paper investigates the biaxial stretchability of polylactic acid (PLA)/poly (butylene adipate co-terephthalate) (PBAT)/thermoplastic cereal flour (TCF) ternary blends with a PLA/PBAT ratio close to 60/40 and a constant TCF content. A twin-screw extrusion process was used to gelatinize the starch and devolatilize the water in order to obtain a...

The incorporation of bioactive and biocompatible fillers improve the bone cell adhesion, proliferation and differentiation, thus facilitating new bone tissue formation upon implantation. During these last 20 years, those biocomposites have been explored for making complex geometry devices likes screws or 3D porous scaffolds for the repair of bone d...

The aim of the present work was to investigate a 3D manufacturing process dealing with 3D Direct Pellet multi-Extrusion (DPPmE). Throughout this paper, various functionally graded materials (FGM) were obtained with tailored properties for bone regeneration. Therefore, an experimental investigation was performed to gain a better understanding of the...

The purpose of the present work was to gain a fundamental understanding of how the composition and physico-chemical properties affect the rheology, morphology, miscibility, and thermal stability of poly(lactic acid) (PLA)—poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) biopolymer blends obtained by melt mixing. First, restricted processing conditio...

The focus of the present paper is the rheological study of poly(D,L-lactic-acid) (PDLLA) towards a modeling of their healing properties during 3D direct pellet printing extrusion (DPPE). The viscoelastic properties of PDLLA and the filament temperature during deposition are first characterized. The influence of DPPE processing conditions is investi...

This study proposed a 3D-printed PEEK with a specific design to restore the damaged orbit shape. Such printed personalized implants are greatly affected by the process parameters, wherefore the effects of the nozzle temperatures, printing speed and layer thickness on the tensile properties were investigated based on the Taguchi approach. The optima...

This study proposed a 3D-printed PEEK with a specific design to restore the damaged orbit shape. Such printed personalized implants are greatly affected by the process parameters, wherefore the effects of the nozzle temperatures, printing speed and layer thickness on the tensile properties were investigated based on the Taguchi approach. The optima...

I am so glad to share with you our Special Issue entitled ‘Rheology and Processing of Polymers’, which covers the latest developments in the field of rheology and polymer processing, highlighting cutting-edge research focusing on the processing of advanced polymers and their composites [...]

In a circular economy context with the dual problems of depletion of natural resources and the environmental impact of a growing volume of wastes, it is of great importance to focus on the recycling process of multilayered plastic films. This review is dedicated first to the general concepts and summary of plastic waste management in general, makin...

To increase the lifetime of metallic molds and protect their surface from wear, a fluorinated ethylene propylene (FEP) polymer was coated onto a stainless-steel (SS304) substrate, using an air spray process followed by a heat treatment. The microstructural properties of the coating were studied using scanning electron microscopy (SEM) and energy-di...

Poly(L-lactide-co-D,L-lactide) PDLA/45S5 Bioglass® (BG) composites for medical devices were developed using an original approach based on a thermal treatment of BG prior to processing. The aim of the present work is to gain a fundamental understanding of the relationships between the morphology, processing conditions and final properties of these b...

Poly(methyl methacrylate) (PMMA)/polycarbonate (PC) laminates have been widely used as backboards for 5G cellphones where surface aesthetics are required. For this reason, the scratch behavior of the material is of particular interest. In the present work, the scratch behavior of alternating multi-layered PMMA/PC materials was studied by progressiv...

The interesting mechanical properties of polyether ether ketone give the material a place among the foremost competitors when it comes to replacing metal. Fused deposition modeling has been recognized as an alternative method to process polyether ether ketone parts. In this study, the effect of different process parameters such as nozzle, bed, and...

Phosphate ore slurry is a suspension of insoluble particles of phosphate rock, the primary raw material for fertilizer and phosphoric acid, in a continuous phase of water. This suspension has a non-Newtonian flow behavior and exhibits yield stress as the shear rate tends toward zero. The suspended particles in the present study were assumed to be n...

The present work deals with the 3D printing of multimaterials based on PLA/PMMA multilayers directly obtained from pellets. This polymer pair was chosen for their miscibility at the melt state and synergistic properties (i.e., to improve and weather tune the temperature resistance, transparency and thermomechanical properties of their PLA-based mat...

This paper deals with polyisobutylene (PIB) migration through post-consumer agricultural waste multilayer films based on four linear low-density polyethylene (LLDPE) matrices. Connections between shear, elongational rheology and tack surface properties were revealed for both model and recycled blends. The effects of aging time and temperature were...

Polylactic acid (PLA) can be a good alternative to petroleum-based polymers thanks to its organic origin and its biodegradability. This study introduces some promising routes for enhancing the processability of PLA, which presents several challenges due mainly to the poor shear and elongation properties of this biopolymer. To our knowledge, this is...

The present work deals with the 3D printing of multimaterials based on PLA/PMMA multilayers directly obtained from pellets. This polymer pair was chosen for their miscibility at the melt state and synergistic properties (i.e., to improve and weather tune the temperature resistance, transparency and thermomechanical properties of their PLA-based mat...

Continuous Glass Fiber-Reinforced Thermoplastic Composites (GFRTC) were successfully prepared using two different routes: a reactive laboratory-created approach as well as a compression molding method. Two kinds of high-performance polyphtalamides (PPA) were studied: PPA from a chain extension reaction of its parent prepolymer (named R-PPA) in comp...

This paper describes a future-oriented approach for the valorization of polyethylene-based multilayer films. The method involves going from eco-design to mechanical recycling of multilayer films via forced assembly coextrusion. The originality of this study consists in limiting the number of constituents, reducing/controlling the thickness of the l...

The multilayer coextrusion process is known to be a reliable technique for the continuous fabrication of high‑performance micro-/nanolayered polymeric products. Using laminar flow conditions to combine polymer pairs, one can produce multilayer films and composites with a large number of interfaces at the polymer-polymer boundary. Interfacial phenom...

It is known that copolymers are critical in modifying interfaces of multilayered polymeric products. However, not much is known about the influence of the macromolecular architecture of copolymers on the interfacial morphology evolution, viscoelasticity, and processability of layered systems. Therefore, we demonstrate the role of macromolecular arc...

Supramolecular zwitterionic silicones are synthesized by aza‐Michael reaction between acrylic acid and amine‐functional polydimethylsiloxanes. The in‐depth characterization of this chemistry, applied for the first time to silicones, is investigated first with model alkylamines (hexylamine, 2‐ethylhexylamine and N‐propylethylenediamine), a model oli...

Carbon fiber reinforced polycarbonate (CF/PC) composites have attracted attention for their excellent performances. However, their performances are greatly affected by environmental factors. In this work, the composites were exposed to hydrothermal aging to investigate the effects of a hot and humid environment. The mechanical properties of CF/PC c...

An understanding of the structural evolution in micro-/nano-layer co-extrusion process is essential to fabricate high-performance multilayered products. Therefore, in this work, we reveal systematically the multiscale structural development, involving both the layer architecture and microstructure within layers of micro-/nano-layer coextruded polym...

This paper is dealing with the polyisobutylene (PIB) migration phenomenon through the post-consumer agricultural waste multilayer films based on four linear low-density polyethylene (LLDPE) matrices. Through this work, a bridge between shear, elongational rheology, and tack surface properties was revealed on both model and recycled blends. Hereto,...

Multilayered polymer films are increasingly used in the daily life, but their macroscopic properties are always limited by the layer–layer interfacial compatibility. In this work, the influence of interface modification through in situ layer–layer interfacial reaction during a multilayered assembly is revealed from micro‐ to nanolayer films, based...

Continuous Glass Fiber-Reinforced Thermoplastic Polymers (GFRTP) were successfully prepared using two different routes: a reactive laboratory-created approach as well as a compression molding method. Two kinds of high-performance polyphtalamides (PPA) were studied: PPA from a chain extension reaction of its parent prepolymer in comparison with a vi...

In this work, a High Temperature hybrid process coupling “reactive Extrusion” and “Resin Transfer Molding” (HT-ERTM) was designed for the manufacturing of continuous Glass Fiber-Reinforced Thermoplastic Composites (GFRTC) with an elevated glass transition temperature. Hereto, a high performance polyphtalamide (PPA) obtained from the chain extension...

In this paper, a brief state of the art is given firstly on structure-processing-properties relationships on PLA. Secondly, a specific focus is devoted on some recent and not yet unpublished recent work regarding the isothermal and non-isothermal crystallization behaviors of the poly (lactic acid). Thereby, they were investigated by differential sc...

Shear and elongation rheology have been used in order to quantify the interfacial tension properties of PLA_PBAT blends. A multi-functional epoxide (Joncryl) has been chosen as a compatibilizer. From small amplitude oscillatory shear (SAOS), the results show that the addition of the Joncryl into the blends increased largely the shear rheological pr...

It is known that the macroscopic properties of multilayer polymer films are largely dominated by the diffuse interphase formed via interfacial diffusion between neighboring layers. However, not much is known about the origin of this effect. In this work, we reveal the role of interfacial diffusion and the diffuse interphase development in multilaye...

In the industry of polymer coextrusion processing, efforts are being made towards a better control of multilayer flow stability that is governed by the interface/interphase between neighbouring layers, the understanding of which is considerably inadequate. This study aims to explore the relaxation dynamics of polymer chains located in the interphas...

The main objective of this work was an experimental investigation making it possible to monitor, as well as achieve a deeper understanding of, the structural evolution of polyamide-6 as a thermoplastic-based composite matrix. Polyamide-6 from anionic ring-opening polymerization (AROP) of ε-caprolactam was chosen as a model matrix. Throughout this w...

The goal of this work is to develop study and characterize the structural evolution of thermoplastic matrix during the thermoplastic Resin Transfer Molding process. To attain this objective, the reaction kinetic and its properties for forming process of PA-matrix were investigated as an alternative for the production of thermoset systems. Through t...

In this work, hybrid process coupling “Reactive Extrusion” and “Resin Transfer Molding” machine (T-ERTM) equipped with an instrumented mold was designed and developed. Polyamides model matrix according to two kinds of polymerizations were studied as well anionic and chain extension reactions. For the former, different ratios of catalyst and activat...

The purpose of the present work is to develop a new biomaterial with suitable melt strength, stiffness-to-toughness balance, and the required thermal performance for food packaging applications. The study is dedicated to investigating a new physical compatibilization approach of biosourced materials as well poly (lactic acid) (PLA) and polyamide 11...

Biocomposites from polylactic acid (PLA) and olive solid waste (OSW) were melt-blended with core–shell acrylate rubber particles (ACR) in order to enhance the thermal stability upon melt processing and the mechanical performances of these biocomposites, thereby expanding their area of application. Dynamic mechanical analysis indicated that the ACR...

Influence of an in situ reactive interphase composed of graft copolymer on the melt shear and extensional rheology was systematically studied with a model bilayer of polyamide-6 (PA6)/maleic anhydride grafted poly(vinylidene fluoride) (PVDF-g-MAH). Firstly, small-amplitude oscillatory shear was used in situ to probe the development of reactive inte...

We provide rheological and dynamic insights into the role of an in situ reactive interphase with graft copolymers in multilayered polymer systems, using a polyamide-6 (PA6)/maleic anhydride grafted poly(vinylidene fluoride) (PVDF-g-MAH) bilayer as a model. Firstly, the influence of the reactive interphase on macroscopic melt flow behavior was studi...

A new valorization strategy for Olive Solid Waste (OSW) has been carried out consisting in incorporating this biomass as filler in a biopolymer matrix. In this study, biocomposites based on poly(d,l-lactide) (PLA) and OSW fillers were prepared with various filler contents. It was highlighted that the inclusion of OSW under high temperatures resulte...

The objective of this study was to gain a deep understanding of composition and compatibilization effects on the properties of entirely sustainably sourced polymer blends based on polylactide (PLA) and polyamide 11 (PA11). Generally, PLA cannot challenge regular commodity polymers due to its weak thermo-mechanical properties and its poor elongation...

An effort was made to demonstrate the dynamic heterogeneity of poly(methyl methacrylate) (PMMA)/poly(vinylidene fluoride) (PVDF) blends, where its composition dependence and the role of interphase were probed. Firstly, the composition dependence of thermorheological complexity of PMMA/PVDF blends in the melt was revealed. The molecular entanglement...

This work aims to examine whether or not interfacial failure can occur in a compatible polymer bilayer system under large shear and elongation deformations, as well as to probe the sensitivity of nonlinear transient rheology to the presence of interface/interphase at neighboring layers. For this, stress relaxation after a step strain and fast start...

Several polymers can be combined in one multilayer structure by reactive coextrusion. Tie-layers are often used to compatibilize adjacent layers and may reduce or suppress interfacial instabilities and defects in multilayer coextrusion flow. However, a new additional defect defined as " grainy " defect can be observed. In our best of knowledge, no...

This paper deals with the study of new interfacial instabilities, called “grainy” defects, in coextrusion process of reactive multilayer polymers. The main objective was to better understand this phenomenon since no help can be found in the literature. The fundamental approach from a micro-scale to a macro-scale involves the study of relationships...

Fundamental studies have been devoted to the interfacial phenomena at multilayered systems based on two model compatible polymers of PVDF and PMMA with varying molar masses. Linear and nonlinear rheology are demonstrated to be sensitive to the presence of diffuse interphase triggered at polymer/polymer interface. Firstly, the interdiffusion kinetic...

This study was dedicated to the blown film extrusion of poly(lactic acid), which mainly presents poor shear and elongation viscosities, and its blends. In order to enhance its melt strength, two main routes were selected (i) a structural modification through chain extension and branching mechanisms by adding a reactive multifunctional epoxide (name...

This work aims to investigate the growth and structural evolution of a diffuse interphase generated in a flow field and to highlight its importance on controlling the final properties of compatible multilayer materials. The model polymers chosen are poly(methyl methacrylate) (PMMA) and poly(vinylidene fluoride) (PVDF). Interdiffusion kinetics, geom...

Shear step strain experiments with various strain amplitudes have been performed on poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) melts using both stress-controlled and strain-controlled rheometers. Firstly, the onset of the rheological nonlinearity, i.e., nonlinear stress damping behavior, occurring after a large step strai...

A process for preparing a composite material comprising a bioresorbable polymer matrix and modified particles of biocompatible glass is described. The process comprises mixing modified particles of biocompatible glass with the constituent polymer(s) of the bioresorbable polymer matrix so as to obtain a homogeneous mixture. The mixture is then heate...

This supporting information presents several parts backing up the discussions in the text. It includes, among many others, the relaxation behavior, the morphological properties of the studied blends, and the fit or failure of the emulsion models (Palierne, Bousmina and Dickie) together with experimental results.  Part A-Relaxation behavior To quan...

The focus of this paper was to gain a true understanding of the impact of a multifunctional epoxide (Joncryl®ADR-4368) on the interfacial properties of biopolymer blends based on poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT). The effect of Joncryl on the shear rheological, morphological, and interfacial properties of th...

Modified Poly (lactic acid) (PLA) and Polybutylene adipate co- Terephthalate (PBAT) blends were prepared through mixing in a laboratory scale twin-screw extruder. Various concentrations of a multifunctionalized epoxy, acting as chain extender and a branching agent, were used. Rheological investigations of the prepared modified blends revealed highe...

The blown extrusion of poly(lactic acid) (PLA) presents several challenges mainly due to the poor shear and elongation properties of this biopolymer. This article highlights some promising routes to enhance the proc-essability of PLA for blown extrusion. To achieve this objective, various formulations of PLA with multifunc-tionalized epoxy, nucleat...

The blown extrusion of poly(lactic acid) (PLA) presents several challenges mainly due to the poor shear and elongation properties of this biopolymer. This article highlights some promising routes to enhance the proc-essability of PLA for blown extrusion. To achieve this objective, various formulations of PLA with multifunc-tionalized epoxy, nucleat...