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LGP2 - Ph.D. thesis defended in 2015

Claire MONOT

December 18, 2015 - Fluid Mechanics, Energy, Processes [Thesis online]
Ph.D. title
Contribution to the study of lignin-carbohydrate complexes (LCCs) in wood. Study of the impact of the different steps of a sulfur-free biorefinery process on these LCCs
Supervision
Christine CHIRAT, Associate Professor, Grenoble INP-Pagora / LGP2
Abstract
The valorization of lignocellulosic biomass is nowadays a major issue due to the reduction of fossil resources. Separating each component to valorize them the best way possible is the goal of the pulp and paper biorefineries. The effluent of the mill, called the black liquor, is currently burnt to produce energy, but gasification would increase the energy efficiency. For this, a sulfur-free cooking of wood is necessary, as sulfur inhibits gasification.
Therefore this study first focused on the feasibility of cooking without sulfur, which is more difficult than a conventional kraft cooking containing sulfur. The work was done on softwood which is more difficult to delignify than hardwood. The wood was first pretreated with an autohydrolysis to remove hemicelluloses for further valorization.
The results were conclusive for the production of cellulose for textile applications. To explain the fact that the autohydrolysed wood was easier to delignify than the control wood with kraft and soda cooking, structural differences of wood components were looked for. Lignin did not show major differences whether the wood was prehydrolyzed or not, whereas the complexes between lignin and carbohydrates (LCCs) showed significant differences, which could explain the results obtained.
Other members of the jury
Nicolas BROSSE, Professor, Université de Lorraine, France ♦♦ Ana Paula DUARTE, Professor, Universidade da Beira Interior, Portugal ♦♦ José Carlos DEL RIO, Professor, Instituto de Recursos Naturales y Agrobiologia de Sevilla, Spain ♦♦ Dominique LACHENAL, Professor, Grenoble INP-Pagora / LGP2, France

Benoît ARNOUL-JARRIAULT

December 17, 2015 - Fluid Mechanics, Energy, Processes [Thesis online]
Ph.D. title
Hemicellulose extraction of paper grade pulp for dissolving pulp production
Supervision
Dominique LACHENAL, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Christine CHIRAT, Associate Professor, Grenoble INP-Pagora / LGP2
Abstract
Dissolving pulps, which are composed of 95% cellulose, are the raw materials for the production of regenerated cellulose fibers for textile application and for the production of cellulose derivatives. These products are alternatives to oil based materials. A growing demand in such products is expected in the next decades. Therefore, additional capacities in the production of wood dissolving pulp must be created.
The purpose of this work is to develop hemicellulose removal processes with the aim to convert a softwood kraft paper pulp into a dissolving pulp. Three extraction methods were tested: A cold caustic extraction process (CCE) performed under conventional and unconventional conditions; A process consisting in an acid stage at high temperature (up to 150°C) followed by a hot caustic extraction (A-HCE); An enzymatic hydrolysis using xylanase, mannanase, and cellulase.
Conversion was quite successful with the two first processes. However, 100% of hemicellulose removal was never reached. In order to improve the hemicellulose extraction efficiency, several pre-treatments were tested (refining, steam explosion, TEMPO oxidation). The addition of a refining stage allowed for a reduction of the NaOH concentration during CCE extraction without affecting the hemicellulose extraction efficiency.
The last part of this thesis work focused on the dissolving pulp swelling. A new and rapid test for the characterization of fiber swelling was developed. This method was used as an approach to the assessment of dissolving pulp reactivity in the viscose process in place of the Fock's method.
Other members of the jury
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Florian MARTOÏA

November 30, 2015 - Materials, Mechanical, Civil Engineering, Electrochemistry [Thesis online]
Ph.D. title
Nanocomposites and foams from cellulose nanofibrils: rheology during their processing and mechanical properties
Supervision
Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Pierre DUMONT, Professor, INSA Lyon ♦♦ Laurent ORGÉAS, CNRS Research Director, Laboratoire 3SR, Grenoble
Abstract
This study focuses on the use of cellulose nanofibrils (NFCs) as bio-based nano-reinforcement in polymer composites and foams. These renewable materials can be used in place of traditional materials such as for instance to produce sandwich panels. This experimental, theoretical and numerical work aims at optimizing the processing of these NFC-based materials as well as their use properties.
In the first part of this work, the rheology of concentrated NFC suspensions, that behave as thixotropic yield stress fluids, is investigated at macro- and mesoscales using an original rheo-ultrasonic velocimetry (rheo-USV) setup allowing the local flow kinematic to be obtained. We show that the flow of NFC suspensions is highly heterogeneous and exhibits complex situations with the coexistence of wall slippage, multiple shear bands and plug-like flow bands. Using this experimental database, we develop an original multiscale rheological model for the prediction of the rheology of NFC suspensions. The model takes into account the anisotropic fibrous nature of NFC networks as well as colloidal and mechanical interaction forces occurring at the nanoscale. The model predictions prove that colloidal and hydrodynamic interaction forces together with the orientation and the wavy nature of NFCs play a major role on the yield stress and shear thinning behaviour of the suspensions.
In the second part of this work, NFC-reinforced polymer nanocomposite films are processed for a wide range of NFC contents. Using advanced microscopy techniques (AFM, SEM), X-ray diffraction and mechanical tests (tensile and DMA tests), we show that NFCs form highly connected nanofibrous structures with in-plane random orientation, that these connected NFC networks play a leading role on the mechanical behaviour of the nanocomposites and that the elastic properties of nanocomposite films are much lower than those predicted from the micromechanical models of the literature. In light of these observations, we propose an alternative multiscale model in which the main involved deformation nano-mechanisms are those occurring both in the amorphous segments of the nanofibers and in the numerous nanofiber-nanofiber contact zones.
Finally, in a third part, we focus on the influence of the processing conditions, the suspension type and the NFC concentration on the microstructure (using X-ray synchrotron microtomography), the mechanical properties (using compression tests) and the deformation micro-mechanisms (using in situ compression test with X-ray microtomography) of various foams prepared from NFC suspensions by freeze-drying.
Other members of the jury
Tatiana BUDTOVA, Research Director, Mines ParisTech ♦♦ Guillaume OVARLEZ, CNRS Research Director, Université de Bordeaux ♦♦ Jean-Yves CAVAILLÉ, Professor, INSA Lyon ♦♦ Véronique MICHAUD, Professor, EPFL, Switzerland ♦♦ Jean-Luc PUTAUX, CNRS Research Director, Cermav, Grenoble

Marion HUET

November 24, 2015 - Fluid Mechanics, Energy, Processes [Thesis online]
Ph.D. title
Black liquor valorization by hydrothermal processes for energetic and green chemistry purposes.
Supervision
Dominique LACHENAL, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Anne ROUBAUD, Research Engineer, CEA
Abstract
This thesis aims to study sulfur free black liquor valorization through two hydrothermal processes: supercritical water gasification and hydrothermal liquefaction. These processes will be compared to the industrial process (evaporation and Tomlinson boiler) with three mains criteria: energetic yield, sodium recovery and phenolic molecules production.
In supercritical conditions, gas formation is competitive with char formation. Fast heating and high temperature permit to increase gas yield, thus energetic yield. However, conversion of phenolic compounds from lignin is low below 500°C, leading to a lower energetic yield than reference. In a continuous process, at high temperatures (700°C) and fast heating, energetic yield should be two times higher than industrial process (simulation at thermodynamic equilibrium). Wood prehydrolysis and softwood lead to a lower conversion of black liquor.
Hydrothermal liquefaction produces a biocrude which can be burnt and phenolic platform compounds. Indeed, lignin is depolymerized into reactive fragments which can be degraded into platform phenolic molecules. Moreover, the recombination of these fragments, leading to biocrude formation, is favored by the carbohydrates derivatives in black liquor. Wood prehydrolysis and hardwood lead to better energetic and phenolic molecules yields.Sodium recovery is satisfactory for both processes. Substitution of Tomlinson recovery by a hydrothermal process is then possible.
Other members of the jury
Maria Jose COCERO, Professor, University of Valladolid, Spain ♦♦ Nicolas BROSSE, Professor, Université de Lorraine, France ♦♦ Frédéric VOGEL, Professor, Institut Paul Scherrer, Switzerland ♦♦ Christine CHIRAT, Associate Professor, Grenoble INP-Pagora / LGP2 ♦♦ Elsa WEISS-HORTALA, Assistant Professor, École des Mines d'Albi-Carmaux, France

Seema SAINI

November 13, 2015 - Materials, Mechanical, Civil Engineering, Electrochemistry
Ph.D. title
Surface modification of cellulose nanofiber to impart active properties for packaging.
Supervision
Julien BRAS, Associate Professor, Grenoble INP-Pagora / LGP2 ♦♦ Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2
Abstract
The present investigation has developed efficient green strategies for the chemical modification of cellulose nanofibers (CNF) in order to impart antimicrobial activities. Seven different functionalized CNF were produced in this context keeping in mind sustainability and industrial feasibility within new generation packaging field.
First, CNF were designed with cyclodextrin to control the release of natural active molecules. In other strategies, non-leaching contact active antimicrobial surfaces were prepared using natural active molecules or following biomimetic approaches. Results are very promising and allow obtaining efficient antimicrobial surface without any release. High level characterizations confirm surface grafting (e.g. XPS, QCM-D, NMR) and antimicrobial efficiency (S.aureus, E.Coli).
One of the best strategies using antibiotic grafted CNF was produced at lab scale and also implemented at semi-industrial scale. The final idea was to produce medical packages limiting the cross contamination in hospitals.
Other members of the jury
Graziano ELEGIR, Researcher, Innovhub-SSI, Italy ♦♦ Lars WÅGBERG, Professor, KTH Royal Institute of Technology, Sweden ♦♦ Véronique COMA, Associate Professor, Université de Bordeaux ♦♦ Elisa ZENO, Researcher, Centre Technique du Papier, Grenoble

Karima BEN HAMOU

October 24, 2015 - Materials, Mechanical, Civil Engineering, Electrochemistry [Thesis online]
Ph.D. title
Extraction of structure and properties controlled cellulose nanofibrils: characterization, rheological and nanocomposites applications.
Supervision
Alain DUFRESNE, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Hamid KADDAMI, Professor, Faculty of Science and Technology Marrakech (Morocco)
Abstract
The cellulose nanofibrils (CNF), obtained by TEMPO oxidation of native cellulose microfibrils as colloidal aqueous suspensions, are biosourced nanoparticles having rheological and optical properties well adapted for the conception of new nanomaterials with high performance.
The main purpose of this study was to control and optimize the conditions for preparing these NFCs extracted from date palm tree by examining the oxidation time and the number of passes through the homogenizer. The success of the reaction was demonstrated by FT-IR spectroscopy. The rate of the carboxylic groups has been calculated by conductometric titration and ranged between 221 and 772 mol / g of anhydroglucose. Morphological studies show that oxidized CNFs are very individualized by introducing negative charges on their surfaces that induce electrostatic repulsion forces between the fibrils. Particular attention has been given to the viscoelasticity of oxidized-TEMPO CNF suspensions whose monitoring was carried out by a rheometer ARES-G2TA.
These nanocharges were incorporated in a thermoplastic (PVAc) and nanocomposite materials obtained were characterized by SEM, TGA, DSC, DMA and mechanical testing.
Other members of the jury
Larbi BELACHEMI, Professor, Faculty of Science and Technology Marrakech (Morocco) ♦♦ Étienne FLEURY, Professor, INSA de Lyon ♦♦ Youssef HABIBI, Researcher, Luxembourg Institute of Science and Technology (Luxembourg) ♦♦ Abdelhakim ALAGUI, Professor, Faculty of Science Semlalia Marrakech (Morocco)

Pedro Maximiano RAIMUNDO

October 14, 2015 - Fluid Mechanics, Energy, Processes
Ph.D. title
Analysis and modeling of the local hydrodynamics in bubble columns.
Supervision
Alain CARTELLIER, CNRS Research Director, LEGI ♦♦ Davide BENEVENTI, CNRS Researcher, Grenoble INP-Pagora / LGP2
Abstract
Bubble columns reactors are widely used in chemical and biological engineering due to their simple configuration with no mobile parts. However, the scale-up rules for such bubble column reactors is still a quite challenging process. In particular, using two-fluid approaches, the current practice relies on an ad-hoc fitting of the bubble size with the column dimension.
To progress in the up-scaling of bubble columns hydrodynamics, experiments have been achieved over a wide range of parameters, with columns diameters from 0.15 to 3m and with gas superficial velocities from 3 to 35cm/s, yielding void fractions up to 35%. To ensure comparable hydrodynamic conditions, almost identical bubble size distributions were produced for all these conditions. In the same spirit, coalescence was blocked. A battery of measuring techniques has been exploited including phase detection optical probes, endoscopic imaging and Pavlov tubes. A new technique has also been developed that provides the mean horizontal diameter of bubbles. That method, which is based on the spatial correlation of the signals from two optical probes located side by side, has been validated in strongly agitated, unsteady bubbly flows at high void fractions.
The database collected on the radial and axial evolutions of local hydrodynamics properties (gas hold-up, bubble size, phasic velocities and their fluctuations…) has led to a clarification of the scaling laws for such systems. In particular, we have shown that the auto-similarity of the flow structure in heterogeneous conditions leads to an entrained liquid flow rate that growths with the column diameter as D2 (gD)1/2. In other words, the entrainment capability of a bubble column is only set by the column size and does not depend on the injected gas superficial velocity. Further more, the heterogeneous character of the flow has been shown to originate from strong concentration gradients that define meso-scale structures: the resulting collective dynamics has a profound impact on the mean relative velocity between phases. Inspired by Simonnet et al. (2008), that dynamics can be well represented by introducing a swarm factor in the drag law. With such an approach, 3D URANS two-fluid simulations become able to reproduce without any ad-hoc adjustment the scale effect observed over the whole range of flow conditions considered here.
Other members of the jury
Evelyne MAURET, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Dominique LEGENDRE, Professor, Université de Toulouse III ♦♦ Romain VOLK, Associate Professor, ENS de Lyon ♦♦ Daniele MARCHISIO, Professor, Politecnico di Torino, Italie ♦♦ Claude DANIEL, Research Engineer, Solvay ♦♦ Frédéric AUGIER, Research Engineer, IFP Energies nouvelles ♦♦ Ann FORRET, Research Engineer, IFP Energies nouvelles

Oleksandr NECHYPORCHUK

October 2, 2015 - Materials, Mechanical, Civil Engineering, Electrochemistry [Thesis online]
Ph.D. title
Cellulose nanofibers for the production of bionanocomposites
Supervision
Ana Maria BOTELHO DO REGO, Associate Professor, Instituto Superior Técnico (Portugal) ♦♦ Frédéric PIGNON, CNRS Research Director, Laboratoire Rhéologie et Procédés, Grenoble ♦♦ Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2
Abstract
One of the main challenges in the context of biocomposites development is to replace petroleum-based materials with bio-based. Because of their natural origin, relatively high strength and the ability to form transparent products, cellulose nanofibers have a large potential for application in the composite materials.
This work was focused on the optimization of cellulose nanofiber production methods using biochemical and mechanical treatments. Then, the rheological and structural properties of these nano-elements in aqueous media were investigated. Finally, the production of latex-based composites was carried out. The questions of homogeneous dispersion of cellulose nanofibers in the matrix and the interactions between these two components were particularly addressed.
Other members of the jury
Étienne FLEURY, Professor, INSA de Lyon ♦♦ Alain PONTON, CNRS Research Director, Université Paris Diderot ♦♦ Ana Paula DUARTE, Professor, Universidade da Beira Interior (Portugal) ♦♦ Albert MAGNIN, CNRS Research Director, Université Grenoble Alpes ♦♦ Amelia ALMEIDA, Auxiliary Professor, Instituto Superior Técnico (Portugal)

Besma BERRIMA

September 28, 2015 - Fluid Mechanics, Energy, Processes [Thesis online]
Ph.D. title
Structural and chemical study of lignin and its recovery as Alfa macromonomer and/or activated charcoal precurseur
Supervision
Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Sami BOUFI, Professor, University of Sfax, Tunisia ♦♦ Gérard MORTHA, Professor, Grenoble INP-Pagora / LGP2
Abstract
Lignin precipitated from black soda cooking liquor of alfa (Stipa tenacissima) was carefully characterized and valorized following two different approaches: its utilization after chemical modification in view of preparing rigid polyurethane foams and its simple pyrolysis, in order to prepare charcoal. In fact, a comparative study concerning the careful characterization of the hydroxyl functions was realized using several methods and techniques, among which: the conductometric titration differential UV and 13C-NMR spectroscopy.
In the first approach, the precipitated lignin was converted in liquid polyols thanks to a chain-extension reaction with propylene oxide. These formulations were optimized by inspecting the effect of different parameters: lignin/propylene oxide ratio, amount of catalyst, molecular weight of the prepared polyols, hydroxyl index and glass transition temperature. The hydroxyl indexes and the viscosity of the prepared polyols were determined. The rigid polyurethane foams were studied in terms of their density, morphology and mechanical properties.
The lignin was then used as a precursor for the preparation of charcoal without any activation treatment and compared with a commercial homologue. The kinetic of the adsorption was performed and showed that the adsorption equilibrium was reached at about 50 min, and followed a pseudo-first order kinetic model. The adsorption isotherms revealed that lignin-based charcoal retained efficiently metal ions and presented a maximum adsorption capacity varying from 200 to 400 µmol/g. This was true even for concentrations much lower than 20 ppm. The saturated lignin-based charcoal was efficiently regenerated by washing with solutions of EDTA and nitric acid.
These two approaches for the valorization of precipitated lignin from black liquor of alfa cooking gave materials with promising properties. Most cases, materials with properties similar to conventional ones were obtained, which presents a viable option of rational valorization of this industrial abundant and renewable by-product.
Other members of the jury
Souhir ABID, Professor, University of Sfax, Tunisia ♦♦ Étienne FLEURY, Professor, INSA Lyon ♦♦ Latifa BERGAOUI, Professor, INSAT, Tunisia ♦♦ Limam EL ALOUI, Professor, University of Gafsa, Tunisia

Fedia Bettaieb EP KHIARI

September 26, 2015 - Fluid Mechanics, Energy, Processes [Thesis online]
Ph.D. title
Valuation of Tunisian cellulose waste.
Supervision
Alain DUFRESNE, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Farouk MHENNI, Professor, University of Monastir, Tunisia
Abstract
Many cellulosic sources are available in Tunisia in large quantities such as agricultural waste (vine stems) and marine residues (Posidonia oceanica leaves and balls). Their valorization presents an interesting activity to produce new products and bio-based biomass materials. The present work deals with the preparation, characterization and application of nanocellulose. In fact, different qualities of nanocellulose, namely cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF) were produced and characterized by various methods.
The objective was to better understand the structure and morphology of the nanofibers obtained from both plants. Finally, various nanocomposites were prepared using the cellulose nanocrystals and cellulose nanofibrils as reinforcing element in polyacrylate polymer as matrix. The obtained results were compared with those reported for other sources such as annual plants and wood. It has been shown that nanocellulose from Posidonia oceanica and vine stem can be used as a new alternative nanoreinforcing source in nanocomposite applications.
Other members of the jury
Mustapha MAJDOUB, Professor, University of Monastir, Tunisia ♦♦ Étienne FLEURY, Professor, INSA Lyon, France ♦♦ Samir BOUFI, Professor, University of Sfax, Tunisia

Thibaut MARTINI

March 31, 2015 - Fluid Mechanics, Energy, Processes [Thesis online]
Ph.D. title
Study of the ink formulation based on Cu, Zn, Sn S precursors and of the crystallization's annealing  for the non-vacuum deposit of photovoltaic layers
Supervision
Anne BLAYO, Lecturer-researcher, Grenoble INP-Pagora / LGP2 ♦♦ Céline MARTIN, Associate Professor, Grenoble INP-Pagora / LGP2 ♦♦ Konstantin TARASOV, Researcher, CEA Grenoble
Abstract
Kesterite (CZTS) is a semi-conductor only made of abundant elements. Its direct bangap between 1.0 and 1.5 eV makes it excellent candidate to replace the currently used absorbers in modules photovoltaic in thin coats.
This thesis describes the fabrication of thin films of CZTS by nanoparticles printing followed by crystallization annealing. Different hydrothermal synthesis of nanoparticles have been developed, some in continuous flow reactor, for a development on a larger scale. The influence of the types of precursors and synthesis conditions on the particles chemical composition was studied and their purity was evaluated.
The behavior of the colloidal dispersion is then characterized and three surface functionalizations based on dodecanethiol, dodecyl pyrrolidone and anions sulphides are presented. These stabilizations allow to make an ink-jet and spray ink adapted to the deposit on molybdenum. The printed and dried layers are then annealed in sulfur atmosphere. Annealing of at least 120 minutes is required. However, the growth of the layers is heterogeneous when printed with the nanoparticles stabilized by dodecanethiol and dodecyl pyrrolidone. The presence of carbon in layers, recognizable by spectroscopy Raman, inhibits the growth of the material. Only the thin layers printed by using purified and stabilized by anions sulphides nanoparticles allow the homogeneous growth of the material during annealing.
Other members of the jury
Stéphane DANIELE, Professor, IRCELYON, Lyon ♦♦ John KESSLER, Professor, Institut des Matériaux Jean Rouxel, Nantes ♦♦ Anne DAVIDSON,  Associate Professor, Laboratoire de Réactivité de Surface UPMC, Paris ♦♦ Anne KAMINSKY, Professor, IMEP-LAHC, Grenoble ♦♦ Georges BRÉMOND, Professor, INSA Lyon ♦♦ Alain RICAUD, CEO, Screen Solar

Date of update May 18, 2018

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