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LGP2 - Ph.D. thesis defended in 2020


11 December 2020 - Materials, Mechanical, Civil Engineering, Electrochemistry
Ph.D. title
Preparation and characterization of bionanocomposites based on protein and cellulose nanocrystals by continuous casting
Julien BRAS, Senior Lecturer HDR, Grenoble INP-Pagora / LGP2 ♦♦ Luiz Henrique CAPPARELLI MATTOSO, Senior Researcher , Embrapa / UFSCar
This Ph.D. thesis covers the production and characterization of gelatin/cellulose nanocrystals (CNC) films intended for functional food packaging.
The up-scalability of the gelatin/CNC films was attained by continuous casting. The continuous casting processing was proven to be advantageous when compared to the bench solution casting method. Tensile tests, thermogravimetric analysis and water vapor permeability analysis showed that the continuously cast gelatin/CNC films had exceptionally better performance than the films obtained by bench casting.
The suitability of CNC was successfully extended by functionalization of CNC with natural molecule like rosin and tannic acid to obtain successfully anti-microbial and anti-oxidant properties.
This thesis provides a comprehensive understanding of how nanocellulose can be explored to develop biodegradable films based on gelatin with enhanced properties or extra functionalities. A continuous solution casting was applied for scaling up the production of gelatin/CNC-based films making them highly desirable for packaging applications.


10 December 2020
Ph.D. title
Flax fibres modification by cellulose nanocrystals and xyloglucan for the development of hierarchical biobased composites
Jean-Charles BÉNÉZET, Professor, IMT Mines Alès ♦♦ Julien BRAS, Associate Professor HDR, Grenoble INP-Pagora / LGP2 ♦♦ Nicolas LE MOIGNE, Teacher-researcher, IMT Mines Alès ♦♦ Bernard CATHALA, Research Director, INRAe Nantes
This thesis project aims at developing flax fibres surface treatment for the improvement of the mechanical properties of biocomposites with polymeric matrix and flax reinforcements.
This surface modification is inspired by the hierarchical structures present in biological systems (bone, nacre or wood), composed of nano-objects which allow a better transfer of loads in these materials. This presence of nano-sized objects makes it possible to reach impressive strength and toughness values and to limit cracks propagation.
In this project, products derived from lingo-cellulosic biomass, namely cellulose nanocrystals (CNC) and xyloglucan (XG), were chosen for their interesting properties and mutual affinity to create hierarchical flax fibres. In a first step, the adsorption of XG and CNC on flax fibres was localized and quantified using fluorescent markers.  In addition, atomic force microscopy measurements of adhesive force revealed the creation of an extensible XG/CNC network on the fibre surface. Subsequently, two paths were proposed with the elaboration of thermoplastic (polypropylene/flax fibres) and thermoset (epoxy resin/flax fabric) biocomposites using these nanostructured fibres. In both cases, an increase of the work of rupture has been measured by micro- and/or uniaxial tensile tests, allowing dissipating more energy upon breakage.
All this work has allowed evaluating the potential of different hierarchical natural reinforcements (unidirectional fabric or short flax fibers) for the development of structural biocomposites with a focus on the fiber/matrix interphase zone.
Other members of the jury
Joël BRÉARD, Professor, Université de Caen Normandie ♦♦ Jannick DUCHET-RUMEAU, Professor, INSA Lyon ♦♦ Hélène ANGELLIER-COUSSY, Associate Professor, Université de Montpellier ♦♦ Tatiana BUDTOVA, Research Director, MINES ParisTech  ♦♦ Evelyne MAURET, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Laurent HEUX, Research Director, Cermav - CNRS, Grenoble


20 November 2020 - Materials, Mechanical, Civil Engineering, Electrochemistry [Online thesis]
Ph.D. title
Smart and Safe Packaging
Julien BRAS, Associate Professor HDR, Grenoble INP-Pagora / LGP2 ♦♦ David GETHIN, Professor, Swansea University, UK ♦♦ Aurore DENNEULIN, Associate Professor, Grenoble INP-Pagora / LGP2 ♦♦ Davide DEGANELLO, Professor, Swansea University, UK
In line with the latest innovations in the packaging field, this joint project aims at implementing new and innovative micro- and nanoparticles for the development of active and intelligent packaging solutions dedicated to food and medical packaging applications. More specifically, the project combines two major developments which both falls within the scope of active and intelligent packaging.
In this work, a specific focus was given to the development of an antibacterial packaging solution and to the development of smart gas sensors. The antibacterial strategy developed was based on the combination of two active materials - silver nanowires and cellulose nanofibrils - to prepare antibacterial surfaces. The formulation as an ink and the deposition processing has been deeply studied for different surface deposition processes that include coatings or screen-printing. Results showed surfaces that display strong antibacterial activity both against Gram-positive and Gram-negative bacteria, but also interesting properties for active packaging applications such as a highly retained transparency or enhanced barrier properties. Regarding the second strategy, gas sensors have been prepared using a combination of Copper benzene-1,3,5-tricarboxylate Metal Organic Framework and carbon-graphene materials, deposited on flexible screen-printed electrodes. The easy-to-produce and optimized sensors exhibit good performances toward ammonia and toward humidity sensing, proving the versatility and the great potential of such solution to be adapted for different target applications.
The results of this project lead to innovative solutions that can meet the challenges raised by the packaging industry.
Other members of the jury
Davide BENEVENTI, CNRS Research Director, Grenoble INP-Pagora / LGP2 ♦♦ Eliane ESPUCHE, Professor, Université Claude Bernard Lyon 1 ♦♦ Long LIN, Professor, University of Leeds, UK ♦♦ Kar Seng TENG, Professor, Swansea University, UK


1st October 2020 - Fluid Mechanics, Energy, Processes [Online thesis]
Ph.D. title
Ozone-reactive flotation: impacts on papermaking ability – processes, fibers and effluents – of lignocellulosic fibers suspensions.
Marc AUROUSSEAU, Professor, Grenoble INP-Pagora / LGP2  ♦♦ Nathalie MARLIN, Associate Professor HDR, Grenoble INP-Pagora / LGP2 ♦♦ Agnès BOYER, Associate Professor, Grenoble INP-Pagora / LGP2
The objective of this study is to increase the knowledge of the effect of ozone introduced as a reactive gas in the flotation process on the performance of printed papers deinking as well as on the paper properties of recycled cellulosic fibers (physical and optical properties, paper process-ability).
Trials with high ozone dosages (2.97 % based on the mass of fibers) were carried out in a pilot laboratory flotation cell (15 L). Several mixtures of recovered papers were studied:
  • a mixture of 50 % magazines and 50 % newspapers;
  • two wood-free recovered lignocellulosic fiber pulp models (mechanical pulp content lower than 15 %) to limit the yellowing effect of ozone on lignified fibers;
  • a wood-free industrial blend of 90 % office papers and 10 % magazines.
Tap water and a model process water were used to dilute the fibers before deinking. For a better understanding of the ozone reactivity, trials were also carried out on the two types of water, in the absence of fibers.
The main advantages of the reactive ozone flotation process are:
  • the strong reduction of the soluble COD in the effluent, up to 63% compared to air flotation in the case of trials with industrial papers, using model process water;
  • 1 point increase in fiber yield;
  • the conservation or improvement of the paper properties of recycled fibers.
Ozone reacts preferentially with soluble contaminants so that the fibers are not affected. This process is very suitable for the deinking of wood-free printed papers.
Other members of the jury
Véronique COMA, Associate Professor HDR, Université de Bordeaux ♦♦ Annabelle COUVERT, Professor, ENSCR, Rennes ♦♦ Pierre DUMONT, Professor, INSA Lyon ♦♦ Nicolas GONDREXON, Professor, LRP / Université Grenoble Alpes


3 July 2020 - Fluid Mechanics, Energy, Processes [Online thesis]
Ph.D. title
Process for the purification of cellulose from wood by coupling enzymatic and chemical reactions.
Christine CHIRAT, Professor, Grenoble INP-Pagora / LGP2  ♦♦ Dominique LACHENAL, Emeritus Professor, Grenoble INP-Pagora / LGP2
Nowadays, applying clean technologies is in the center of attention in different industries in order to decrease the release of pollutants in the environment. Maximizing the revenues of a production line by valorizing the value-added precious side products is also looked for. In the case of the cellulose industry, trying to valorize all the wood components instead of burning half of the wood content with the black liquor would improve the economy model of the mills and ensure their perennation in some cases. Kraft pulping is the dominant pulping method producing paper-grade pulps. Among various current and potential value-added products in pulp and paper industry, hemicelluloses are of the important ones, as they represent up to 30% of wood mass, and up to now they have not been valorized except for the production of energy. There are two ways under study by several research groups to have access to hemicelluloses when considering the kraft process, which is the dominant process in the cellulose industry: either they can be partially extracted by an autohydrolysis process prior to the kraft cooking, or they could be extracted from paper pulps which still contain from 15 to 30% of hemicelluloses.
In this study we will focus on the extraction of hemicelluloses from bleached paper pulp by using enzymes alone, or in combination with cold caustic extraction. Indeed, we aim at extracting rather pure hemicelluloses in their oligomeric form for a possible future usage as prebiotics for example. Acidic processes are thus excluded as acid hydrolysis is prone to depolymerize oligomers to monomers and to degrade sugar monomers into furans. Acidic process could also degrade cellulose. The advantage of using enzymes is that pure hemicelluloses should be obtained, as enzymes are selective. The choice of bleached pulps as raw material should ensure to have access to purer hemicelluloses than from an autohydrolysis process: indeed, bleached pulp do not contain lignin any more, and hemicelluloses in bleached pulps should be free of acetyl groups, and only few uronic acid groups should remain.
Xylanase and mannanase are the two enzymes that will be investigated. These enzymes have already been tested in the pulp and paper industry, as bleaching boosting agents. But still there are many challenges in applying hemicellulases to valorize hemicelluloses from kraft pulps, among them the limitation in the extraction of remained hemicelluloses is of critical ones, which is why we will also study a combination between enzymes and a CCE treatment. The study is divided into two parts: the first part will investigate the effect of the two enzymes on bleached softwood and hardwood pulps, in combination or not with CCE, and the second part will study the structure of the oligosaccharides extracted.
Other members of the jury


19 June 2020 - Fluid Mechanics, Energy, Processes
Ph.D. title
Understanding of the ageing phenomena occurring in electrotechnical papers in power transformers and research of industrial solutions.
Gérard MORTHA, Professor, Grenoble INP-Pagora / LGP2  ♦♦ Nathalie MARLIN, Associate Professor HDR, Grenoble INP-Pagora / LGP2  ♦♦ Lucie BOIRON, Research Engineer, Ahlstrom-Munksjö
Power transformers are expensive devices and the degradation of the cellulosic insulation paper contributes to limiting the transformer life expectancy. This work studies the kinetic degradation of two electrotechnical papers during accelerated ageing trials in mineral oil: one standard paper and one Thermally Upgraded paper (TU) containing an additive.
The degradation of the standard paper, measured via the cellulose viscometric degree of polymerisation (DPv), follows a first order kinetic model and the calculated activation energy is close to activation energy reported for the acid hydrolysis of cellulose in the literature. The TU paper behaves differently since the additive slows the paper degradation, and none of the tested kinetics models succeed to model experimental data. A deeper study of the additive reaction mechanism confirms and completes the hypotheses presented in the literature.
Moreover, some mechanical characterizations of aged papers highlight a correlation between the cellulose DPv and the double fold resistance of the paper. Thereafter, it has been discussed if the presence of lignin in paper presents a protective effect on cellulose and it has been shown that it leads to the production of methanol (used as a marker of paper degradation to monitor power transformers).
Finally, a new protective solution on the paper surface, gave encouraging results, particularly in terms of paper mechanical strength properties preservation.
Other members of the jury
Anne-Laurence DUPONT, CNRS Research Director, MNHN CRC, Paris ♦♦ Thierry PAILLAT, Professor, Université de Poitiers ♦♦ Nathalie BARNEL, Research Engineer, EDF ♦♦ Olivier LESAINT, CNRS Research Director, G2ELab, Grenoble


5 March 2020 - Materials, Mechanical, Civil Engineering, Electrochemistry
Ph.D. title
Surface modifications of cellulose nanocrystals for biobased food packaging applications.
Julien BRAS, Associate Professor HDR, Grenoble INP-Pagora / LGP2 ♦♦ Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Philippe ROGER, Professor, Université Paris-Saclay ♦♦ Hanène SALMI-MANI, Associate Professor, Université Paris-Saclay
The purpose of this project is to develop new surface chemical modifications of cellulose nanocrystals (CNCs), in order to enhance their compatibility with biobased poly(lactic acid) (PLA) polymer, and to combine their respective outstanding intrinsic properties. Biobased PLA-based multi-phase materials, including the designed nanostructures, are produced. Furthermore, the final materials are expected to be used in food packaging sector, and the improvement of the barrier properties of the PLA, especially towards oxygen and water vapour, is a key point in the characterization of the materials. In this project, different routes are proposed for the grafting of various compounds – polymers or single molecules – on the surface of the CNCs. Their grafting efficiency has been confirmed and carefully characterized. The modified CNCs are then introduced in PLA-based materials via two different strategies. Indeed, they are either used as nanofillers in a PLA matrix with inclusion rates comprised between 2 and 10 wt%, or as an inner layer of PLA-based multi-layered materials. In both cases, final PLA-based materials including various designed cellulosic nanomaterials exhibit enhanced and highly encouraging properties in terms of homogeneity, transparency, and barrier towards oxygen and water vapour, in accordance with required properties for food packaging materials.
Other members of the jury
Bénédicte LEPOITTEVIN, Associate Professor, ENSICAEN ♦♦ Jose-Maria LAGARON, Professor, CSIC, Espagne ♦♦ Hélène ANGELLIER-COUSSY, Associate Professor, Université de Montpellier ♦♦ Evelyne MAURET, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Sandra DOMENEK, Associate Professor, AgroParisTech

Esakkiammal Sudha ESAKKIMUTHU

30 January 2020 - Materials, Mechanical, Civil Engineering, Electrochemistry [Online thesis]
Ph.D. title
Study of new chemical derivatization techniques for lignin size exclusion chromatography characterization.
Gérard MORTHA, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Nathalie MARLIN, Associate Professor HDR, Grenoble INP-Pagora / LGP2
Lignin is the second most abundant biopolymer on earth after cellulose and it consists of highly-branched, three dimensional aromatic structures with variety of functional groups.
This research work was to establish lignin derivatization methods for lignin analysis, to quantify functional groups and to determine lignin molar mass distribution (MMD) by size exclusion chromatography. Five technical lignin samples are considered: Protobind 1000, Organosolv, Pine Kraft, Eucalyptus Kraft and Indulin. They are derivatized through classical acetylation method and new methods such as fluorobenzylation and fluorobenzoylation. The number of hydroxyl present in the lignin samples are quantified through GC and NMR (1H, 13C, 19F and 31P) techniques. The molar mass distribution of derivatized lignin samples are calculated using different SEC columns with different solvents (DMAc and THF). Conventional and universal calibration methods are used for MMD calculations.
With this approach, new derivatization methods significantly enhance lignin solubility in THF and improve chromatographic results. Universal calibration leads to about three times higher molar mass values than by conventional calibration.
Other members of the jury
Nicolas BROSSE, Professor, Université de Lorraine ♦♦ Christophe GEANTET, CNRS Research Director, Université Lyon 1 ♦♦ Sami HALILA, CNRS Researcher, Université Grenoble Alpes ♦♦ Marie-Christine BROCHIER-SALON, Research Engineer, Grenoble INP ♦♦ Dominique LACHENAL, Emeritus Professor, Grenoble INP


8 january 2020 - Fluid Mechanics, Energy, Processes [Online thesis]
Ph.D. title
Development of fibrous cellulosic materials for the production of bio-based  3D printed objects by extrusion.
Didier CHAUSSY, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Aurore DENNEULIN, Associate Professor, Grenoble INP-Pagora / LGP2 ♦♦ Davide BENEVENTI, CNRS Research Director, Grenoble INP-Pagora / LGP2 ♦♦ Sabine ROLLAND DU ROSCOAT, Associate Professor, Université Grenoble Alpes / 3SR
First, this project has evaluated the compatibility of aqueous and high solid content formulations with AM by extrusion. Formulations composed of micrometric organics fillers (cellulose fibers or powder) and cellulose derivatives (carboxymethyl cellulose) were investigated and results in a selection of homogeneous pastes with strong potential for AM by extrusion and limited deformation of the printed part upon air drying.
The second stage of this project focused on adjustment and optimization of AM by extrusion equipment and the related settings to guarantee an optimum shape accuracy of 3D printed parts compared to the 3D numerical model. A printing setting guideline and design limitations adapted to the developed paste were suggested. To characterize the printing parts, different innovative methods such as the temporal monitoring by X-ray tomography of a printed part upon drying were implemented.
The results of this project lead to the AM by extrusion of complex part 100% cellulose based with mechanical properties close to thermoplastic materials commonly used with fused filament fabrication process.
Other members of the jury
Roberta BONGIOVANNI, Professor, Politecnico di Torino, Italy ♦♦ Pierre DUMONT, Professor, INSA Lyon ♦♦ Gilberto DE FREITAS SIQUEIRA, Researcher, Empa, Switzerland ♦♦ Laurent ORGÉAS, CNRS Research Director, Université Grenoble Alpes / 3SR

Date of update June 22, 2021

LGP2 Laboratoire Génie des Procédés Papetiers
Laboratory of Process Engineering for Biorefinery,
Bio-based Materials and Functional Printing

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