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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Will substituting fossil fuels with biofuels lead to a net reduction in CO2 emissions? : The case of district heating in Norrköping municipality / Ger ersättningen av fossila bränslen med biobränslen en nettosänkning i utsläpp av CO2? : Fjärrvärmefallet i Norrköpings kommun

Ljungberg, Stina January 2018 (has links)
With global warming and the international, national and local goals of reducing greenhouse gas net emissions, the phasing out of fossil fuels are of great importance. One energy source resulting in nearly no net emissions are biofuels. Residue from the forest industry, such as tops and branches, is already today in Sweden an important source of energy, especially in the district heating sector. The demand for forest residue is estimated to increase until 2050 and the potential harvest is a lot larger than what is utilized today. This master thesis tests the hypothesis of biofuels having a climate positive effect when replacing fossil fuels, despite the loss of carbon in the forest soil, which is a feedback of harvesting forest residue. The municipality of Norrköping here works as a case as they are standing in the forefront of turning towards a bio-based economy and a fossil free energy system. The biogeochemical model ForSAFE was used to study if Norrköping can replace all their fossil fuels and solid waste in the district heating for the municipality’s households and public facilities with forest residue from the forest within the municipality’s administrative boundaries. The result show that the productive forest area of the municipality does not yield enough forest residue to fulfil the energy demand from the fossil fuels and the waste. Meanwhile, the soil organic carbon was shown to be decreasing over the simulated years (2000-2300), although the loss did not exceed the emissions from the burning of the replaced fossil fuels. If the productive forest had been large enough to yield enough biomass to meet the demand, the loss of soil organic carbon would still not exceed the amount of carbon dioxide that the fossil fuels would have emitted. This indicates a positive climate effect when replacing fossil fuels with forest residue, reducing net emissions to the atmosphere. Despite the low yield of biomass compared to the energy demand from fossil fuels and waste in Norrköping, a study like this gives a projection of the biomass production and the feedbacks. These effects will be affected by different forest management scenarios and the change in climate. The silvicultural practices have however shown to have negative impacts on the Swedish Environmental Quality Objectives. Threatening the biodiversity and leaching of nutrients and chemicals, resulting in additional feedbacks downstream are examples of effects from disturbance in the forest and forest soil. It is therefore of great importance to consider the natural environment and neatly plan around forestry operations. In the end, the climatic benefit of switching to a fossil free energy system with the help of forest biofuels will have to weighted against the negative impacts. With a landscape view used and great knowledge about feedback effects when forestry planning, the input of biofuels can be a natural way to go for several municipalities in Sweden when wanting to create a bio-based economy with zero net emissions of greenhouse gases. / Med global uppvärmning och de internationella, nationella och lokala målen om reducerade växthusgasutsläpp, är utfasningen av fossila bränslen av stor betydelse. En energikälla som ger nära noll nettoutsläpp är biobränslen. Rester från skogsindustrin, som toppar och grenar (grot) är redan idag i Sverige en viktig energikälla, speciellt inom fjärrvärmesystemet. Efterfrågan på grot väntas öka fram till år 2050 och skördepotentialen är mycket större än vad som idag utnyttjas. Detta examensarbete testar hypotesen om att biobränsle är klimatpositivt när det ersätter fossila bränslen, trots kolförlusten i marken som uppstår när grot skördas. Norrköpings kommun används här som fall då de står i framkant när det gäller övergången till en biobaserad ekonomi och ett fossilfritt energisystem. Den biogeokemiska modellen ForSAFE användes för att studera om Norrköping kan byta ut alla sina fossila bränslen samt avfall, som förser kommunens invånare och offentliga lokaler medvärme och varmvatten via fjärrvärmenätet, mot grot från skogsmarkerna inom kommunens gränser. Resultatet visar att den produktiva skogsmarken i kommunen är för liten för att producera tillräckligt med grot för att ersätta allt fossilt bränsle och allt avfall. Samtidigt sjönk markkolet över de simulerade åren (2000-2300) även om förlusten inte översteg utsläppen från förbränningen av de ersatta fossila bränslena. Om den produktiva skogen hade varit stor nog att kunna ersätta de fossila bränslena såhade förlusten av markkol ändå inte varit större än utsläppen från de fossila bränslen som kunnat ersättas. Detta indikerar den klimatnytta som bytet från fossila till biobaserade bränslen ger när nettoemissioner reduceras från atmosfären. Trots den låga skördenivån av grot i förhållande till den energi som de fossila bränslena och avfallet tillför i Norrköping, kan en studie likt denna ge en uppfattning om hur mycket grot som kommer kunna produceras i framtiden och vilka effekter dessakan ha. Dessa effekter beror då på olika skördeintensitet och ett förändrat klimat. Skogsbruket har dock visat sig bidra till att försvåra att de svenska miljömålen nås. Hot mot biodiversiteten samt läckage av näringsämnen och tungmetaller som ger problem nedströms är exempel på effekter av störningar i skogen och skogsmarken. Detta gör att visad hänsyn till den naturliga miljön och god planering kring ingrepp i skogen är av stor vikt. De positiva klimateffekterna av att utnyttja biobränslen från skogen för att ersätta fossila bränslen kan därför komma att behöva ställas mot de negativa ekologiska konsekvenserna av skogsbruket. Med ett landskapsperspektiv och stor kunskap kring effekterna av skogsbruket kan biobränslet komma att bli en naturlig väg att gå för flera kommuner i Sverige som vill övergå till en biobaserad ekonomi med noll utsläpp av växthusgaser.
12

Élaboration, caractérisation et simulation de nanocomposites argile-polymère : des nouveaux matériaux pour l'éco-conception / Preparation and characterization of nano clay-biopolymer composites : new materials for eco-design

Vo, Van Son 12 December 2016 (has links)
Les nanoparticules d'argile sont des ressources naturelles largement disponibles et peu coûteuses présentant de nombreuses caractéristiques telles qu'une grande surface spécifique, une imperméabilité aux gaz, ainsi que des propriétés mécaniques et thermiques élevées. Elles ont donc attiré depuis plus de trois décennies une attention particulière, notamment pour le renforcement des matériaux à base de polymères. Cependant, les nanoparticules d'argile à l'état natif souffrent d'une incompatibilité, donc de faibles interactions interfaciales et de d'une mauvaise dispersion avec/dans la plupart des matériaux polymères organiques à cause de leur hydrophilie intrinsèque et des fortes interactions entre les feuillets constitutifs. Ainsi, l'un des principaux défis dans le développement de nanocomposites polymères à base d'argile (NAPs) avec des propriétés mécaniques avancées repose sur le contrôle au niveau à l'échelle moléculaire des propriétés interfaciales entre l'argile et la matrice polymère. En tenant compte des critères du développement durable, du génie civil et de l'économie verte, nous avons développé, dans la première partie de cette thèse, des nano-renforts réactifs et pré-exfoliés qui peuvent être incorporés dans une grande série de matrices (bio)polymères en donnant lieu à de fortes interactions avec les dites matrices et conduisant pour un à des comportements mécaniques améliorés. Afin de mieux répondre à ces spécificités, nous avons mis en oeuvre des approches vertes pour la préparation de ces nano-renforts génériques, à savoir la photopolymérisation a été utilisée comme faible consommateur d'énergie et une méthode rapide et peu énergivore pour la fonctionnalisation de surface des argiles, un protocole sans solvant a été utilisé pour préparer des nanocomposites ternaires, tandis que des biopolymères (amidon, cellulose) ou des précurseurs d'origine biologique (huiles végétales époxydées) ont servi de milieux de dispersion. Les résultats principaux issus de cette première partie peuvent être résumés comme suit : - La morphologie et la réactivité des nano-renforts d'argile sont aisément contrôlées en ajustant le temps de photo-polymérisation et en choisissant un monomère vinylique approprié. - Les méthodes de préparation permettent la préparation d'échantillons de à l'échelle des grammes. - La chimie surface des nano-renforts réactifs et pré-exfoliés peut être ajustée afin d'assurer la compatibilité avec les des biopolymères préformés thermoplastiques et des résines thermodurcissables, tels que l'amidon et les résines époxyde biosourcées, respectivement. - Les propriétés mécaniques des nanocomposites ternaires ainsi obtenus sont fortement améliorées comparés aux en comparaison des matrices polymères pures grâce à la dispersion homogène et fine des feuillets du nano-renfort dans la matrice polymère et aux fortes interactions interfaciales entre ces deux constituants / Clay nanoparticles (CNP) are abundantly available low-cost natural resources with numerous positive attributes such as large surface area, impermeability to gas, superior mechanical and thermal properties so that they have attracted over the last three decades significant attention, notably for the reinforcement of polymer-based materials. However, CNP suffer from incompatibility, hence weak interfacial interactions and poor dispersion with/in most of organic polymeric materials because of their intrinsic hydrophilicity and strong interlayer interactions. This limitation is one of the major reasons why polymer nanocomposites have to date remained mainly in laboratories. Thus, one of the key challenges in developing clay-based polymer nanocomposites (PCNs) with advanced thermo-mechanical, gas barrier...properties relies on the control at the molecular level of the interface properties of clay nanoplatelets-filled polymer resins. Taking into account the criteria for sustainable development, civil engineering and green economy, we have developed, in the first part of this thesis, reactive and pre-exfoliated clay nanofillers that may be further incorporated in a diverse set of biopolymer matrices and giving rise to strong energy interactions with the said matrices for improved mechanical behavior. To ensure a closer fit of these specifications we have implemented green approaches for the preparation of these generic nanofillers, namely photopolymerisation was used as a low energy consumption and fast method for the surface functionalization of native clays, solvent-free protocols were applied to prepare polymer nanocomposites, while biopolymers (starch, cellulose) or bio-based precursors (epoxidized vegetal oils) served as dispersion media. By controlling the preparation conditions, reactive clay nanofillers with adjustable interlayer spacing and chemical surface reactivity were prepared. Of particular interest is that the layered-like structure of the clay nano ller is preserved while the d-interlayer spacing can be increased though increasing the photopolymerization time, i.e. amount of polymer within the clay nanosheets. Our major results from the the first part can be summarized as follows: Morphology and reactivity of clay nanofillers are easily controlled though adjusting the photopolymerization time and selecting adequate vinyl monomer. - The newly preparation methods allow preparation of samples beyond the gram-scale. - Reactive and surface chemistry of pre-exfoliated clay nanofillers can be tuned to provide compatibility with both conventional preformed biopolymers and bio-based epoxy resins. - The mechanical properties of the resulting polymer nanocomposites are improved as compared to the neat polymeric matrices owing to the strong interface interaction between fillers and dispersion matrices
13

O macro-ambiente do desenvolvimento dos biocombustíveis

Málaga, Adalberto Medina January 2007 (has links)
A utilização das fontes não-renováveis de energia, como o petróleo e seus derivados, tem proporcionado elevados índices de desenvolvimento em algumas nações, mas também tem causado sérios impactos ao meio ambiente. Diante disso, este trabalho visualiza as mudanças do macro-ambiente dos biocombustíveis no transcurso do tempo, num olhar comparativo a uma rota energética proposta nos anos 30 nos Estados Unidos pelo Movimento Chemurgic. Transcorridos 70 anos de uso de derivados de petróleo, a produção e o uso de biocombustíveis passou a ser um tema de grande relevância no âmbito energético mundial, principalmente devido ao aquecimento global, ocasionado pela concentração do dióxido de carbono na atmosfera. Reporta-se no transcurso do tempo, uma clara participação das inovações tecnológicas no desenvolvimento dos biocombustíveis e dos biomateriais, cuja difusão no presente se dá sob condicionantes de natureza política e ambiental. Para tanto, procurou-se determinar a participação das variáveis de emergência econômicas, sociais, políticas, ambientais e tecnológicas que caracterizam o mencionado macro-ambiente do desenvolvimento e uso de materiais de origem agrícola na produção de combustíveis renováveis, por meio de uma analise léxica e de conteúdo na literatura científica mundial numa interpretação qualitativa dos textos científicos mediante a utilização de um software, que identificou a freqüência de citação das palavras-chave de cada dimensão estabelecida, em que a analise documental permitiu a elaboração de mapas conceituais atuais e retrospectivos, representando o comportamento e desenvolvimento dos biocombustíveis. Considera-se finalmente que, diante de uma visível deterioração ambiental, da poluição atmosférica em particular, os fatores socioeconômicos e políticos de maior importância que promoveram o uso dos biocombustíveis e os biomateriais nos anos 30, abriram lugar para os fatores de natureza ambiental que, paralelamente, promovem a ampliação da produção e do uso dos biomateriais. / The use of non-renewable sources of energy, like petroleum and its derivatives, has been providing high development levels in some nations, but also has been causing serious impacts on the environment. Thus, this work visualizes the changes on biofuel’s macro-environment through the time, in a comparative view of an energetic route proposed in the 30’s in United States by the Chemurgic Movement. Passed 70 yeas of using petroleum derivates, the production and the use of biofuel turned to be a theme of great relevance on energetic world circuit, especially because of global warming, caused by the concentration of Carbon dioxide on atmosphere. It is alluded, in the course of time, a clear participation of technological innovations on the biofuel and biomaterials’ development, whose diffusion in present time happens according to political and environmental conditioners. To do so, it attempted to stipulate the participation of the economical, social, political, environmental and technological emergent variables that characterize the mentioned macro-environment of development and use of agricultural origin materials in the renewable fuel production, through a lexical and content analysis on the world scientific literature in a qualitative interpretation of scientific texts using one Software, which set the keywords citation frequency in each established dimension, in which the documental analysis allowed to elaborate actual and retrospective conceptual maps, representing biofuel’s behavior and development. It is considered, as a conclusion, that, facing a visible environmental degradation, in particular the atmospheric pollution, the most important social-economical and political factors that promoted the use of biofuel and biomaterial in the 30’s, giving place to environmental factors that, in the same time, promote the increase of production and use of biomaterials.
14

O macro-ambiente do desenvolvimento dos biocombustíveis

Málaga, Adalberto Medina January 2007 (has links)
A utilização das fontes não-renováveis de energia, como o petróleo e seus derivados, tem proporcionado elevados índices de desenvolvimento em algumas nações, mas também tem causado sérios impactos ao meio ambiente. Diante disso, este trabalho visualiza as mudanças do macro-ambiente dos biocombustíveis no transcurso do tempo, num olhar comparativo a uma rota energética proposta nos anos 30 nos Estados Unidos pelo Movimento Chemurgic. Transcorridos 70 anos de uso de derivados de petróleo, a produção e o uso de biocombustíveis passou a ser um tema de grande relevância no âmbito energético mundial, principalmente devido ao aquecimento global, ocasionado pela concentração do dióxido de carbono na atmosfera. Reporta-se no transcurso do tempo, uma clara participação das inovações tecnológicas no desenvolvimento dos biocombustíveis e dos biomateriais, cuja difusão no presente se dá sob condicionantes de natureza política e ambiental. Para tanto, procurou-se determinar a participação das variáveis de emergência econômicas, sociais, políticas, ambientais e tecnológicas que caracterizam o mencionado macro-ambiente do desenvolvimento e uso de materiais de origem agrícola na produção de combustíveis renováveis, por meio de uma analise léxica e de conteúdo na literatura científica mundial numa interpretação qualitativa dos textos científicos mediante a utilização de um software, que identificou a freqüência de citação das palavras-chave de cada dimensão estabelecida, em que a analise documental permitiu a elaboração de mapas conceituais atuais e retrospectivos, representando o comportamento e desenvolvimento dos biocombustíveis. Considera-se finalmente que, diante de uma visível deterioração ambiental, da poluição atmosférica em particular, os fatores socioeconômicos e políticos de maior importância que promoveram o uso dos biocombustíveis e os biomateriais nos anos 30, abriram lugar para os fatores de natureza ambiental que, paralelamente, promovem a ampliação da produção e do uso dos biomateriais. / The use of non-renewable sources of energy, like petroleum and its derivatives, has been providing high development levels in some nations, but also has been causing serious impacts on the environment. Thus, this work visualizes the changes on biofuel’s macro-environment through the time, in a comparative view of an energetic route proposed in the 30’s in United States by the Chemurgic Movement. Passed 70 yeas of using petroleum derivates, the production and the use of biofuel turned to be a theme of great relevance on energetic world circuit, especially because of global warming, caused by the concentration of Carbon dioxide on atmosphere. It is alluded, in the course of time, a clear participation of technological innovations on the biofuel and biomaterials’ development, whose diffusion in present time happens according to political and environmental conditioners. To do so, it attempted to stipulate the participation of the economical, social, political, environmental and technological emergent variables that characterize the mentioned macro-environment of development and use of agricultural origin materials in the renewable fuel production, through a lexical and content analysis on the world scientific literature in a qualitative interpretation of scientific texts using one Software, which set the keywords citation frequency in each established dimension, in which the documental analysis allowed to elaborate actual and retrospective conceptual maps, representing biofuel’s behavior and development. It is considered, as a conclusion, that, facing a visible environmental degradation, in particular the atmospheric pollution, the most important social-economical and political factors that promoted the use of biofuel and biomaterial in the 30’s, giving place to environmental factors that, in the same time, promote the increase of production and use of biomaterials.
15

Synthèse, formulation et caractérisation de matrices vinylester biosourcées pour l’élaboration de matériaux composites par pultrusion / Synthesis, Functionalization and Characterization of matter of renewable origin to the development of bio-based composite material with pultrusion process

Jaillet, Fanny 24 November 2014 (has links)
Les travaux présentés concernent le développement d'un matériau composite (matrice polymère + fibre) pour l'élaboration de profilés de fenêtre mis en œuvre par un procédé de pultrusion. Dans le cadre de ces travaux, plusieurs polymères vinylester biosourcés ont été développés en tant que matrice de ce matériau composite. Une résine vinylester est réalisée en deux étapes : tout d'abord la synthèse du prépolymère vinylester, correspondant à un monomère (méth)acrylé porteur de fonctions ester et qui possède des doubles liaisons polymérisable à ses extrémités. Puis, la formulation du matériau vinylester est effectuée par le mélange du prépolymère vinylester avec un monomère copolymérisable, appelé diluant réactif. Enfin, le matériau est réticulé par polymérisation radicalaire, à l'aide d'un amorceur radicalaire.Dans un premier temps, une étude modèle a été réalisée : de la synthèse du prépolymère vinylester à partir d'une molécule modèle (DGEBA) à la formulation d'un matériau vinylester par polymérisation radicalaire. Plusieurs bioressources ont ensuite été étudiées afin de remplacer le DGEBA qui est issu du bisphénol A, composé CMR, groupe 2. La stratégie a été tout d'abord d'étudier des bioressources commercialisées, tels que les huiles végétales et le cardanol qui est un sous-produit de l'industrie de la noix de cajou. Puis un produit non biosourcé, mais non classé, du nom de TACTIX a été étudié également. Et enfin des bioressources non commercialisées actuellement, tels que l'isosorbide qui est un dérivé du sucre et le phloroglucinol, qui est extrait d'écorce d'arbres ont également été étudié pour la synthèse de prépolymère VE et de matériaux VE. Le diluant réactif le plus utilisé actuellement est le styrène, qui est un composé très volatile et classé nocif. Plusieurs diluants réactifs ont donc été testés avec les prépolymères VE synthétisés afin de remplacer le styrène par des composés peu volatiles et non nocifs. Enfin, trois matériaux composite renforcés par des fibres de lin, ont été fabriqués par mini-pultrusion, à partir des systèmes étudiés (prépolymère VE synthétisé et diluant réactif). / The study presented concern the development of composite material (polymer matrix + fibres) in order to produce windows profiles by a pultrusion process. In the context of this work, several biobased vinylester polymers have been developed as matrix of the composite material. A vinylester resin is formed in two steps: firstly the synthesis of vinylester prepolymer, corresponding to a (meth)acrylated monomer carrying an ester function and having polymerizable double bonds at its ends. Next, the formulation of vinylester material is performed by mixing the vinylester prepolymer with a copolymerizable monomer, called reactive diluent. Finally, the material is crosslinked by radical polymerization, using a radical initiator.First, a model study was conducted: in the synthesis of vinylester prepolymer from a template molecule (DGEBA) to the formulation of a vinylester material by radical polymerization. Severals bioresources were then studied in order to replace the DGEBA which is from bisphenol A, compound CMR, group 2. The strategy was first to study marketed bioresources, such as vegetable oils and cardanol which is a by-product of the cashew nut shell industry. Next, a non-biobased but not listed compound, of the name of TACTIX has also been studied. Finally, bioresources not currently marketed, such as isosorbide which is a sugar derivative and phloroglucinol, which is extracted of bark of trees have also been studied for the synthesis of VE prepolymers and VE materials. The reactive diluent the most currently used is styrene, which is a very volatile and harmful compound. Several reactive diluents were tested with the VE prepolymers synthesized in order to replace the styrene by compounds with low volatility and less harmful. Finally, three composites materials reinforced with flax fibres, were made by mini-pultrusion, from the systems studied (VE prepolymer synthesized and reactive diluent).
16

Design and synthesis of plant oil-based UV-curable acrylates for sustainable coating applications

Sung, Jonggeun January 1900 (has links)
Doctor of Philosophy / Department of Grain Science and Industry / X. Susan Sun / A demand in sustainable polymers has been increased because of the environment concerns and saving finite petroleum resources. Plant oils are promising renewable resources to produce environmentally friendly polymer applications. Soybean oil-based resins such as epoxidized soybean oil (ESO) and acrylated epoxidized soybean oil (AESO) have been well-known functionalized plant oils, but relatively low performances of their polymers and a competition with food production have been disadvantages. Thus, in this study, we designed new plant oil-based acrylates using non-food resources and achieved excellent properties of the acrylates for coatings and thermoset applications. Firstly, we developed coating materials with high mechanical, thermal and coating performances using acrylated epoxidized camelina oil (AECO) as a main acrylate monomer with various meth(acrylates) as reactive diluents Next, acrylated epoxidized cardanol modified fatty acids from camelina oil (AECFA) was successfully synthesized, and a phenolic structure with long aliphatic side chains with acrylic groups was obtained. The novel structure of AECFA provided rigidity into its polymer maintained with flexibility, and AECFA coating material showed better performances in terms of all properties such as mechanical, thermal, viscoelastic, and coating performances, as compared to commercial AESO resin. Finally, acrylated epoxidized allyl 10-undecenoate (AEAU) was developed from 10-undecenoic acid, castor oil derivative. The single fatty ester structure with di-functional acrylates of AEAU had very lower viscosity and showed better thermoset performances than those of triglyceride-based acrylates such as AESO and AECO. Thus, AEAU had a potential to an alternative to AESO for thermoset applications.
17

Développement de trois différents types de matériaux innovants à base de tannins / Developmentof three different innovative tannin-based materials

Thébault, Marion 16 December 2014 (has links)
Les tannins sont des extraits chimiques présentant une alternative naturelle aux produits chimiques de type phénol ou résorcinol issus du pétrole. Ils sont déjà utilisés industriellement pour la synthèse d’adhésifs utilisés pour la fabrication de produits à base de bois tels que les panneaux de particules et les contreplaqués, mais généralement en utilisant toujours du formaldéhyde comme durcisseur pour améliorer leur pouvoir collant. Les premiers types de produits développés dans cette thèse sont des résines adhésives pour fabriquer des panneaux de particules, synthétisées à partir de tannins de Pin Radiata et d’autres aldéhydes moins nocifs obtenus en faisant réagir de l’huile de tournesol avec de l’ozone puis avec agent réducteur. L’étude s’est portée sur les conditions de l’ozonolyse, dont les paramètres étaient nombreux, et sur les analyses des huiles obtenues, puis sur la synthèse de résines à partir de solutions de tannins. Certaines de ces résines ont été utilisées pour fabriquer des panneaux de particules qui ont été testés en cohésion interne sèche. Puis le sujet s’est orienté vers le développement de mousses rigides à base de tannins et d’alcool furfurylique dans le cadre d’un projet industriel multi-matériaux. Plusieurs formulations ont été testées pour atteindre les objectifs d’un cahier des charges, dont la finalité était d’obtenir en premier lieu des panneaux de mousse homogènes de basse densité avec de bonnes propriétés mécaniques. L’innovation apportée a été de produire ces mousses dans une presse à panneaux. Enfin, une nouvelle façon de fabriquer des polymères polyuréthanes à base de tannins a été testée en utilisant des produits chimiques moins nocifs en remplacement des isocyanates habituellement utilisés dans l’industrie. La synthèse s’est fait d’abord par une étape de carbonatation des groupes hydroxyles des tannins, puis par une réaction avec l’hexamethylènediamine. Les analyses spectrométriques montres que les produits obtenus possèdent bel et bien des liaisons uréthanes. L’étude débouché sur l’exploration de l’utilisation de tannins réagis avec de l’ammoniac pour le remplacement de l’hexaméthylènediamine afin d’obtenir de nouveaux polyuréthanes « non isocynates » avec encore plus de produits biosourcés et plus respectueux de l’environnement / Tannins are chemical extracts which represent a natural alternative to chemicals as phenol or resorcinol which are from oil resources. They are already used industrially for the synthesis of adhesives used for the manufacture of wood-based products such as particleboards and plywood, but generally always used with formaldehyde as a hardener to improve their mechanical strengths. The first products developed in this thesis are adhesive resins for the manufacture of particleboards, synthesized from Radiata Pine tannins and less hazardous aldehydes obtained by reacting sunflower oil with ozone then with a reducing agent. The study has focus first on the conditions of the ozonolysis, whose parameters are numerous, and the analysis of the oils obtained, then on the synthesis of resins with solutions of tannins. Some of these resins have been used to manufacture particleboards that have been tested in dry internal bond strength. Then the subject has been oriented toward the development of rigid tannin/furanic-based foams as part of an industrial multi-material project. Several formulations have been tested to achieve the objectives of a specification, whose first purpose is to obtain foam panels homogeneous, low in density and with good mechanical properties. The innovation has been to make these foams in a particleboard press. Finally, a new route to manufacture tannin-based polyurethane polymers has been tested by using less hazardous chemicals in replacement of isocyanates, conventionally used in the industry. The synthesis is made by a first carbonatation step of tannins hydroxyl groups and then by a reaction with hexamethylenediamine. Spectrometric analyzes have shown that the products obtained do have urethane linkages. The study led to the exploration of the use of tannins reacted with ammonia to replace hexamethylenediamine to obtain new "non isocynates" polyurethanes with more bio-based and environment-friendly chemicals
18

Élaboration et caractérisation de matériaux composites biosourcés à base de mucilage et de fibres de lin / Development and characterization of bio-based composite materials made of mucilage and flax fibres

Musa, Corentin 04 November 2019 (has links)
Les travux de thèse ont été menés dans un contexte de développement et de valorisation de la filière lin au travers de l'élaboration de nouveaux matériaux composites biosourcés à base de mucilage et de fibres de lin. Ces travaux ont conduit dans un premier temps à la synthèse de précurseurs d'isosorbide époxy et polyuréthanes comme alternative aux précurseurs toxiques conventionnels. Pour cela nous avons proposé une voie originale d'optimisation de la synthèse de diglycidyle éther d'isosorbide (DGEI) en utilisant un procédé ultrasonique. Par la suite, la comparaison des méthodes de transformation des époxys en carbonates cycliques par l'inclusion de CO₂ nous a servi de base dans l'élaboration d'un protocole efficace de conversion des DGEI en cyclocarbonates d'isosorbide (CCI) dans des conditions douces de pression et de température. Dans une seconde partie, l'extraction de composés hydrosolubles de la graine de lin a permis d'identifier la structure complexe du mucilage et les effets des paramètres d'extraction sur les propriétés physico-chimiques et thermiques du mucilage. Ensuite, pour la première fois, l'oxydation du mucilage au 2,2,6,6-tétraméthylpipéridine-1-oxyle (TEMPO) a été réalisée avec succès. Puis, nous avons pu mettre en évidence l'efficience de l'oxydation assistée par ultrasons comparée à la méthode classique lors de la montée en échelle du procédé. En vue d'améliorer la compatibilité fibre/matrice des composites à fibres végétales, des traitements appliqués sur des fibres courtes de lin ont été effectués amenant à l'individualisation des fibres et à l'amélioration de l'oxydation appliquée sur des fibres sonifiées. Ces différents matériaux ont permis de formuler un panel de nouveaux biocomposites. Les DGEI ont été valorisés par la confection d'une résine réticulée par une amine renforcée par des fibres longues de lin dont les performances sont identiques aux composites pétro-sourcés. Par la suite, la sonicationdes fibres courtes de lin a mené à l'amélioration des propriétés mécaniques de composite PLA/Lin. L'utilisation de mucilage oxydé a démontré les aspects positifs de l'incorporation du mucilage de lin dans les composites légers et résistants en compression. / The thesis was carried out in a context of development and valorisation of the flax through the conception of new bio-based composite materials made of mucilage and flax fibres. This work initially led to the synthesis of isosorbide epoxy and polyurethane precursors as an alternative to the conventional toxic precursors. For this, we proposed an original route for optimizing the synthesis of isosorbide diglycidyl ether (DGEI) using an ultrasonic process. Subsequently, the comparison of the conversion methods of epoxies into cyclic carbonates by the inclusion of CO₂ served as a basis for the development of an efficient protocol for converting DGEI into isosorbide cyclic carbonates (CCI) under moderate conditions of temperature and pressure. In the second part, the extraction of water-soluble compounds from the flaxseed allowed us to identify the complex structure of the mucilage and the effects of the extraction parameters on its physicochemical and thermal properties. Then, for the first time, oxidation of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) mucilage was successfully performed. After that, we have highlighted the enhanced efficiency of ultrasonic assisted oxidation over the conventional method when scaling up the process. In order to improve the fibre/matrix compatibility of natural fibre-based composites, different treatments of short flax fibres led to the individualizationof the fibres and to the improvement of the oxidation of sonicated fibres.These new materials allowed to formulate a series of novel biocomposites. The DGEI have been enhanced by making an amine-crosslinked resin reinforced with long flax fibres which have a comparable performance to oil-based composites. Additionally, the sonication of short flax fibres led to the improvement of the mechanical properties of PLA/Flax composite. The use of oxidized mucilage has demonstrated the beneficial aspects of flax mucilage incorporation into lightweight, compression-resistant composites.
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Lignin-Modified Phenolic Syntan: A Contributor to Our Bio-Based Solutions

Ma, Yujie, Berends, Petra, Pauli, René, Wijland, Mark, Rumnit, Roberto, Meulenbroek, Rob 26 June 2019 (has links)
Content: In order to contribute to a more sustainable leather manufacturing process and leather value chain, in 2016 Smit & zoon started its own designing process of new products through the Bio-Based innovation platform. As a logical first step, answers to several key questions have been looked for: What is Bio-Based? What is renewable? Which term and method do we use to define the Bio-Based content in the Bio-Based platform? What is biodegradable? How do our current products perform? What is our vision for future products? In the process of answering these questions and guided by the Cradle-to-Cradle (C2C) CertifiedTM program, Material Reutilization Score (MRS) was used to obtain deeper insights into the formulation and environmental performance of our leather chemicals and treated as the basis for the design of new generation bio-based chemicals. Three main focus areas are setting the tone of current activities in the Bio-based platform: 1. increasing the renewable contents of the existing product groups; 2. smart valorization of industrial side streams from biological origin and 3. improving the biodegradability of leather chemicals. While focusing on these topics, it is well-understood that a proper balance needs to be found between cost, sustainability and performance. In the meantime, leather’s end of life scenario plays a role and needs to be looked at again. One of the first results of this focused approach is our patentpending polyphenolic syntan product, in which industrial lignins are used during the chemical conversion process to replace part of the phenol (40-50 w/w%) used in the production of otherwise 100% petro-based polyphenolic retanning chemicals. We have shown that our innovative technology is compatible with most of the industrial lignins (kraft, soda, organosolv, hydrolysis) from different origins (soft/hard wood, grass, straw). The obtained polyphenolic products have real tanning power and are suitable to be used as retanning agents for various types of leather rendering good organoleptic properties with additional added value of increased bio-based content, improved biodegradability thus a higher MRS. The improved biodegradability of these products can contribute to decrease the effluent treatment load. Moreover, these products can be tailor-made to meet low emission (low free phenol, low free formaldehyde) requirements as well. In addition to the lignin-based polymers, the quickly developing project portfolio within the biobased platform manifests that Smit & zoon is making steady steps towards a largely sustainable leather value chain by 2025. Take-Away: Bio-Based products contritbute to a sustainable leather manufacturing process and leather value chain. Both the raw material renewability and product biodegradability are important parameters to evaluate the environmental impact of leather chemicals. Smit & zoon has developed a patent-pending bio-based synthan product using industrial lignins to replace part of the petro-based phenols in the production process.
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Biopolymers for a more sustainable leather

Taddei, Lorenzo, Ugolini, F., Bonino, G. P., Giacomelli, G., Franceschi, C., Bertoldini, M., Sole, R., Beghetto, V. 26 June 2019 (has links)
Content: A novel class of bio-based polymers have been developed within the LIFE BIOPOL European project aiming to replace traditional re-tanning and fat-liquoring products reducing environmental impacts and increasing the safety of leather. The purpose of the project is to enhance the recovery and reuse of different bio-derived by-products from leather and agro-industrial sector to produce eco-friendly and renewable bio-polymers with high re-tanning and fat-liquoring characteristics. The LIFE BIOPOL project aims to make bio-based polymers in order to reduce the following parameters in re-tanning phase: - 20-30% COD, - 50-60% of inorganic salts (Sulphates and Chlorides), - 90% of Cr (III) salts, - 20% of water used in the leather process. Other important goals of the project are: - reduction 70-90% of hazardous and environmental polluting substances normally found in conventional chemicals, - reactivity enhancement of 30-40% of the new biopolymers compared to the current leather - application technology, - reduction of 70-80% of the Product Environmental Footprint of the new biopolymers related to the state of the art. The vegetal biomasses and the tanned hides by-products were pretreated in order to obtain suitable building blocks for the production of bio-based polymers. Several protocols involving polymerization were used in order to achieve the synthesis of the biopolymers, which have been carried out at lab scale. Macromolecular characterization of the biopolymers was performed in order to rationalize the synthetic strategy and practical application of the products giving important parameters such as molecular weight and chemical composition of the new biopolymers. Performances of new bio-based polymers have been inspected and compared with traditional chemicals through application on different types of leather. The benefits of the new products within leather making process were evaluated through chemical analyses of re-tanning and fat-liquoring effluents. The upgrade of the developed chemistry will be performed within a new devised prototype plant specifically designed and built-up for producing the bio-based polymers at industrial scale Take-Away: Production of leather making biopolymers from biomasses and industrial by-products through Life Cycle Designed Processes

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