Aller au menu Aller au contenu
Scientific life
Scientific life
Scientific life

> Scientific life > PhD thesis

LGP2 - Ph.D. thesis defended in 2022


June 17, 2022 - Materials, Mechanical, Civil Engineering, Electrochemistry
Posidonia waste valuation for the production of high added value bio-based materials
Evelyne MAURET, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Latifa BERGAOUI, Professor, INSAT, Tunisie ♦♦ Ramzi KHIARI, Researcher, ISET Ksar Hellal, Tunisie
This thesis aims to recover the waste of Posidonia oceanica through the production of bio-based nanomaterials with high added value. In this context, the focus is on cellulose micro/nanofibrils (CM/NF) which are very promising because of their good mechanical, optical and rheological properties. The major drawback of CM/NF production is the high energy consumption of the mechanical processes of fibrillation and microfibrillation. Thus, the objective of this research work is to produce cellulose micro/nanofibrils with a reduced environmental impact.
First, for microfibrillation, the ecological process of steam explosion (combined or not with TEMPO oxidation as chemical pretreatment) was studied. This was compared to conventional grinding for the production of high-quality bleached cellulose micro/nanofibrils.
Then, bleaching step and chemical pretreatments were eliminated in the CM/NF pathway production. During this second strategy, the use of steam explosion and twin-screw extrusion for fibrillation was elucidated (processes for alternative refining) to produce lignin-containing cellulose micro/nanofibrils (LCM/NF).
Finally, to improve the quality of the produced LCM/NF (due to the hydrophobic character of lignin), the application of lignin sulfonation was investigated (in situ steam explosion and as soft chemical pretreatment after the steam explosion). Compared to the conventional methods of CM/NF production, bleaching and chemical or enzymatic pretreatments could be successfully eliminated. Therefore, it is assumed that the quality of the product is different, providing different properties allowing their use in various fields. This strategy makes it possible to produce an economical and ecological material while taking into account the high efficiency of the processes, the limited use of chemicals and the low energy consumption during the production of LM/NFC.
Other members of the jury
Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Younès MOUSSAOUI, Professor, Université de Gafsa, Tunisia ♦♦ Gabriel PAËS, Research Director, INRAE, Reims ♦♦ Sami BOUFI, Professeur, Université de Sfax, Tunisia ♦♦ Nicolas BROSSE, Professor, Université de Lorraine

Andrea Estefania VERA LOOR

May 19, 2022 - Materials, Mechanical, Civil Engineering, Electrochemistry
Novel use of hydrogen peroxide to convert bleached kraft pulp into dissolving pulp and microfibrillated cellulose
Nathalie MARLIN, HDR Lecturer, Grenoble INP-Pagora / LGP2 ♦♦ Gérard MORTHA, Professor, Grenoble INP-Pagora / LGP2
The present study investigated the conversion of bleached Kraft pulp into dissolving pulp and microfibrillated cellulose using three oxidative treatments:
(1) the activation of hydrogen peroxide by copper species for the production of hydroxyl radicals;
(2) the combination of caustic extraction with hydrogen peroxide to remove hemicelluloses and to oxidize cellulose; and
(3) the oxidation by sodium periodate followed by hydrogen peroxide oxidation to enrich the pulp with carboxyl groups.
Dissolving pulps properties were hardly reached, but the treatments (1) and (3) enabled to produce interesting microfibrillated cellulose with reduced energy consumption.
Moreover, to evaluate the dissolution behavior, a derivatization method using cellulose tricarbanilation was developed. This simple method, based on particle size measurement by DLS, allows to discriminate cellulosic samples.
Other members of the jury
Dmitry EVTUGUIN, Professor, Universidade de Aveiro, Portugal ♦♦ Yahya HAMZEH, Professor, University of Tehran, Iran ♦♦ Christine CHIRAT, Professor, Grenoble INP-Pagora / LGP2


April 6, 2022 - Fluid Mechanics, Energetics, Processes
Integration of printed electronic capabilities on 2D and 3D thermoplastics for radiofrequency implementations
Nadège REVERDY-BRUAS, Associate Professor HDR, Grenoble INP-Pagora / LGP2 ♦♦ Tan Phu VUONG, Professor, Grenoble INP-Phelma / IMEP LAHC ♦♦ Denis CURTIL, Lecturer, Grenoble INP-Pagora / LGP2
This thesis is part of an Industrial Excellence Chair research program named MINT (innovating for molded & printed electronics), initiated in September 2015. MINT was supported by Grenoble INP Foundation and sponsored by Schneider Electric which has committed with two research laboratories, LGP2 and IMEP-LAHC, so that to develop electronic functionalities on 3D thermoplastics.
Goal of the thesis: to develop an additive manufacturing process in order to functionalize three-dimensional thermoplastics in the context of the Internet of Things and therefore, in the wireless field.
The thesis is structured around three axes. First, a bibliographic study details the molded interconnect device (MID) processes and a classification of these among the mastered 3D additive manufacturing technologies is proposed. Devices produced by MID process are presented for each of the areas covered.
Then, the Jetting process and its geometrical and electrical characterization are presented. Printing parameters are studied and optimization strategies for robust printing are implemented.
Finally, through a characterization of coplanar transmission lines in 2D and 3D, the radiofrequency performances of prints by Jetting are evaluated. 2D coplanar lines are simulated and printed. Process is optimized by printing mesh ground planes. Coplanar lines are also printed on 3D substrates with 90° and 130° angles and then measured. Radiofrequency applications are then detailed on 2D and 3D substrates such as a LoRa antenna, a RFID tag and a 5G antenna radome showing the potential applications of the technology developed in field of printed antenna on 3D objects.
Other members of the jury
Henry HAPPY, Professor, Université de Lille ♦♦ Fabien FERRERO, Professor, Université Côte d'Azur ♦♦ Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Mohamed SAADAOUI, Associate Professor, Mines Saint-Etienne ♦♦ Philippe PASSERAUB, Associate Professor, HEPIA Campus Biotech, Suisse ♦♦ Cécile VENET, Materials Resilience Stream Leader, Schneider Electric ♦♦ Manuel FENDLER, Mechatronics Platform Manager, CEA Tech Grand Est

Gloria Ifunanya NGENE

March 11, 2022 - Fluid Mechanics, Energetics, Processes
Coupling refining, chemical and enzymatic treatments for improved purification and dissolution of cellulose
Jean-Claude ROUX, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Dominique LACHENAL, Emeritus Professor, Grenoble INP-Pagora / LGP2
In this study, mechanical refining was used in conjunction with cold caustic extraction and xylanase treatments. The purpose was to increase the accessibility of chemical and enzymatic agents in the hard-to-reach regions of the fiber for more complete xylan extraction and to improve the reactivity of the pulp to dissolution.
The first part examined the morphological changes resulting from mechanical refining with three different technologies (Valley beater, PFI and pilot disc refiner) and the impact on the elimination of hemicelluloses when performing CCE and xylanase treatments. A good correlation between the modification of fibers induced by refining, namely the increase in the water retention value (WRV), the increase in the specific surface, the shortening of fibers, the generation of fines, and the CCE performance was found.  At a soda concentration of 100 g/L, the xylan removal for the Valley beater, PFI, and disc refined pulp were 84%, 82%, and 79%, respectively. This corresponds to 3.3%, 3.6%, and 4.3% residual xylan in the extracted pulp, starting from 20% in the reference paper pulp. Roughly, residual xylan was 50% less in refined pulp compared to unrefined pulp. In terms of upscaling, it was determined that though the laboratory refiners performed slightly better than the industrial-like refiner, the difference was marginal. Therefore, the risks associated with upscaling would be minimal in this process.
In order to further improve the CCE extraction performance, certain strategies were examined in the second part of this study. The most promising was to perform simultaneous refining / CCE with the Valley beater and the PFI refiners. The response of residual xylan in the pulp to simultaneous refining / CCE was already high at 60 g /L NaOH, with for example a xylan reduction of 79% for the Valley beater. This strategy makes it possible to achieve a good xylan extraction without formation of cellulose II
In the third part of this thesis, the influence of the hemicellulose elimination treatment on the reactivity of the resulting pulp was studied. Reactivity was evaluated on the basis of the degree of swelling in NaOH and dilute cupriethylene diamine solution (CUEN), the solubility in 8% NaOH at -10 ° C and the Fock measurement. The result obtained showed that hemicellulose removal strategies that included mechanical refining led to better pulp reactivity than unrefined pulp. The best result was obtained with the refined pulps extracted with 6% soda (no cellulose II formed in the pulp). In addition, we obtained a Fock reactivity ranging from 60 to 70% which exceeded that obtained for reference prehydrolysis kraft dissolving pulp . The good correlations found between swelling measurements, solubility in caustic soda, and Fock reactivity suggest that the tedious Fock test could be substituted by the much simpler swelling and solubility measurements.
In the last part of this study, the xylans recovered from the CCE treatment of unrefined and refined pulps at 6% and 10% NaOH concentrations were characterized. The average DPn ranged from 70 to 177. The DP of xylan extracted from the pulp after refining was higher than for the unrefined pulp.
In conclusion, the results obtained in this study show that the production of dissolving grade pulp from conventional hardwood kraft pulp is feasible with the use of existing technologies (refining, CCE). This represents a major advantage since a kraft pulp mill may easily shift from paper pulp to dissolving pulp production and vice versa, depending on the market conditions.
Other members of the jury
Gérard MORTHA, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Maria Angels PELACH, Professor, Universitat de Girona, Espagne ♦♦ Pierre-Yves PONTALIER, Associate Professor HDR, Toulouse INP - ENSIACET ♦♦ Stéphane GRELIER, Professor, Bordeaux INP - ENSCBP


March 1st, 2022 - Materials, Mechanical, Civil Engineering, Electrochemistry
Preparation of biobased materials from nano-polysaccharides and lignin particles for food packaging applications
Julien BRAS, Associate Professor HDR, Grenoble INP-Pagora / LGP2 ♦♦ Orlando J. ROJAS, Professor, University of British Columbia, Canada ♦♦ Bruno D. MATTOS, Post-doctoral fellow, Aalto University, Finland ♦♦ Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2
The goal of this project is to better understand the interactions between different biobased colloids. The three most abundant polymers that can be extracted from nature are cellulose, chitin, and lignin. Cellulose and chitin fibers can be mechanically fibrillated into colloidally stable nanofibers while lignin and wax (nano)particles can be prepared. These colloids have been studied individually however the interactions between each other have been so far overlooked. To create fully biobased materials, it is important to understand the colloids’ behavior but also their interactions. Moreover, these colloids are promising for food packaging applications. Cellulose and chitin nanofibers can act as matrices to make strong films with high oxygen barrier properties while lignin can form active particles that have antioxidant and UV absorbing properties and wax particules are hydrophobic.
The first part of the project focuses on the preparation of the colloids, in particular, chitin nanofibers (ChNF) from shrimp, fly or mealworm sources. Promising mechanical properties were obtained from films made from chitin and cellulose fibrillated together.
Then, a new method to prepare LP in the presence of cellulose or chitin nanofibers was studied. Electrostatic attraction between ChNF and LP led to homogeneous repartition of LP into ChNF films. Finally, we took advantage of the different colloids interactions to prepare multilayer films with promising high barrier properties including oxygen, water vapor, UV, and grease barriers.
This thesis brings some understandings on biobased colloids interactions and how to use these interactions to create fully biobased functional films towards barrier food packaging applications.
Other members of the jury
Alain DUFRESNE, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Aji MATHEW, Professor, Stockholm University, Sweden ♦♦ Véronique COMA, Associate Professor, Université de Bordeaux ♦♦ Susana DE MATOS FERNANDES, Associate Professor, Université de Pau et des Pays de l’Adour


February 9, 2022 - Materials, Mechanical, Civil Engineering, Electrochemistry
Formulation of a thermosetting biocomposite based on poly (furfuryl alcohol) and cellulose for 3D printing
Davide BENEVENTI, CNRS Research Director, Grenoble INP-Pagora / LGP2 ♦♦ Didier CHAUSSY, Professor, Grenoble INP-Pagora / LGP2
In the last two decades, additive manufacturing has emerged as a revolutionary and influential technology. Historically, stereolithography is the first technique used in 3D printing, later followed by other processes including direct ink writing. It makes it possible to print materials such as ceramics, cement pastes and, more recently, fossil-based thermosetting resins.
In a context where sustainable development is a key subject, this thesis focuses on the creation of a new biobased printable ink using the additive manufacturing approach. This ink is composed of a blend of bio-based furanic resin, cellulosic fillers and, eventually, carbon nanotubes. The thermosetting resin provides dimensional stability, the cellulose particles enable the tuning of the rheological properties and carbon nanotubes increase electrical conductivity.
First, the rheological requirements for a printable ink compatible with the direct ink writing technique, were studied and displayed a shear-thinning behavior and a yield stress superior to 105 Pa. Later the ensuing crosslinked composites were extensively characterized highlighting high thermomechanical stability permitting to reach a material processing temperature of up to 200°C. The DIW process and the curing step were thoroughly studied and optimized in order to obtain a better printing quality and excellent interlayer cohesion.
Finally, to overcome some challenges encountered during the printing of the paste, an in situ crosslinking strategy was implemented on a 3D printer designed as part of this thesis and equipped with a thermo-regulating printing chamber between 30°C and 250°C.
Other members of the jury
Christine CHIRAT, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Antoine LE DUIGOU, Associate Professor, Institut de Recherche Dupuy de Lôme, Lorient ♦♦ Alice MIJA, Professor, Université Côte d'Azur ♦♦ Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Roberta BONGIOVANNI, Professor, Politecnico di Torino, Italie ♦♦ Alessandro GANDINI, former University Professor

Loreleï DOUARD

January 28, 2022 - Materials, Mechanical, Civil Engineering, Electrochemistry
Surface modification of cellulose and nanocelluloses by innovative green processes
Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Julien BRAS, Associate Professor HDR, Grenoble INP-Pagora / LGP2
Nowadays, nanocelluloses are one of the priorities of the European bioeconomy, as evidenced by the numerous industrial investments in the field and the increase in the number of scientific journals published each year. The grafting of a chemical function on these nano-elements gives them new attractive functions, as shown by the development of anionic nanocelluloses.
However, the preparation of these materials, remains problematic when it comes to moving to an industrial scale for reasons of cost and/or toxicity of reagents and solvents. This is why acidic natural deep eutectic solvents (DES) and the principles of mechanochemistry were studied in this thesis work.
This study confirmed the possibility of extracting one-step functionalized cellulose nanocrystals (CNC) from two deep eutectic solvents composed of choline chloride with citric acid monohydrate or oxalic acid dihydrate with a 1 to 1 molar ratio. A design of experiment enabled the optimization of this process. Moreover, the cellulosic residues could be used to extract cellulose nanofibrils (CNF) in a biorefinery concept, thus transforming more than 95 % of the cellulosic fibres into nanocelluloses.
The impact of mechanochemistry on cellulosic materials has also been confirmed by degradation of crystallinity and degree of polymerization. This solvent-free and catalyst-free process allowed the esterification of cellulose nanocrystals, which has been proven by chemical characterization technics.
Finally, an innovative process made it possible to obtain functional cellulose nanocrystals with a very high yield.
Other members of the jury
Wim THIELEMANS, Professor, KU Leuven, Belgique ♦♦ Evelina COLACINO, Associate Professor, Université de Montpellier  ♦♦ Etienne FLEURY, Professor, INSA Lyon ♦♦ Evelyne MAURET, Professor, Grenoble INP-Pagora / LGP2


January 20, 2022 - Optics and Radiofrequencies
Development of Innovative and Transparent Radio-Frequency devices based on Nanocelluloses-Silver Nanowires hybrid system
Tan Phu VUONG, Professor, Grenoble INP-Phelma / IMEP LAHC ♦♦ Julien BRAS, Associate Professor HDR, Grenoble INP-Pagora / LGP2 ♦♦ Aurore DENNEULIN, Associate Professor, Grenoble INP-Pagora / LGP2
Telecommunications systems have evolved significantly in recent years to meet the requirements of the Internet of Things, smart buildings or packaging. These new devices require flexibility and transparency to facilitate their integration into every-day-life objects. Printed electronics, which implement functional inks by printing processes, make radiofrequency systems flexible and efficient. The recent development of transparent and conductive inks opens up new way of design and integration.
This thesis focuses on the development of passive and transparent radio frequency (RF) systems using printing processes such as screen printing. To achieve this objective, three strategies are proposed.
The first strategy consists in opening the design of the antenna (mesh) in order to let the light pass through the device. The mesh geometries of screen-printed dipole antennas were examined. A second study was carried out on the influence of the mesh opening on the optical and RF properties of Coplanar Waveguide (CPW) antennas.
The second strategy concerns the development of transparent conductive inks. Current commercial inks are too weakly electrically conductive to produce effective RF devices. When organized as a network, silver nanowires exhibit excellent conduction and transparency properties. According to recent work, placed in synergy with nanocellulose, a biosourced and renewable polymer, they make it possible to obtain promising optical and electrical properties in printed thin layers by screen-printing. The optimization of the formulation has made it possible to obtain a new conductive ink compatible with RF specifications with a surface resistance of 2 Ω.sq-1 for a transparency of 72 %.
Finally, the third strategy is based on the combination of the two previous strategies.
These promising results pave the way towards the integration of transparent RF devices for telecommunication, smart packaging or smart buildings.
Other members of the jury
Xavier CASTEL, Professor, Université de Rennes 1 ♦♦ Evangéline BENEVENT, Associate Professor, Aix-Marseille Université ♦♦ Ke WU, Professor, Polytechnique Montréal, Canada ♦♦ Aline ROUGIER, Research Director, CNRS ♦♦ Yves GROHENS, Professor, Université Bretagne Sud ♦♦ Dominique RAULY, Associate Professor, Université Grenoble Alpes ♦♦ Erika VANDELLE, Research Engineer, Thales ♦♦ Gaël DEPRES, Chief Central R&D Manager, Arjowiggins France

Date of update June 29, 2022

Université Grenoble Alpes