Développement de nouveaux matériaux d'emballage à base de micro- et nano-fibrilles de cellulose. Les micro- et nano-fibrilles de cellulose (MFC/NFC) sont des nanomatériaux issus de ressources renouvelables présentant un fort intérêt notamment pour le domaine de l'emballage. En plus des avantages naturels de la cellulose, ces matériaux offrent des propriétés barrières prometteuses (Oxygen, graisse), de bonnes propriétés de résistance mécanique ainsi que la possibilité de produire des films transparents. L'objectif de cette thèse était de développer par des procédés d'endution un carton barrière au gaz et aux graisses en utilisant les MFC/NFC. Différentes suspensions de MFC/NFC ont été premièrement characterisées puis utilisées pour la production de films afin de déterminer leurs propriétés intrinsèques. Des films modèles ont ensuite été développés avec la production de composites matrice/MFC. Une dernière partie était focalisée sur l'introduction de MFC/NFC dans des sauces de couchage afin de développer une couche barrière à la surface d'un carton. Un démonstrateur a ainsi été validé à l'échelle pilote. Le potentiel des MFC/NFC a été démontré comme agent de séchage et comme composant principale d'une couche barrière. Mots clès: Micro- et nano-fibrilles de cellulose, couche barrières, procédés d'enduction / Development of new packaging materials based on micro- and nano-fibrillated cellulose. The micro- and nanofibrillated cellulose (MFC/NFC) are nanomaterials from revewable resource with a high interest and partly for the packaging development. MFC combined both interesting properties (high tensile strength, good barrier to oxygen and grease, good transparency) and the advantages of natural cellulose source. The objective of this thesis was to develop a barrier packaging board based on MFC/NFC by coating processes. Firstly, the study focussed on the characterisation of the MFC suspensions, on the manufacturing of MFC self-standing films and on the determination of their properties. Secondly, the development of MFC based composites was studied as model films. The last part was devoted to the introduction of MFC in coating colours in order to develop a barrier layer at the board surface. Trials at pilot scale demonstrated the industrial feasibility of this product. The potential of the use of MFC/NFC was demonstrated to be used as a drying additive and a main composant of barrier layer. Keywords: Micro- and nanofibrillated cellulose, barrier layer, coating processes

Les nanocomposites à base de polymères sont utilisés depuis plusieurs années dans différents domaines industriels. Ils permettent une amélioration des propriétés des polymères et/ou l'accès à certaines propriétés presque inexistantes sur le polymère de base. Cependant, les polymères utilisés sont souvent d’origine pétrochimique. Au cours des dernières années, l'accumulation de déchets toxiques a, entre autres, conduit à un remplacement progressif de ces matières par des polymères issus des agro-ressources et/ou biodégradables. Notre étude porte sur deux polymères biodégradables utilisés comme matrice dans des nanocomposites, le poly (acide lactique) (PLA) et le poly (butylène succinate) (PBS). Elle a pour but, d'une part, d’améliorer les propriétés barrière aux gaz et à la vapeur d'eau, et d'autre part, de les rendre conducteur de chaleur. Pour ce faire, deux différents types de charges ont été utilisés. La première, la montmorillonite organiquement modifiée (OMMT) a permis d’obtenir une amélioration significative des propriétés mécaniques et barrière du polymère. La seconde, le graphite expansé (EG) a prouvé sa capacité à augmenter les propriétés de transport de chaleur dans les polymères. Une étude bibliographique a révélé que les conditions de mise en œuvre et les affinités entre les deux composés influencent considérablement les propriétés finales du nanocomposite. Ainsi les conditions de mise en œuvre ont été optimisées en faisant varier le temps et les températures de mélange de même que la méthode de mise en œuvre en fonction des charges utilisées. Pour améliorer les interactions entre la matrice et les charges, ces dernières ont été fonctionnalisées par un alkoxysilane, le 3-AminoPropylTrimethoxy-Silane. Les effets de cette fonctionnalisation sur les propriétés mécaniques, barrière, thermiques et thermophysiques des nanocomposites sont présentés. Pour les nanocomposites chargés en EG, l’effet des tailles et de la distribution des tailles des particules sur les conductivités thermiques des nanocomposites a été discuté en se basant sur un modèle de type Maxwell-Garnett basé sur la théorie des champs moyen. / Polymer based nanocomposites have been used for several years in various industrial fields. They allow an improvement of the polymer properties and/or an access to some almost non-existent properties of the neat material. However, the used polymers originated mostly from petrochemical industry. In recent years, the accumulation of toxic waste, among others, led to a gradual replacement of these materials by polymers from agro-resources and/or biodegradables. Our study focuses on two biodegradable polymers used as matrix in nanocomposites, poly (lactic acid) (PLA) and poly (butylene succinate) (PBS). It aims, on one hand, to improve their barrier properties to gases and water vapor, and on the other, to make them heat conductors. To achieve this, two different kinds of fillers were used. The first one, organically modified montmorillonite (OMMT), has achieved a significant improvement in mechanical and barrier properties of the polymer. The second one, expanded graphite (EG), has proven its ability to increase heat transport properties of polymers. A literature review has revealed that the conditions of nanocomposite preparation and the affinities between the two materials greatly influence the final properties of the nanocomposite. Thus the preparation parameters were optimized by varying the melting time and temperature as well as the preparation method according to the fillers used. To improve the interaction between the matrix and the fillers, they were functionalized with an alkoxysilane, 3-aminopropyltrimethoxy-Silane. The effects of this functionalization on the mechanical, barrier, thermal and thermophysical properties of nanocomposites are presented. For EG based nanocomposites, the EG size effect and size distribution on the thermal conductivity of nanocomposites were discussed based on a theoretical model using the Maxwell-Garnett mean-field theory.

The choice of corrosion protection system depends on the environment and needed lifetime for the product. The right corrosion protection should be selected in a sustainable point of view, since a well-selected coating system can reduce the environmental and economical impact, by using less and better material. The systems used for classifying corrosion protection often give a passed/not passed result for the number of years it is expected to last in a specific corrosive environment. In the last decades, Electrochemical Impedance Spectroscopy (EIS) has become a popular method for evaluating corrosion protection for organic coatings. EIS can collect quantitative data by monitoring the coatings electrochemical behavior over time, which can be used for optimizing the coating system. The purpose of this thesis was to try to predict how different combinations of coating layers and substrates will perform as a corrosion protection, which could provide information that can optimize the coating process. In this thesis, EIS has been used as a test method to evaluate organic coating systems for corrosion protection, by looking at barrier properties and adhesion for powder coatings on aluminum substrates. The main part of the coatings were applied in the coating plant at Fagerhult AB, but an external supplier has been used as a reference. The powders used in the coating process were based on polyester resins and the substrates were different aluminum alloys. The EIS measurements were performed in the chemistry lab at the School of Engineering at Jönköping University and depending on the sample setup was each sample evaluated for two or four weeks of testing. Two groups of samples had intact coatings and a third group had samples with an applied defect in the coating. The analysis of sample setups with intact coatings showed that the topcoat absorbed water faster than the primer. The samples showed no significant degradation in corrosion protection for the evaluated period and could thereby not provide enough information to be able to conclude which setup give the best corrosion protection over time. The samples with a defect in the coating indicated that two of the substrates provided similar adhesion in the coating-substrate interface. The coating from the external supplier was also included in the test and it showed the best adhesion of the tested samples. The main conclusion is that the coating system used at Fagerhult AB provides a very good corrosion protection. Longer testing time with EIS measurements on intact coatings is needed to be able to rank the different sample setups by failure of corrosion protection.

The theme of this work is the preparation and characterization of multilayer barrier coatings to polymer and metal substrates based on SiOx and organic molecules. It deals with the determination of their properties in terms of oxygen permeability and corrosion protection. The starting materials for the preparation of these layers are hexamethyldisiloxane, octafluorocyclobutane and 4,12-dichloro[2.2]paracyclophane. These layers have been prepared with regard to their use as barrier coatings for use in archeology, with the focus on corrosion protection of coated items and other specific requirements museums. For these samples was realized characteristic of both in terms of their physical properties – the ability to resist permeation of oxygen and in terms of their chemical composition. The fourier transformation infrared spectroscopy (FTIR), scanning elektron microscopy (SEM), oxygen transmission rate (OTR), contac angle measurement and corrosion testing were used for the above-mentioned characterisations.

Ces dernières années, une attention particulière a été portée aux polymères biodégradables et biocompatibles, notamment du point de vue écologique. Le développement de biopolymères pour des applications d'emballage alimentaire implique des exigences industrielles spécifiques telles qu’un bas prix ainsi que de bonnes propriétés mécaniques, thermiques et barrières. Le Polylactide (PLA) a attiré beaucoup d’attention car il est produit à partir de ressources naturelles renouvelables, et en raison de sa capacité de mise en œuvre et de ses bonnes propriétés mécaniques. Pour que le PLA puisse être développé à grande échelle pour des applications industrielles dans le domaine de l’emballage, ses propriétés barrières doivent être améliorées. La cristallisation est une méthode très utilisée pour améliorer les propriétés barrières mais n'est pas suffisante dans le cas du PLA. De nouvelles stratégies sont étudiées pour obtenir des effets plus importants. L'une d'entre elles consiste à confiner géométriquement le polymère jusqu’à l’échelle nano en utilisant le procédé de co-extrusion multicouche combiné éventuellement avec un recuit. Cette technologie respecte l'environnement et a déjà prouvé son efficacité pour améliorer les propriétés barrières aux gaz dans le cas d'autres polymères.Cette étude propose d'abord le développement de films PLA avec des structures cristallines différentes dans le but d'optimiser les conditions de cristallisation pour obtenir de meilleures propriétés barrières à l'oxygène. Parmi les différentes structures cristallines obtenues, la perméabilité est la meilleure lorsque le PLA a été cristallisé rapidement à partir de l’état vitreux pour atteindre un degré de cristallinité élevé et un bon découplage de la phase amorphe et cristalline. Ensuite, le PLLA a été confiné par deux polymères amorphes, le Polystyrène et le Polycarbonate. Nous avons montré que le polymère confineur peut influencer la structure cristalline et la mobilité de la phase amorphe du PLLA, influençant ainsi sa perméabilité. / In recent years, much attention has been focused on biodegradable and biocompatible polymers, particularly from an ecological viewpoint. The development of biopolymers for food-packaging applications implies ecofriendly character to specific industrial requirements as low-cost and good mechanical, thermal and barrier properties. Polylactide (PLA) has been attracting great attention, because it can be obtained from renewable sources, and due to its good process ability and mechanical properties. As one of the major challenges for high performance PLA packaging at a large scale is the improvement of its gas barrier properties, the tailoring of the PLA microstructure. Crystallization is a method used to improve barrier properties but is not sufficient in the case of PLA. New strategies are actually studied to obtained stronger effects. One of them consists in the geometrical confinement of the polymer at the molecular scale using the layer-multiplying co-extrusion process combined eventually with annealing processes to create nanometric thickness layers.This technology is environmentally friendly and has already proved its efficiency to improve the gas barrier properties in case of other polymers. This study first proposes the development of PLA films with different structures crystalline with the aim of optimize the crystallization conditions to get better oxygen barrier properties. Among the different crystalline structures obtained, permeability was better when PLA was rapidly crystallized from glass to reach a high crystallinity degree and decoupling of the amorphous and crystalline phase. Then, PLLA was confined by two amorphous polymers, polystyrene and polycarbonate, and its crystals structure and amorphous mobility was changed. We showed that the confiner polymer could influence PLLA confinement, both in the crystalline phase and in the amorphous phase, thus influencing its permeability.

De par leur faible coût, leurs propriétés mécaniques ajustables et leur potentielle transparence, les matériaux polymères sont des candidats de choix pour le packaging biomédical. Cependant, il est souvent nécessaire d'améliorer leurs propriétés barrière à O2 et H2O afin de garantir une conservation optimale du produit conditionné. Dans ce contexte, l'approche choisie a été d'associer une phase inorganique à la matrice polymère. Ainsi, après un choix des systèmes polymères les plus adaptés aux conditionnements pharmaceutiques souples d'une part et rigides d'autre part, nous avons étudié deux voies d'optimisation des propriétés barrière : le dépôt de couches minces organosiliciées à la surface du polymère et la voie nanocomposites. Le but est d'établir pour ces deux types de systèmes hétérogènes les relations Structure/Morphologie/Propriétés. Le dépôt de couches minces organosiliciées a été effectué par le procédé de dépôt chimique en phase vapeur assisté par plasma. Nous avons étudié deux types de monocouches, la première de type céramique SiOx et l'autre de type SiCH. La combinaison de ces couches sous forme d'empilements sur le substrat polymère permet, outre l'augmentation conséquente des propriétés barrière, une meilleure conservation des propriétés fonctionnelles sous des sollicitations de type thermique ou mécanique. Les nanocomposites ont été préparés par voie fondu à partir d'un poly(propylène) et de charges oxyde de zinc ou doubles hydroxydes lamellaires. Nous avons étudié les effets d'un agent compatibilisant et de modifications de surface des charges. Les propriétés barrière sont reliées à l'état de dispersion des charges et aux interactions charges/matrice / Due to their good handling properties, potential transparency and low cost, polymers are key components for the biomedical industry. However, high barrier properties towards gases or vapors are required for packaging applications in order to retain the quality of the product. To achieve the improvements in barrier properties of polymers, two different ways based on the combination of an inorganic phase with the polymer material were studied. The aim was to establish Structure/Morphology/Properties relationships. Thin inorganic coatings deposited on polymer substrates are of particular interest for improving barrier properties. In the current work, thin transparent silicon based layers were deposited on flexible polymer films by plasma-enhanced chemical vapor deposition. Monolayers (SiOx type and SiCH type) and piles with an alternation of these different monolayers were studied. The interest of multilayer barrier coatings was highlighted for higher barrier properties and resistance to solicitations such as thermal treatment or mechanical deformation. The second approach consisted in preparing poly(propylene) based nanocomposites with inorganic nanoparticles such as zinc oxide and layered double hydroxides. The transport properties of these materials depend on the quality of the filler dispersion in the polymer, but also on the interface between the fillers and the polymer matrix. Thus, the influence of a compatibilizer and of the nanoparticle surface modification was investigated on the properties of the nanocomposites

Depuis quelques années, les polyoléfines et en particulier le Polyéthylène présentent un intérêt économique qui se traduit par un marché en croissance constante. Cependant, il est souvent nécessaire d’améliorer leurs propriétés d’usage notamment pour des problématiques liées à l’industrie automobile. Dans ce contexte, une amélioration des propriétés thermomécaniques et barrière aux vapeurs et liquides du Polyéthylène sur une gamme de température étendue constitue un nouveau challenge scientifique et environnemental. Dans cette étude, nous avons tout d’abord étudié l’impact de charges inorganiques et d’un recuit à 125°C sous air sur les propriétés thermomécaniques d’un HDPE. Le deuxième axe de recherche s’est concentré sur l’amélioration des propriétés barrière aux essences de ce polymère en favorisant les charges lamellaires pour leur haut facteur de forme induisant un effet de tortuosité élevé. L’impact de ce type de charges sur les phénomènes de sorption et d’extraction a été étudié dans le but de définir une formulation à base HDPE optimale pour limiter la perte physique d’oligomères et d’antioxydants. Le but de ces travaux étant de mieux comprendre les différents mécanismes mis en jeu, nous avons cherché à établir les relations Structure / Morphologie / Propriétés pour les deux axes d’étude développés / In the recent years, the use of polyolefin and especially Polyethylene are of economic interest resulting in a growing attention concerning the improvement of its properties of use, especially for automotive application. In this context, the reinforcement of its thermomechanical properties and the improvement of its barrier properties to different fuels over an extended temperature range constitute a major scientific and environmental challenge. In this study, we first decided to analyze the impact of silica particles and of an annealing at 125°C under air atmosphere on thermomechanical properties of a HDPE. The second area of research was focused on the improvement of its barrier properties to fuels by the addition of lamellar charges known for their high aspect ratio inducing a tortuosity effect. The impact of these particles on sorption and extraction phenomena was also studied to determine an optimal HDPE-based formulation in order to limit the physical loss of oligomers and antioxidants. The guideline of this project was the determination of Structure / Morphology / Properties relationships to have a better understanding of the involved mechanisms

Plastics are a class of materials known for their cost and property advantages, increasing significantly in their usage worldwide. Unfortunately, these benefits come with an increasingly concerning environmental impact. A combination of inadequate disposal options and combinations of materials have led to environmental disasters that will impact generations. One of the worst areas for plastic waste is food packaging. Plastic as a material generally excels at durability and longevity, but as food packaging, it outlives its intended purpose by several orders of magnitude. This leads to plastic food packaging materials sitting in landfill or leading to the environment for hundreds of years. Because of this, there is a strong motivation to develop food packaging materials that are biodegradable, yet still maintain the properties that make plastic better than other classes of materials. Food packaging has many forms, but in general, the most important aspects are cost, mechanical, and oxygen and water barrier properties. To achieve an end-product that excels in these aspects, combinations of materials called composites may be developed. Nanocomposites are a subcategory of composites composed of a matrix material and nanomaterials, separate phases that interact with one another in a number of ways. This research is focused on increasing the mechanical and barrier properties of polyvinyl alcohol, the most commercially-viable biodegradable polymer. The nanomaterials used were graphene oxide (GO) and cellulose nanofibers (CNF) for mechanical and barrier reinforcement. Five sample compositions were produced: a control PVA, CNF, 1 wt% GO, 5 wt% GO, and 10 wt% GO, which were drawn down on uncoated paper and cast by themselves. Testing of these nanocomposites included oxygen transmission, mechanical, and thermal property analysis, and various solvent-interaction testing including absorption of water and oil, Cobb testing, and water vapor permeation. With the addition of CNF and GO to PVA, there was an observed increase in barrier properties through a reduction of hydrophilicity and water absorption, and oxygen permeability.

No description available.

The aim of this study was to compare the barrier properties of organic coatings with the same polymer matrix but different types of iron oxide particles, commercial and recycled. The work was carried out for the company SSAB with the aim of investigating whether the pigment Merox ferric oxide, which is produced in-house at the company during the pickling process, can be used and replace commercial iron oxide pigment. Evaluation of the barrier properties was done using electrochemical impedance spectroscopy where the capacitance of the coatings is calculated and reflects the water absorption of the coating over a period of exposure to the electrolyte. By comparing the capacitance of the different coatings, an estimation of the water transport through the different coatings was made. Complementary methods used were digital optical microscopy and scanning electron microscopy.  In this project, 6 lab samples were evaluated. In common, the samples consisted of the same metal substrate, hot-dip galvanized steel, and the binder in the coatings was polyester-melamine. Sample 1 consisted of the binder only, sample 2 contained the commercial iron oxide pigment, samples 3 and 4 consisted of Merox pigments but different levels of chlorine in the pigment. The thickness of the coatings of the 4 samples was 6 m. Sample 5 had a thicker coating of 20 m and contained Merox pigment. The last sample evaluated was a reference sample with anti-corrosive pigment with a thickness of 20 m. Furthermore, exposure tests were carried out with sample 5 to test how different electrolyte solutions affected the samples. The electrolytes tested were 1 M Na2SO4 (for reference), 1 M NaNO3 and 0.1 M NaCl.  The impedance measurements were performed in 3 parallel measurements on the samples with thinner coating (6 m) and an average of the capacitance was used to analyze how the capacitance changes over time. The results showed that sample 1 had much better barrier properties than the samples containing iron oxide pigments, although the exposure time to electrolyte was longer for this sample, the capacitance was lower. Both samples 2 and 4 increased rapidly in capacitance over a short period of time. Sample 3 had a rapid increase at the beginning which later decreased, the sample showed better barrier properties compared to samples 2 and 4. Cross-sectional studies carried out by scanning electron microscopy detected corrosion formation between the zinc and the coating on all samples with thinner coatings. Only one impedance measurement was made on samples 5 and 6, hence multiple measurements need to be performed to calculate the capacitance over time and provide complete and reliable results for these samples.  The results of the exposure tests indicated that the electrolyte used for the electrochemical impedance measurements, 1 M Na2SO4 is more corrosive than the other electrolytes tested, 1 M NaNO3 and 0.1 M NaCl. / Syftet med denna studie var att jämföra barriärsegenskaper hos organiska beläggningar med samma polymer matris men olika typer av järnoxidpartiklar, kommersiella och återvunna. Arbetet utfördes åt företaget SSAB med målet att undersöka om pigmentet Merox ferric oxide, vilket produceras internt på företaget under betningsprocessen, kan användas och ersätta kommersiellt järnoxidpigment. Utvärdering av barriärsegenskaperna gjordes med elektrokemisk impedansspektroskopi där beläggningarnas kapacitans beräknas och avspeglar vattenabsorption av beläggningen över en tidsperiod av exponering till elektrolyt. Genom att jämföra kapacitansen för de olika beläggningarna, har en estimering av vattentransporten genom de olika beläggningarna gjorts. Kompletterande metoder som användes var digitalt optiskt mikroskop och svepelektronmikroskopi.  I detta projekt utvärderades 6 labb-prover. Gemensamt bestod proverna av samma metallsubstrat, varmförzinkat stål och bindaren i beläggningarna var polyester-melamine. Prov 1 bestod endast av bindaren, prov 2 innehöll kommersiellt järnoxidpigmentet. Prov 3 och 4 bestod av Merox pigment men olika halter av klor i pigmentet. Tjockleken på beläggningarna hos de 4 proverna var 6 m. Prov 5 hade en tjockare beläggning på 20 m och innehöll Merox pigment. Det sista provet som utvärderades var ett referensprov med anti-korrosivt pigment med en tjocklek på 20 m. Vidare gjordes exponeringstester med prov 5 för att testa hur olika elektrolytlösningar påverkade proverna. Elektrolyterna som testades var 1 M Na2SO4 (som referens), 1 M NaNO3 och 0,1 M NaCl.  Impendansmätningarna utfördes i 3 parallella mätningar på proverna med tunnare beläggning (6 m) och ett medelvärde av kapacitansen användes för att analysera hur kapacitansen förändras över tiden. Resultatet visade att prov 1 hade mycket bättre barriärsegenskaper än proverna som innehöll järnoxid pigment, även fast exponeringstiden gentemot elektrolyt var längre för detta prov så var kapacitansen lägre. Både prov 2 och 4 ökade snabbt i kapacitans under en kort tidsperiod. Prov 3 hade en snabb ökning i början som senare avtog, provet visade bättre barriärsegenskaper jämfört med prov 2 och 4. Tvärsnittsstudier som genomfördes med svepelektronmikroskopi detekterade korrosionsbildning mellan zink och beläggningen på alla prover med tunnare beläggning. Endast en impedansmätning på prov 5 och 6 utfördes, därav behövs flera mätningar genomföras för att kunna beräkna kapacitansen över tid och ge fullständiga och pålitliga resultat för dessa prover.  Resultaten från exponeringstesterna visade på att elektrolyten som använts för elektrokemiska impedansmätningarna, 1 M Na2SO4 är mer korrosiv än de andra elektrolyterna som testades, 1 M NaNO3 och 0,1 M NaCl.