The purpose of this research is to test the effects of methyltrimethoxysilane coupling agent on composite material containing calcium sulfite obtained from the Southern Illinois Power Co-operative. This scrubber material and the miscanthus plant are of interest due to their use in coal burning power plants to reduce toxic emission. When calcium sulfate is passed through coal fire gas emissions it absorbs mercury and sulfur. In these composites it is used as filler to reduce cost. Miscanthus is a source of both cellulose reinforcement and some natural resin. This plant has low care requirements, little mineral content, useful energy return, and positive environmental effects. Under investigation is whether a post-cure procedure or a silane coupling agent will positively impact the composite. Hot pressing alone may not be enough to fully cure the phenolic. It is hoped that the silane will increase the strength characteristics of the composite by enhancing adhesion between the calcium sulfite and phenolic resin. Possible effects on the miscanthus by the silane will also be tested. Phenolic is being utilized because of its recycling and biodegradable properties along with cost effectiveness in mass production. Composite mechanical performance was measured through 3-point bending to measure flexural strength and strain at breakage. A dynamic mechanical analyzer (DMA) was used to find thermomechanical properties. The post-cure was found to be effective, particularly on the final composite containing silane. When methyltrimethoxysilane was added to the miscanthus prior to fabrication, it was found to reduce flexural strength and density. However the addition of methyltrimethoxysilane to the calcium sulfite altered thermo-mechanical properties to a state more like pure phenolic, with added flexibility and thermal stability.

La phytoremédiation est présentée comme une option pour gérer des sols dégradés. Les potentialités de Miscanthus × giganteus ont été évaluées, dans des conditions ex situ et in situ, avec pour objectif de produire une biomasse sur des sols agricoles fortement contaminés par Cd, Pb et Zn. Il a été dressé un bilan sur le comportement de la plante face à un gradient de contamination des sols, en intégrant les variations saisonnières et différentes pratiques agronomiques (choix du cultivar, densité de plantation, amendement biologique, fertilisation azotée). Il a aussi été étudié l’influence du miscanthus sur la mobilité des métaux dans les sols. Les résultats ont montré que la contamination des sols ne perturbe pas la croissance de M. × giganteus et le rendement de la biomasse récoltée. Le cadmium, Pb et Zn sont principalement accumulés dans les racines et d’une façon générale, M. × giganteus réduit leur transfert vers les organes aériens. Cette plante présente un bon potentiel pour la phytostabilisation des métaux et d’une façon plus globale, pour le phytomanagement. Prises individuellement, les pratiques agronomiques n’ont pas d’effet sur le comportement de la plante. En revanche, la fertilisation azotée d’une part, et l’interaction entre le cultivar et l’ajout de l’inoculum endomycorhizien d’autre part, favorise légèrement l’accumulation de Cd et Zn dans les organes aériens des cultivars étudiés. Compte tenu du caractère pérenne de la plante, il conviendrait de valider ces résultats sur le long terme, d’étudier les effets du stress métallique sur la santé de la plante et d’évaluer le devenir des polluants en lien avec l’accumulation des matières organiques dans le sol. / Phytoremediation is considered as an option for management of degraded soils. The potential of Miscanthus × giganteus were assessed in ex situ and in situ conditions, with the aim of producing biomass on agricultural soils heavily contaminated by Cd, Pb and Zn. The study mainly focused on the behavior of M. × giganteus growing on soils presenting a contamination gradient, and included seasonal variations and different agronomic practices, i.e., choice of the cultivar, planting density, biological soil amendment and nitrogen fertilization. The influence of the plant on metal mobility in soils was also assessed. The results show that soil contamination does not affect M. × giganteus growth and shoot yields. Cadmium, Pb and Zn are mainly accumulated in roots and in general M. × giganteus reduces their transfer to the aboveground organs. This plant presents therefore a great potential for metal phytostabilisation, and in a more comprehensive way, for phytomanagement. Taken individually, agronomic practices did not affect the plant behavior. However, nitrogen fertilization on one hand, and the interaction between the cultivar ad the endomycorrhizal inoculum on the other hand, increase the Cd and Zn accumulation in miscanthus organs. Given the perennial nature of the plant, long-term studies are needed to validate the present results, to assess the effects of metal-induced stress on the plant health as well as the fate of contaminants in relation to the accumulation of soil organic matter in miscanthus plantations.

There is a growing global energy demand and the society is forced to shift towards renewable energy sources due to the depletion of fossil fuels. Lignocellulosic biomass is a renewable resource available in vast amounts and could therefore have the potential to become a primary source for fuel production. Lignin, as a substantial part of the biomass, is underutilized due to its complex structure which can limit the potential of applying lignin towards value- adding products. However, one way to promote lignin valorization is to produce lignin nanoparticles (LNPs) that are considered valuable in the biomedical field. The aim of this report was to investigate if different botanical origins will affect the properties of LNPs, such as size, polydispersity index, 𝜁-potential and morphology. LNPs from Miscanthus sinensis grass lignin, obtained by the organosolv process, was successfully produced via solvent exchange and compared with LNPs from spruce organosolv lignin. The experimental part resulted in Miscanthus LNPs ranging from 133.7 to 377.4 nm, where a higher initial concentration yielded larger particles, and the average ζ- potential was -38.7 mV. This work has shown that the botanical origin will affect both size and shape of LNPs produced with the same method. Miscanthus LNPs were larger in size and ellipsoidal in shape compared to the spherical spruce LNPs. The lignin concentration influenced the particle size for both origins and the difference in LNP size became more significant as the concentration increased. However, to only explore two different types of plant origins is not sufficient enough to reach a general conclusion. Also, there are many influential steps from plant origin to LNP and to reach a more generalized conclusion, it is arguable that there is a necessity to explore and determine both the applied pulping method, the process to isolate the lignin and the method used to produce the LNPs. / Det globala energibehovet ökar och samhället tvingas därmed att växla till förnybara resurser eftersom de fossila bränslena kan ta slut. Biomassa är en förnybar resurs som finns tillgänglig i stora mängder och kan därför bli en potentiell primär energikälla. Lignin, som är en väsentlig del av biomassan, används inte i lika stor utsträckning på grund av dess komplexa struktur. Komplexiteten begränsar därför användandet av lignin i värdeskapande produkter. Men en väg för att ta tillvara på lignins värdefulla egenskaper kan vara framställandet av nanopartiklar (NP), vilket öppnar upp för användning av lignin inom det biomedicinska fältet. Syftet med den här rapporten är att undersöka om lignin från olika botaniska ursprung påverkar nanopartiklarnas egenskaper, som exempelvis storlek, polydispersitet, 𝜁-potential och morfologi. NP av lignin från gräsarten Miscanthus sinensis framställdes genom solvent exchange och jämfördes sedan med NP från granlignin. Både miscanthus- och granligninet var isolerat genom organosolvprocessen. Den experimentella delen av arbetet visade att NP from miscanthuslignin gav partiklar inom intervallet 133.7 to 377.4 nm, där högre koncentration gav större partiklar, och medelvärdet för 𝜁-potentialen var -38.7 mV. Resultatet från arbetet visade att det botaniskt ursprunget påverkar både storleken och formen på NP av lignin som framställts med samma metod. NP från miscanthuslignin var större och hade en mer elliptisk form, i jämförelse med de mer sfäriska partiklarna från granlignin. Ligninkoncentrationen påverkade partikelstorleken för båda typerna av lignin, dessutom blev skillnaden i partikelstorlek större när koncentrationen ökade. Däremot var det svårt att dra någon generell slutsats genom att bara undersöka två olika ursprung. Eftersom det finns flera steg i processen från växters ursprung till NP av lignin som kan påverka partiklarnas egenskaper kan det vara nödvändigt att utforska både den tillämpade massaprocessen, isoleringsmetoden och metoden som används för att framställa NP av lignin.

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The 2007 Energy Independence and Security Act mandates the production of 135 billion liters of transportation fuel achieved through the use of alternative energy sources. The most economically and sustainably competitive bioenergy crops will need to be high yielding, perennial species which require minimal inputs coupled with the ability to grow on marginal land. Grower adoption will be imperative to the success of this industry. Our results indicate that after three years of growth, several species including Arundo donax and Miscanthus × giganteus are able to produce up to 48.2 and 61.4 Mg ha⁻¹ dry weight of feedstock respectively. We also found that weed management may not be necessary under ideal growing conditions, but a group of herbicides appear promising for preemergence and postemergence application timings, tested under greenhouse conditions. The herbicides pyroxasulfone, sethoxydim and nicosulfuron may prove to be useful tools for the control of bioenergy crops if they escape cultivation. The potential for many of these exotic and highly competitive species to become invasive has hindered advancement of this industry. We develop a beginning framework to evaluate the potential for seeded Miscanthus × giganteus to become invasive, as no proven formula currently exists. We developed a novel methodology to assess the invasive potential of bioenergy crops across a continuum of invasiveness, which proved to be critical to the interpretation of our results. This methodology allows us to make relative comparisons of risk, evaluating our otherwise isolated results in broader context. We chose to evaluate M. × giganteus in a direct comparison with known exotic invasives, as well as with species that are known not to be invasive. We use a tiered approach, combining qualitative risk assessment models with quantitative field trials. Results from two weed risk assessment models indicate that many bioenergy feedstocks are of high risk, but agronomic crops such as Oryza sativa were also found to be high risk. Subsequent field trials indicate that seedling establishment for M. × giganteus in perennial systems may be low as only 0.1% of emerged seedlings survived after six months, while up to 10% of the invasive Microstegium vimineum survived. Spread of fertile M. × giganteus seedlings into annual systems with low competition had greater success; we observed 316 culms m⁻², at a distance of 1.5 m from the planted plot, after three years of growth. The observed spread of fertile M. × giganteus, in the low competition environment, did not differ from that of our positive control species; however, spread of fertile M. × giganteus seedlings into areas of high competition was significantly lower than our positive controls, up to 3 m from the cultivated plot. Importantly, A. donax and sterile M. × giganteus never spread from the cultivated plot. Results from our study and application of this novel methodology will help to prepare for the expansion of this burgeoning industry while providing useful information for the implementation of best management practices and improved stewardship. / Ph. D.

The recent trend in bioenergy feedstock development focuses on the use of large-statured perennial grasses that pose a relatively high risk of becoming invasive species due to the similarity in desirable agronomic traits with those of many of our worst invaders. Thus, it would be prudent to evaluate the potential ecological benefits and consequences of widespread cultivation of potentially invasive species. Miscanthus sinensis and its sterile daughter species, Miscanthus × giganteus, are two prominent bioenergy feedstock candidates due to their low input requirements and significant biomass production in a broad range of growing conditions. Despite being an extremely popular ornamental grass, and naturalizing in over half of US states, little is actually known about the biology, ecology and niche requirements of M. sinensis. Thus, the objective of our research is to characterize extant M. sinensis populations, and evaluate the niche requirements, especially in terms of the commonly limiting resources of light and soil moisture. In order to better assess the risk of M. sinensis (and subsequently M. × giganteus) cultivation, we surveyed 18 naturalized populations across the east coast to characterize habitat preferences, population structure, and plant performance across a latitudinal gradient. We found the vast majority of M. sinensis populations occurred in areas of high and low resource availability (e.g. soil nutrients and light) along roadsides and forest edges, with outlier individuals found in forest understories. We conducted a greenhouse study to compare shade and soil moisture tolerance among common ornamental cultivars and naturalized populations, where we found enhanced plant growth and vigor in naturalized biotypes compared to ornamentals across varying levels of shade. We also found that both naturalized and ornamental biotypes were not significantly affected by soil moisture stress, and thus express significant drought tolerance. Finally, we investigated the temperature and moisture requirements of M. sinensis seeds and determined a base temperature of approximately 8"C, as well as variable moisture and time to germination requirements between varieties and seed sources. These basic ecological studies will help refine and support future evaluations and weed risk assessments of both Miscanthus sinensis and M. × giganteus, which is critical in prevention of major ecological invasions. / Master of Science in Life Sciences

Les fibres naturelles telles que le coton et le lin sont utilisées depuis longtemps dans l'industrie textile. De plus, elles prennent de plus en plus d'importance dans l'industrie des composites comme substituants des fibres de verre, de carbone ou d'aramide. Cependant, les fibres naturelles doivent être modifiées pour surmonter certains inconvénients tels que l'inflammabilité, l'hydrophilie et l'oléophilie. Dans ce travail, les retardateurs de flamme (RF) phosphorés et fluoro-phosphorés sont greffés par bombardement électronique et par modification chimique sur des tissus de lin afin d’améliorer leur comportement au feu, l’hydrophobicité et l’oléophobie. L'effet de la composition chimique sur le greffage a été également évalué en utilisant des fibres de miscanthus comparativement aux tissus de lin. La réactivité de la double liaison C = C des monomères phosphorés est étudiée pour contrôler l’efficacité de greffage de différents RF. Les étapes du radiogreffage sont étudiées et contrôlées. L'efficacité de greffage a été évaluée par fluorescence X et analyse par rayons X à dispersion d'énergie (EDS) / microscopie électronique à balayage (SEM). La résonance magnétique nucléaire du proton est utilisée pour analyser l'effet de l'irradiation sur les différents monomères. Le comportement au feu des tissus modifiés est étudié en utilisant l’analyse thermogravimétrique, la microcalorimétrie de combustion, cône calorimètre et un test au feu préliminaire. Des tissus ignifuges et oléophobes ont été développés avec succès. / Many natural fibers have been used for a long time in textile industry as cotton and flax. Moreover, natural fibers are getting more importance in composites industry as a substitute for glass, carbon, or aramid fibers. However, they must be modified to overcome some disadvantages such as flammability, hydrophilicity and oleophilicity. In this work, phosphorus and fluoro-phosphorus flame retardants were grafted by e-beam radiation and chemical modification on flax fabrics to improve their flame retardancy, hydrophobicity and oleophobicity. The effect of chemical composition on grafting were also evaluated using miscanthus fibers in comparison to flax fabrics. The reactivity of the double bond C=C of the P-monomers was studied to control the grafting yield of various FRs. Radiation grafting steps were studied and controlled carefully. Grafting efficiency was assessed by X-ray fluorescence and Energy Dispersive X-Ray Analysis (EDX) / Scanning Electron Microscopy (SEM). Proton nuclear magnetic resonance was used to analyze the effect of irradiation on different monomers. Fire behavior of the modified fabrics was studied using thermogravimetric analysis, pyrolysis combustion flow calorimetry, cone calorimetry and a preliminary fire test. Flame retardant and oleophobic fabrics were successfully developed.

Cette étude se concentre sur les « Green Wood Plastic Composites » (GWPC) élaborés avec des matrices de type polyesters aliphatiques biodégradables tels que le poly(-caprolactone) PCL, le poly(acide lactique) PLA et le poly(3-hydroxybutyrate-co-3-hydroxyvalérate) PHBHV renforcées par des fibres de Miscanthus giganteus. Afin d’améliorer l‘adhésion entre les fibres végétales et les matrices thermoplastiques, une modification chimique des fibres a été mise au point. Il s’agit de greffer des chaînes de polyesters, de même nature que la matrice, à la surface des fibres végétales, en utilisant la réactivité des doubles liaisons de la lignine par des réactions de type thiol-ène. Comme ces doubles liaisons sont peu nombreuses un agent polyfonctionnel, un polythiol, a été utilisé. Ce type de greffage a permis d’obtenir une réelle augmentation des propriétés mécaniques des composites à base de PCL et de PHBHV. Différentes techniques de mise en œuvre, extrusion, mélangeage, compression et extrusion réactive ont été utilisés afin d’étudier leur influence sur les comportements mécaniques des biocomposites. L'effet de la teneur en fibres, de leur taille et de leur disposition dans la matrice ont été étudiés. Différents modèles analytiques et numériques ont été mis en œuvre pour déterminer le comportement mécanique effectif des biocomposites. Cette étude suggère que le modèle de Mori-Tanaka avec des fibres sous forme d'inclusions cylindriques constitue une bonne approximation du comportement mécanique réel des matériaux. L'utilisation de modèles à éléments finis (FE) a révélé que la transmission de la contrainte appliquée est plus efficace dans le cas de composites à fibres courtes et que les modèles 3D sont plus réalistes que les 2D correspondants. Les modèles mathématiques mis en œuvre et concernant le processus d'extrusion réactive, responsable du greffage du polymère mais également de sa réticulation semblent pouvoir estimer la fraction de la matrice réticulée. Les composites à base de PLA présentent un module d’Young comparable aux composites réalisés avec le poly(propylène) et une bonne résistance dans des conditions de vieillissement peu agressives. L'interdisciplinarité de ce travail basé sur l'association systématique des modèles numériques à la réalisation des biocomposites est une approche complète pour cerner les propriétés de ces matériaux / This study focuses on the Green Wood Plastic Composites (GWPC), manufactured using biodegradable aliphatic polyesters as matrixes, like poly(ε-caprolactone) (PCL), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) and poly(lactic acid) (PLA) reinforced with Miscanthus giganteus fibers. In order to improve the adhesion between the thermoplastic matrixes and the vegetal fibers, a chemical treatment of these last was developed. The grafting of polyesters chains of the same nature as the matrix, was carried out on the surface of vegetal fibers, using the reactivity of unsaturated bonds present in the lignin structure through the use of the thiol-ene reaction. As these double bonds are few a polyfunctional agent, a polythiol, was used. This type of grafting allowed to obtain a real increase in the mechanical properties of biocomposites realized with PCL and PHBHV. Various manufacturing techniques such as extrusion, mixing, injection, compression molding and reactive extrusion were used to study their influence on the mechanical behavior of biocomposites. The effect of fibers content, sizes and arrangement in the matrix were also studied. Different analytical and numerical models were implemented to determine the effective mechanical behavior of the biocomposites. This study suggests that a Mori-Tanaka model with fibers as cylindrical inclusions constitutes a good approximation of the real mechanical behavior of the biocomposites. The use of finite element (FE) models revealed that the transmission of the applied stress is more efficient in the case of composites with short fibers and that 3D FE models are more realistic than their corresponding 2D. Mathematical models here implemented concerning the reactive extrusion process, this last being responsible not only of the polymer grafting but also of the polymer cross-linking, seem to be able to estimate the fraction of cross-linked matrix. PLA-based composites exhibit a Young Modulus comparable to their equivalent realized with poly(propylene), showing also a good resistance to mild aging conditions. The interdisciplinarity of this work based on the systematic association of numerical models to the practical realization of the biocomposites constitutes a complete approach to determine the properties of these materials

Le climat, la qualité de l’air et la sécurité énergétique ont changé la façon de produire l’énergie, accroissant la demande en cultures énergétiques comme M. x giganteus. Néanmoins, élargir la diversité de cette espèce est nécessaire afin de couvrir une large gamme de pédo-climats. L’objectif est donc de définir des caractères d’intérêt pour mener à bien une collecte de miscanthus en Chine, un des pays où cette plante est originaire. 44 clones sauvages de trois espèces de Miscanthus (M. sinensis, M. sacchariflous, M. floridulus) ont été collectés dans différentes régions Centre, Sud et Ouest de la Chine et multipliés à Linan dans la province chinoise de Zhejiang. En France, nous avons étudié 21 clones implantés à l’INRA d’Estrées-Mons appartenant à 3 espèces (M. x giganteus, M. sinensis and M. sacchariflorus). La thèse comporte cinq chapitres. 1) La bibliographie décrit le miscanthus au niveau de sa taxonomie, de son origine géographique, de son aptitude à produire de la biomasse et de sa résistance à différents stress. 2) Les caractères les plus importants ont été identifiés pour reconnaître les espèces. 3) Nous avons découvert que les M. x giganteus ont un génome maternel commun à des M. sacchariflorus chinois. 4) Parmi les clones sauvages Chinois, M. floridulus présente le plus d’intérêt pour produire de la biomasse. 5) Enfin, nous avons mis en évidence les facteurs physiologiques et biochimiques expliquant l’effet de la disponibilité en azote sur la photosynthèse sur 3 espèces. Ainsi, la plupart des caractères qui ont été mis en évidence au sein de cette thèse vont être utiles pour la collecte de matériel végétal et les programmes de sélection du miscanthus. / Climate, air quality and energy security have recently changed the way energy is supplied and increases the demand for bioenergy crops such as M. x giganteus. However, this species needs to enlarge its diversity to fit different growth conditions. The objective is therefore to identify traits of interest to drive the collecting of miscanthus in China, one of the countries where this plant comes from. 44 wild clones of three species of Miscanthus (M. sinensis, M. sacchariflous, and M. floridulus) were collected from the different regions of central-south-east in China and were propagated in Linan of Zhejiang province of China. In France, we studied 21 clones of three species (M. x giganteus, M. sinensis and M. sacchariflorus) which were established at INRA experimental unit in Estrées-Mons. The thesis is composed of five chapters. 1) The bibliography described miscanthus on the base of its taxonomy, geographical origin, biomass production ability and resistance to different stresses. 2) The most important traits were identified for the recognition of the species. 3) We discovered that the clones of M. x giganteus had maternal genome identical to wild relatives of some of the wild M. saccahariflorus. 4) Among the wild Chinese clones, M. floridulus was the most interesting for biomass production. 5). Finally, we highlighted the physiological and biochemical factors under the influence of nitrogen supply on the photosynthesis of miscanthus. Finally, we concluded that most of the traits we highlighted here will be helpful for future germplasm collection and breeding program of miscanthus.