WorldCat Identities

Laboratoire de génie des procédés papetiers (Grenoble)

Overview
Works: 103 works in 111 publications in 2 languages and 183 library holdings
Roles: Other, Editor
Publication Timeline
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Most widely held works by Laboratoire de génie des procédés papetiers (Grenoble)
Modélisation du mécanisme de raffinage des pâtes à papier et étude de nouveaux paramètres géométriques liés aux plaques by Christine Rousselle-Manuel( )

2 editions published in 1989 in French and held by 3 WorldCat member libraries worldwide

ON A CHERCHE A MODELISER CERTAINS ASPECTS DU RAFFINAGE DES PATES AFIN D'EXPLIQUER ET DE LIMITER L'ENERGIE DEPENSEE. L'EXAMEN BIBLIOGRAPHIQUE SOULIGNE LA COMPLEXITE DES PHENOMENES, MIS EN JEU. UNE MODELISATION DE L'EFFET DES LAMES SUR LA PATE CONSISTE EN L'APPLICATION DE CONTRAINTES PULSEES D'ETIREMENT SUR UNE FIBRE INDIVIDUELLE. ON OBSERVE SA RIGIDIFICATION LORS DE L'ESSAI. LES FIBRES KRAFT ONT UN COMPORTEMENT PLUS VISQUEUX QUE LES FIBRES AU BISULFITE, D'OU UNE PLUS GRANDE DEPENSE ENERGETIQUE. DES OBSERVATIONS MICROSCOPIQUES REVELENT UNE AMELIORATION DE L'ETAT DE LA FIBRE. L'ETUDE DES PARAMETRES GEOMETRIQUES LIES AUX PLAQUES PERMET D'EVALUER LA FREQUENCE DES CONTRAINTES IMPOSEES AUX FIBRES. ON CALCULE UN NOMBRE DE POINTS DE CROISEMENT, UN ANGLE CARACTERISTIQUE ET UNE ENERGIE PAR IMPACT. ON ETABLIT UNE CORRELATION ENTRE LONGUEUR DES FIBRES ET RAPPORT NOMBRE DE POINTS DE CROISEMENT/ANGLE CARACTERISTIQUE. ON TRACE DES DIAGRAMMES D'OPTIMISATION ENERGETIQUE AFIN DE CHOISIR LA MEILLEURE GEOMETRIE DE PLAQUE
Procédés de séparation membranaire pour la production en continu de nanocristaux de polysaccharides : approche expérimentale et modélisation by Ahlem Romdhane( )

2 editions published in 2014 in French and held by 3 WorldCat member libraries worldwide

The current work investigates the use of cross flow microfiltration using ceramic membrane to fractionate the heterogeneous suspension obtained after starch hydrolysis in order to isolate starch nanocrystals. The final aim is to evaluate the possibility of coupling the filtration step to the hydrolysis step in a single production loop in order to enhance the starch nanocrystal production yield. The characterizations of the suspension (particle size and charge) obtained with the classic production process indicates that it was a mixture of starch nanocrystal aggregates and starch residues, individualized starch nanocrystals represent only 5 % of the initial starch. The fractionation study was done using two pilot plans, in a dead end configuration at laboratory scale (plate membrane) and in a cross flow configuration at semi-industrial scale (tubular membrane). Design of experiments methodology was used to optimize the fractionation efficiency when filtering a neutral suspension considering the effect of filtration parameter on the transmission yield and membrane fouling. In the optimized condition, it was possible to recover 25 % of starch nanocrystals while keeping the permeate flux at its highest value. Mean diameter of the recovered particle was less than 300 nm. At this condition, it was also possible to recover the starch nanocrystals directly from the acidic mixture obtained at the end of the hydrolysis step. The analysis of fouling mechanism using dead end filtration experiments highlights that membrane fouling occurs because a cake bult up at the membrane surface. This study investigates also the use of ceramic ultrafiltration membrane in a diafiltration process in order to purify the acidic suspension from soluble molecules without modifying particle size distribution which is a promising technique for a large scale production
Conception d'étiquettes autoadhésives par microencapsulation d'adhésif by Robin Abderrahmen( )

2 editions published in 2012 in French and held by 3 WorldCat member libraries worldwide

The main objective of this investigation is to prepare innovative silicone liner-free labels. It can be achieved by the adhesive 'self protection', thanks to its incorporation into microcapsules. This allows the preparation of 'dry labels' gluing under the application of a pressure, which induces the rupture of the microcapsules, thus releasing the core material, a pressure sensitive adhesive. The first step was to analyse 3 water-based PSA in view of their encapsulation. Then, the most suitable adhesive was microencapsulated by coacervation (using biopolymer as shell) and by in situ polymerisation. Two other encapsulation processes (spray-cooling and spray-drying), were also carried out at the LAGEP and were compared with the 2 former processes. Coating colour formulations were prepared with spray-cooling microcapsules (the most adhesive ones). Coating trials were carried out with a Meyer rod, and by screen printing. Compatibility between microcapsules and the label making process, using a flexographic printing press, was determined. Finally, the mains characteristics of the prepared innovative products (adhesion, application pressure) were compared to industrial self-adhesive homologues, and found that they could be suitable for the preparation of silicon liner-free envelops and stamps
Modélisation et simulation de l'atelier de régénération de l'usine Kraft by Jean-Baptiste Picot( )

2 editions published in 2012 in French and held by 3 WorldCat member libraries worldwide

L'atelier de régénération d'une usine kraft permet d'extraire des liqueurs noires les élémentschimiques nécessaires à la cuisson du bois et de les régénérer sous leur forme active, ainsi quede valoriser la fraction organique dissoute sous forme de chaleur. Les opérations unitaires enoeuvre sont nombreuses, complexes, et souvent mal décrites. Ce travail vise à permettre unemeilleure compréhension de la régénération, par la réalisation de modèles fiables décrivant lesphénomènes et processus dans chaque opération unitaire, leur implémentation algorithmiqueet leur exploitation par la simulation du procédé global
Étude de la rhéologie des suspensions fibreuses concentrées dans le but d'améliorer le recyclage des papiers by Benjamin Fabry( )

2 editions published in 1999 in French and held by 3 WorldCat member libraries worldwide

LES TRAVAUX RETRANSCRITS DANS CE MEMOIRE ONT POUR OBJECTIF DE QUANTIFIER LA PART DE L'ACTION MECANIQUE LORS DU PROCEDE DE REMISE EN SUSPENSION DES PAPIERS RECUPERES. UNE CARACTERISATION RHEOLOGIQUE A L'AIDE D'UNE APPROCHE ADIMENSIONNELLE EST PROPOSEE. NOUS AVONS ALORS INTRODUIT, PAR ANALOGIE MATHEMATIQUE, LE FACTEUR DE CISAILLEMENT (GENERALISATION DE LA VISCOSITE). CETTE APPROCHE, APPLIQUEE A DES PATES VIERGES ET RECYCLEES, A MIS EN AVANT LE ROLE PREPONDERANT DE LA CONCENTRATION MASSIQUE C M SUR (LA TEMPERATURE, L'INTRODUCTION DE SOUDE, ETC ONT UNE INFLUENCE MOINDRE). PAR AILLEURS, NOUS AVONS MONTRE QU'UNE ETUDE CINETIQUE SYSTEMATIQUE DU COMPORTEMENT DE L'ENCRE (FRAGMENTATION, DECROCHAGE, REDEPOSITION) EST NECESSAIRE AFIN DE MIEUX APPREHENDER L'INFLUENCE DES DIFFERENTS PARAMETRES DE REMISE EN SUSPENSION. MUNIS DE CETTE APPROCHE SYSTEMATIQUE, NOUS AVONS PU ABORDER DE FACON RATIONNELLE LA REMISE EN SUSPENSION. DANS UN PREMIER TEMPS, L'ETUDE EFFECTUEE AVEC LE MELANGEUR A MOUVEMENT PLANETAIRE (C M ENTRE 8 ET 20%) SANS AJOUT DE PRODUIT CHIMIQUE PERMET DE MONTRER QUE L'ENERGIE CONSOMMEE CARACTERISE LA QUALITE DE LA PATE APRES LE PULPEUR MAIS AUSSI APRES LA FLOTTATION (OBTENTION DE COURBES MAITRESSES). CETTE ENERGIE S'EXPRIME EN FONCTION DE ET DE L'AIRE DE CISAILLEMENT INDUITE PAR LE MOBILE D'AGITATION. DANS UN DEUXIEME TEMPS, L'ETUDE AVEC LE PULPEUR HELICO DE LABORATOIRE A MONTRE QUE LES ACTIONS THERMIQUE ET CHIMIQUE GOUVERNENT LA DISTRIBUTION DES PARTICULES LES PLUS GROSSES ALORS QUE L'ACTION MECANIQUE FRAGMENTE CES GROSSES PARTICULES EN PARTICULES PLUS PETITES. PAR AILLEURS, LES CINETIQUES DE DEFIBRAGE ET DE FRAGMENTATION SE SONT AVEREES D'AUTANT PLUS RAPIDES QUE EST ELEVE ET NOUS AVONS MONTRE QUE GLOBALISE LES DIFFERENTES CONDITIONS AU PULPEUR. POUR CHAQUE ETUDE, DES RECOMMANDATIONS SONT PROPOSEES DANS LE BUT D'OPTIMISER LA REMISE EN SUSPENSION (ASPECT ENERGETIQUE, QUALITE DE LA PATE, CONSEQUENCE AU NIVEAU DE L'ELIMINATION DES PARTICULES D'ENCRE)
Elaboration de matelas à base de fibres de verre par voie humide by Flavien Lozano( )

1 edition published in 2019 in French and held by 2 WorldCat member libraries worldwide

Les matelas fibreux à base de fibres de verre produits par voie humide ont des applications industrielles en tant que séparateur de batterie et matériaux d'isolation (cœur de panneaux d'isolation sous vide). Ces matériaux utilisent principalement des fibres submicroniques, relativement chères et pouvant présenter des risques pour la santé. Ce projet est une contribution à l'élaboration d'un procédé de fabrication par voie humide de matelas de fibres de verre visant à valoriser des fibres plus grossières, le produit final devant respecter un cahier des charges précis. Nous avons été amenés à étudier le comportement des fibres de verre dans les différentes étapes du procédé et à caractériser les matelas résultants. Nous nous sommes intéressés en particulier au comportement physico-chimique des suspensions aqueuses de fibres de verre. Nous avons caractérisé les propriétés de contexture, la résistance mécanique en traction, la compressibilité et la conductivité thermique des matelas fibreux. Les travaux expérimentaux nous ont permis de proposer une formulation de la composition optimisée et des conditions opératoires du procédé afin que le matelas final soit conforme au cahier des charges. Cette nouvelle composition intègre des fibres de renfort en faible quantité. Elle permet d'améliorer les caractéristiques mécaniques sans affecter les autres propriétés.Enfin, nous avons quantifié les coûts de production et les avons comparés à ceux du procédé actuellement utilisé avec des fibres grossières (production par voie sèche).Mots-clés : Génie papetier, physico-chimie, milieu poreux, fibres de verre, caractérisation
Production de bioéthanol à partir de biomasse lignocellulosique en utilisant des enzymes cellulolytiques immobilisées by Karthik Periyasamy( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Étude de la flottation réactive à l'ozone en vue de la valorisation des fibres cellulosiques de récupération et des rejets du recyclage by Filipe Olivier de Almeida dos Santos( Book )

2 editions published in 2009 in French and held by 2 WorldCat member libraries worldwide

This work studied the effect of ozone used as a reactive gas in flotation in order to optimise recovered cellulosic fibre deinking for the production of high brightness paper : improvement of the recycled fibre optical properties and reduction of the flotation rejects. A flotation pilot, coupled with an ozone generator, was developed and validated in the conventional air flotation operating conditions. The effect of ozone on the deinking process was studied for two recovered paper furnishes (offset prints and a mixture of 50/50 newsprints and magazines). The introduction of ozone led to the increase of ink removal, to a slight reduction of the deinking sludge production and to the partial degradation of the optical brighteners which improves the food-contact ability of deinking pulps. Moreover, the COD of the effluents is reduced by more than 25 %. These results showed that the ozone reactive flotation is a promising solution to improve the deinking efficiency and to decrease the pollution of its rejects
Etude de la métallisation de la face avant des cellules photovoltaïques en silicium by Sébastien Thibert( )

1 edition published in 2014 in French and held by 2 WorldCat member libraries worldwide

À l'échelle industrielle, la métallisation de la face avant des cellules photovoltaïques est réalisée grâce au procédé de sérigraphie depuis plus de 40 ans. Une pâte à base d'argent est imprimée avant d'être recuite à haute température. La robustesse, la simplicité et la haute cadence de production de ce procédé ont largement contribué à son succès. L'étape de métallisation est critique dans la chaîne de fabrication des cellules. D'un côté, les propriétés des contacts déposés déterminent les performances finales des cellules. D'un autre côté, plus de 7% de la consommation mondiale d'argent sont déjà destinés à l'industrie photovoltaïque. Avec les prévisions de croissance exponentielle de ce secteur, la quantité d'argent déposée lors de cette étape devient de plus en plus cruciale car elle régit le coût final des cellules. Elle dépend également de la qualité des contacts imprimés. Il est donc important d'optimiser le procédé de sérigraphie pour limiter la masse d'argent imprimée et maximiser le rendement des cellules. Les travaux présentés dans la première partie de cette thèse sont focalisés sur ces deux aspects. Dans un premier temps, le comportement rhéologique des pâtes de sérigraphie est étudié. Par la suite, une étude multifactorielle combinée à des simulations des pertes de puissance permet d'évaluer l'influence des paramètres de la sérigraphie sur le rendement des cellules et la masse d'argent déposée. Ces travaux ont conduit à la fabrication de cellules caractérisées par un rendement moyen de 19,0% à l'échelle industrielle. Le procédé de sérigraphie reste couteux et de nombreuses solutions alternatives sont à l'étude. En effet, la microstructure hétérogène des contacts cause des pertes électriques non négligeables en comparaison des cellules à haut rendement. Par ailleurs, la résolution limitée de ce procédé ne permet plus de réduire les dimensions des impressions, ce qui a un impact direct sur les pertes optiques et la masse d'argent déposée. Enfin, l'optimisation simultanée des propriétés électriques et géométriques des contacts complexifie son contrôle à l'échelle industrielle. Le concept double couche est une alternative innovante qui permet de s'affranchir de ces limitations. Une première couche est d'abord imprimée pour limiter la largeur initiale des contacts et améliorer l'interface avec la cellule. Une seconde couche de métal pur, déposée par voie électrolytique, vient épaissir cette dernière pour optimiser la hauteur et la conductivité de la grille de métallique. Dans le même temps, cette étape permet de contrôler précisément la masse d'argent déposée. Plusieurs solutions sont disponibles pour réaliser l'impression de la première couche. Grâce à sa flexibilité et à sa très haute cadence de production, le procédé de flexographie semble répondre au cahier des charges d'un tel dépôt dans des conditions industrielles. La seconde partie des travaux exposés dans cette thèse traite du développement de cette technique d'impression. Tout d'abord, le comportement rhéologique de plusieurs encres dérivées d'une pâte de sérigraphie classique est étudié. Dans un second temps, le procédé de flexographie est adapté au dépôt de lignes pouvant être épaissies par voie électrolytique (procédé LIP). Le potentiel de ce procédé est ensuite évalué à l'aide de modélisations du rendement et de la masse d'argent déposée. Finalement, la faisabilité du concept est démontrée grâce à la fabrication d'une cellule caractérisée par un rendement prometteur de 17,9%
Etude de la formulation d'encre à base de précurseurs Cu, Zn, Sn, S et du recuit de cristallisation pour le dépot hors vide de couches photovoltaïques by Thibaut Martini( )

1 edition published in 2015 in French and held by 2 WorldCat member libraries worldwide

Les kësterites, ou Cu2ZnSn(S,Se)4 (CZTS), sont des matériaux semi-conducteurs composés uniquement d'éléments abondants. Leur gap direct compris entre 1.0 et 1.5 eV en fait d'excellents candidats pour remplacer les absorbeurs actuellement utilisés en couches minces. Ce travail de thèse décrit la fabrication de couches minces de Cu2ZnSnS4 par impression de nanoparticules suivie d'un recuit de cristallisation. Différentes synthèses hydrothermales de nanoparticules ont été développées, dont certaines en réacteur à flot continu, en vue d'un développement à plus grande échelle. L'influence des types de précurseurs et des conditions de synthèse sur la composition chimique des particules est étudiée ainsi que leur pureté est évaluée. Le comportement en dispersion colloïdale est ensuite caractérisé et trois fonctionnalisations de surfaces à base de dodecanthiol, dodecyl pyrrolidone et anions sulfures sont présentées. Ces stabilisations permettent la fabrication d'encre jet d'encre et spray adaptées au dépôt sur molybdène. Les couches imprimées et séchées sont recuites sous atmosphère de soufre. Des recuits d'au moins 120 minutes sont nécessaires. Cependant la croissance des couches est hétérogène lorsque celles-ci sont imprimées avec les nanoparticules stabilisées par le dodecanethiol et le dodecyl pyrrolidone. La présence de carbone dans les couches, identifiable par spectroscopie Raman, inhibe la croissance du matériau. Seules les couches minces imprimées à l'aide de nanoparticules purifiées et stabilisées par anions sulfures permettent la croissance homogène du matériau lors du recuit
Conception et réalisation d'un pilote pour le traitement photocatalytique d'effluents gazeux pollués en composés organiques volatils : application à l'élimination du méthanol dans l'air by Christine Nguyen Dinh An( Book )

2 editions published in 2001 in French and held by 2 WorldCat member libraries worldwide

Après une description du processus photocatalytique et sa comparaison avec les traitements actuels de COV, le cahier des charges d'un pilote de traitement photocatalytique des effluents gazeux est établi. Un photoréacteur, dans lequel le dioxyde de titane (photocatalyseur) est supporté sur un filtre de fibres de verre, est alors conçu et intégré dans un pilote. Les paramètres d'entrée sont validés et le photoréacteur modélisé selon un réacteur idéal. Le méthanol est pris comme COV cible pour prouver que l'unique phénomène de disparition du COV est la photocatalyse. Dans le domaine de limitation cinétique, la vitesse de disparition du COV est alors modélisée selon la théorie de Langmuir-Hinshelwood. La modélisation met en évidence l'influence de la concentration en COV, de l'humidité relative et de l'intensité UV. La simulation d'un traitement d'émission fugitive permet alors une première évaluation de l'efficacité du pilote. Des suggestions d'amélioration du photoréacteur sont enfin proposées
Polyamidoamine epichlorohydrin-based papers : mechanisms of wet strength development and paper repulping by Eder José Siqueira( )

1 edition published in 2012 in English and held by 2 WorldCat member libraries worldwide

Polyamideamine epichlorohydrin (PAE) resin is a water soluble additive and the most used permanent wet strength additive in alkaline conditions for preparing wet strengthened papers. In this thesis, we studied some properties of PAE resins and wet strengthened papers prepared from them. In order to elucidate PAE structure, liquid state, 1H and 13C NMR was performed and permitted signals assignment of PAE structure. PAE films were prepared to study cross-linking reactions and then thermal and ageing treatments were performed. According to our results, the main PAE cross-linking reaction occurs by a nucleophilic attack of N atoms in the PAE and/or polyamideamine structures forming 2-propanol bridges between PAE macromolecules. A secondary contribution of ester linkages to the PAE cross-linking was also observed. However, this reaction, which is thermally induced, only occurs under anhydrous conditions. The mechanism related to wet strength development of PAE-based papers was studied by using CMC as a model compound for cellulosic fibres and PAE-CMC interactions as a model for PAE-fibres interactions. Based on results from NMR and FTIR, we clearly showed that PAE react with CMC that is when carboxylic groups are present in great amounts. Consequently, as the number of carboxylic groups present in lignocellulosic fibres is considerably less important and the resulting formed ester bonds are hydrolysable, we postulate that ester bond formation has a negligible impact on the wet strength of PAE-based papers. In the second part of this work, a 100% Eucalyptus pulp suspension was used to prepare PAE-based papers. PAE was added at different dosages (0.4, 0.6 and 1%) into the pulp suspension and its adsorption was indirectly followed by measuring the zeta potential. Results indicate that the adsorption, reconformation and/or penetration phenomena reach an apparent equilibrium between 10 and 30 min. Moreover, we showed that the paper dry strength was not significantly affected by the conductivity level (from 100 to 3000 µS/cm) of the pulp suspension. However, the conductivity has an impact on the wet strength and this effect seems to be enhanced for the highest PAE dosage (1%). We also demonstrated that storing the treated paper under controlled conditions or boosting the PAE cross-linking with a thermal post-treatment does not necessarily lead to the same wet strength. Degrading studies of cross-linked PAE films showed that PAE degradation in a persulfate solution at alkaline medium was more effective. A preliminary study of industrial PAE-based papers (coated and uncoated papers) was also performed. For uncoated paper, persulfate treatment was the most efficient. For coated papers, all treatments were inefficient in the used conditions, although a decrease of the wet tensile force of degraded samples was observed. The main responsible of the decrease of persulfate efficiency for coated papers was probably related to side reactions of free radicals with the coating constituents
Conception, mise en oeuvre et caractérisation de nouveaux bio-nano-matériaux fonctionnels. by Nathalie Lavoine( )

1 edition published in 2013 in French and held by 2 WorldCat member libraries worldwide

New functional materials, called active materials, are developing with different processes and for several applications. The target is to give new functions like virus detection, active substance release, end of life control...This topic is more and more important in our society and industry. Researches are still rare and more scientific expertise is expected. Meanwhile, use of biobased materials interests more and more scientists. Among biomaterials, the use of bionanoparticles is strongly increasing and high value added applications are targeted. However, their use in release control of active substances has not yet been studied in detail in spite of promising results on barrier properties improvement. Their very high specific area could also be considered as a advantege concerning their use as active material carrier. In packaging field, active materials are materials which change condition of packed product to increase its shelf life by keeping quality and safety. Three main types of active packaging are existing : scavenger systems (02, humidity), anti-microbial systems, barrier systems. Some research studies have just been launched about the two first categories of active packaging with some promising results. The target is then to understand and develop innovative functional bionanomaterials by considering : sustainability and safety. Three topic will be studied in detail : - Biomaterials : cellulose fibers, bionanoparticules (NFC, Wh, SNP), active biomolecules - Process : grafting, encapsulation chitosane, coating, extrusion, ink jet - Properties : 02 scavenger, anti-microbial system, food contact A better understanding of migration and the end-use properties characterization will be main point of the scientific research during the project. Different strategies will be tested and optimisation of best solution will follow by finishing with an up-scaling study
Etudes multi-échelles des couplages entre les propriétés hygroélastiques des papiers et leur microstructure by Cyril Marulier( )

1 edition published in 2013 in French and held by 2 WorldCat member libraries worldwide

The objective of this work is to study the coupling between the hygroelastic properties ofpapers and their microstructure. The use of images of models acquired by X-ray microtomographypapers allowed the characterization in an unprecedentedmanner of the evolutionofmicrostructural properties of thesematerials according to their production conditions andduring tests where they were placed in atmosphere at controlled relative humidity. These resultsprovide a new contribution to the knowledge of the statistical nature of the descriptorsof fibre properties (size and orientation) and their contacts (surface, bonding degree ratio), ofthe architecture of fibrous networks that papers constitute (number of fibre-to-fibre bonds)as well as of the size of the representative elementary volumes of microstructural and elasticproperties. Based on this information, various models, more or less sophisticated, were developedin the framework of the theory of homogenisation of discrete periodic structures todescribe the mechanical properties of paper. This approach sheds new light on the role offibre-to-fibre bonds on themechanical behaviour of thesematerials
Etude de l'activation du peroxyde d'hydrogène par le complexe cuivre(II)-phénanthroline pour la décoloration de fibres cellulosiques récupérées by Elsa Walger( )

1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide

Today, recovered papers are reused for the manufacture of bright paper after deinking and fiber bleaching, which generally starts with an alkaline hydrogen peroxide stage (H2O2). However, the efficiency of H2O2 is often limited due to its low reactivity on the azo groups of paper dyes contained in recovered papers. The goal of this study was to improve the removal of these azo dyes by H2O2.The improvement of H2O2 bleaching has been studied thoroughly in the context of chemical pulp delignification. In particular, the activation or catalysis of H2O2 by copper(II)-phenanthroline complexes (Cu-Phen) was found to be very effective. This inspired a preliminary bleaching study on deinked pulp and dyed pulp, and resulted in significant improvement of dye removal, which gave birth to our project.The purpose of this work was to determine to what extent copper(II)-phenanthroline could improve the hydrogen peroxide color-stripping of dyed cellulosic fibers, and how. To answer this question, three intermediate issues were addressed: (1) does Cu-Phen alone have an effect on the dye? (2) does Cu-Phen improve the color-stripping of a dyed pulp by H2O2? (3) how does the H2O2/Cu-Phen system enhance the dye-color-stripping efficiency?This work was thus divided into three studies: (1) the selected dyes and the complex were characterized in the absence of any oxidant and the interactions between the two were examined, (2) the H2O2/Cu-Phen system was applied on two dyed pulps to assess their color-stripping potential and to attempt to optimize it, and (3) the oxidation mechanism was investigated via trials in aqueous solution, with and without cellulose.Using several analytical techniques (NMR, FTIR, UV-vis and EPR spectroscopy; ESI-MS) and speciation calculations, this work proved that the Cu-Phen complex enhanced H2O2 for the color-stripping of azo dyes, with and without fibers. It also provided evidence that phenanthroline acted as a stabilizer to adjust the solubility, stability and redox potential of copper(II), but may not be indispensable. The substrate (dyes but also cellulose) was strongly degraded by the H2O2/Cu-Phen system. The results of the mechanistic study supported the hypothesis of substrate oxidation by radicals produced via decomposition of H2O2 rather than by hydrogen peroxide itself. This mechanism, strongly dependent on the pH, is probably part of a catalytic cycle.Finally, along with further research proposed based on our conclusions, this thesis should contribute to the improvement of deinked pulp bleaching as well as wastewater treatment in the pulp and textile industries
Nanocomposites et mousses à base de nanofibrilles de cellulose : rhéologie au cours de leur mise en forme et propriétés mécaniques by Florian Martoïa( )

1 edition published in 2015 in French and held by 2 WorldCat member libraries worldwide

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 experi-mental, 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 obtai-ned. We show that the flow of NFC suspensions is highly heterogeneous and exhibits com-plex 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 hydrody-namic 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 (i) that NFCs form highly connected nanofibrous structures with in-plane random orientation, (ii) that these connected NFC networks play a leading role on the mechanical behaviour of the nanocompo-sites and (iii) 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 microto-mography), 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
Fonctionnalisation de nanofibrilles de cellulose pour le développement de dispositifs médicaux biosourcés by Hippolyte Durand( )

1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide

In line with the ever-increasing academic and industrial interest for wood derived nanocellulose, the present work investigated the chemical surface modification of cellulose nanofibrils (CNFs) for biomedical application. Drugs and pro-drugs of active principle ingredients (APIs) were covalently immobilized or adsorbed onto CNFs films or suspensions. For covalent immobilization, the first strategy selected calls for water-based and single step esterification of CNF films. The resulting materials demonstrated antibacterial activity against both gram-positive and gram-negative bacterial strains, with a prolonged contact-active effect. In the second strategy, CNFs suspensions were modified through a multistep reaction, involving amidation and click chemistry, still water-based. Highly innovative characterization tools, such as dynamic nuclear polarization (DNP) enhanced nuclear magnetic resonance (NMR), complemented well-established techniques to confirm the success of grafting. In parallel to covalent immobilization, an adsorption strategy was also adopted, on both CNFs films and suspensions. Then, the CNF films with grafted or adsorbed APIs were used for preparing 100% CNF medical devices for topical applications. Another component of this work used CNF suspensions with grafted or adsorbed APIs were embedded in collagen matrices to prepare model medical device of soft tissue repair implants. Antibacterial activity against both aerobic and anaerobic bacteria, together with controlled release properties were assessed confirming that such composites present the expected active properties, and can be used for the design of innovative medical devices.Key words: nanocellulose, cellulose nanofibrils, functionalization, medical devices, antibacterial activity, drug release
Extraction de nanofibrilles de cellulose à structure et propriétés contrôlées : caractérisation, propriétés rhéologiques et application nanocomposites by Karima Ben Hamou( )

1 edition published in 2015 in French and held by 2 WorldCat member libraries worldwide

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
Elaboration of flexible lithium - ion electrodes by printing process by Oussama El Baradai( )

1 edition published in 2014 in English and held by 2 WorldCat member libraries worldwide

The work presented in this manuscript describes the manufacturing of lithium-ion batteries on papers substrates by printing technique. Its aim is the development of new up scalable and large area techniques as screen printing for the fabrication of lithium-ion batteries and the replacement of conventional toxic components by bio-sourced one and water based solvent. First results shows how it is possible to formulate cellulose based ink tailored for screen printing technology with suitable properties for lithium-ion batteries requirements. Electrodes were manufactured and tested from a physical and electrochemical point of view and two strategies were proposed to enhance performances. Finally, by considering results obtained for the electrodes, a full cell was manufactured with a new assembling strategy based on: front / reverse printing approach and the embedding of the current collectors during printing stage. As a final point cells were characterized and compared with others obtained by conventional assembling strategies
Etude de l'impact de l'extraction des hémicelluloses du bois sur les procédés d'obtention de cellulose et d'éthanol dans le cadre d'une bioraffinerie lignocellulosique by Lucie Boiron( )

1 edition published in 2012 in French and held by 2 WorldCat member libraries worldwide

Le renouveau des biocarburants pourrait être aussi celui de l'industrie chimique de la pâte àpapier, en diversifiant l'éventail des produits fabriqués à partir de bois. Cette étude porte surl'intégration d'une extraction des hémicelluloses du bois au procédé Kraft dans le cadre d'une coproductionde fibres cellulosiques et de bioéthanol.Le travail expérimental de cette étude balaie l'ensemble du procédé depuis l'extraction de plus dela moitié des hémicelluloses de bois de résineux, par autohydrolyse ou par hydrolyse à l'acidedilué, jusqu'à la production de fibres cellulosiques blanchies et d'éthanol obtenu par la fermentationdes hydrolysats.Les pâtes de bois préhydrolysé se sont distinguées par de très bonnes aptitudes à ladélignification lors de la cuisson Kraft et lors du blanchiment à l'oxygène. Une analyse desconstituants des pâtes de bois préhydrolysé a permis de comprendre pourquoi la préhydrolyseconduit à une diminution du rendement de cuisson (perte de lignine et de la totalité deshémicelluloses dont les xylanes). L'analyse des lignines de pâtes écrues de bois préhydrolysé apermis d'émettre une hypothèse quant à l'excellente aptitude de ces pâtes à la délignification lorsdu blanchiment à l'oxygène.En définitive, l'intégration d'une extraction des hémicelluloses à une usine Kraft telle qu'elle estproposée par cette étude permet d'obtenir à partir de 100 kg de bois de résineux, 27 à 36kilogrammes de fibres cellulosiques blanchies et jusqu'à 6 litres de bioéthanol. Ces fibrescellulosiques blanchies présentent des caractéristiques attrayantes pour la production de cellulose àusage chimique ou de nanocristaux de cellulose
 
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Alternative Names
Laboratory of pulp and paper Science and graphic arts (Grenoble)

LGP2

LGPP

UMR 5518

UMR5518

Unité Mixte de Recherche 5518

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French (22)

English (5)