Studies that involve natural fiber orientation in a matrix were mostly based on regulating shear forces during mixing of fiber and matrix. This study attempts to propose a novel technique for orientating natural fibers like cellulose in a viscous polymer matrix such as polylactic acid (PLA) by applying the concepts of magnetism. Orientation of cellulose fibers in a PLA was achieved by modifying the cellulose fibers with a ferromagnetic entity and subjecting to a magnetic field. Chemically modified cellulose fibers (CLF) were oriented in dilute polylactic acid by subjecting the fiber and matrix to a magnetic field of ≈ 4T (Tesla). CLF and Microcrystalline cellulose (MCC) were oxidized with Hydrogen peroxide and further reacted with activated Ferrous sulphate heptahydrate (FeSO4.7H2O) in order to form Cellulose-Fe complexes. Chemically modified CLF was characterized by spectroscopic, thermal and morphological methods. The results from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR spectroscopy) agree that coordination bonds were formed between deprotonated and/or oxidized hydroxyl groups of cellulose and Fe2+ ions. Powder X-ray diffraction (PXRD) was used to compare the crystallinity of unmodified and modified samples of CLF. Thermal properties of modified cellulose were studied using thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC). Scanning electron microscopy (SEM) results showed that there was minimal morphological change occurred to cellulose after treatment. It was also observed that the electrical conductivity of cellulose modified with Fe 2+ was higher than that of unmodified samples. The modified CLF was then mixed with polylactic acid diluted with dichloromethane and the fibers in the matrix suspension were subjected to a magnetic field of ≈ 4T. The suspension was allowed to solvent cast inside a glass vial in the magnetic field. Morphological examination of the fiber matrix composites using confocal microscopy showed that CLF were successfully oriented along the flux direction of the magnetic field.

Studies that involve natural fiber orientation in a matrix were mostly based on regulating shear forces during mixing of fiber and matrix. This study attempts to propose a novel technique for orientating natural fibers like cellulose in a viscous polymer matrix such as polylactic acid (PLA) by applying the concepts of magnetism. Orientation of cellulose fibers in a PLA was achieved by modifying the cellulose fibers with a ferromagnetic entity and subjecting to a magnetic field. Chemically modified cellulose fibers (CLF) were oriented in dilute polylactic acid by subjecting the fiber and matrix to a magnetic field of ≈ 4T (Tesla). CLF and Microcrystalline cellulose (MCC) were oxidized with Hydrogen peroxide and further reacted with activated Ferrous sulphate heptahydrate (FeSO4.7H2O) in order to form Cellulose-Fe complexes. Chemically modified CLF was characterized by spectroscopic, thermal and morphological methods. The results from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR spectroscopy) agree that coordination bonds were formed between deprotonated and/or oxidized hydroxyl groups of cellulose and Fe2+ ions. Powder X-ray diffraction (PXRD) was used to compare the crystallinity of unmodified and modified samples of CLF. Thermal properties of modified cellulose were studied using thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC). Scanning electron microscopy (SEM) results showed that there was minimal morphological change occurred to cellulose after treatment. It was also observed that the electrical conductivity of cellulose modified with Fe 2+ was higher than that of unmodified samples. The modified CLF was then mixed with polylactic acid diluted with dichloromethane and the fibers in the matrix suspension were subjected to a magnetic field of ≈ 4T. The suspension was allowed to solvent cast inside a glass vial in the magnetic field. Morphological examination of the fiber matrix composites using confocal microscopy showed that CLF were successfully oriented along the flux direction of the magnetic field.

The awareness of environmental sustainability drives the composite industry to utilize natural fibres. Natural fibres are a readily available resource with a relatively low price. In this study natural fibre flax reinforced polylactic acid (PLA) biocomposites were made using a new technique incorporating an air-laying nonwoven process. Flax and PLA fibres were blended and converted to fibre webs in the air-laying process. Composite prepregs were then made from the fibre webs. The prepregs were finally converted to composites by compression moulding. The relationship between the main process variables and the properties of the biocomposite was investigated. It was found that with increasing flax content, the mechanical properties increased. As the moulding temperature and moulding time increased, the mechanical properties decreased. The physical, thermal and morphological properties of the biocomposites were also studied. The appropriate processing parameters for the biocomposites were established for different fibre contents. The biodegradability and water absorption properties of the composites were evaluated. The composites were incubated in compost under controlled conditions. The percentage weight loss and the reduction in mechanical properties of PLA and biocomposites were determined at different time intervals. It was found that with increasing flax content, the mechanical properties of the biocomposites decreased more rapidly during the burial trial. The increasing of flax content led to the acceleration of weight loss due to preferential degradation of flax. This was further confirmed by the surface morphology of the biodegraded composites from Scanning Electron Microscope (SEM) image analysis. This study also investigated the manufacturing of 3D PLA/Flax nonwoven prepregs by using a new system of 3D nonwoven web formation, and 3D biocomposite was made using these prepregs. A new mould unit for web and a new aluminium mould for biocomposite were developed. The physical properties of 3D biocomposites were investigated and it was found that there is no significant difference between 2D and 3D biocomposites in density and void content. The effects of fibre content and processing variables on the crushing behaviour, energy absorption and failure mode of 3D shell biocomposites were experimentally studied.

This diploma thesis was focused on the preparation and characterization of biodegradable composites based on poly-3-hydroxybutyrate (PHB) and spent coffee grounds (SCG). The aim was to prepare biocomposites based on PHB and coffee grounds. Biocomposites were prepared by solution casting in chloroform. Films with a thickness of about 150-200 µm were prepared with the addition of 20% unmodified and modified coffee grounds. The PHB/SCG films were modified by an addition of a plasticizer and a crosslinking agent or by blending with polybutylene adipate terephthalate (PBAT). The thermal properties of the films were determined by differential scanning calorimetry. The compatibility filler/polymer matrix compatibility was assessed morphologically with the naked eye. It has been found that the direct addition of spent coffee grounds to the PHB is not suitable due to the deterioration of the morphology of the film surfaces and the formation of aggregates. The compatibility between the spent coffee grounds and the PHB was improved after the addition of the plasticizer and the crosslinking agent. However, the highest compatibility between SCG and PHB was achieved in the case of esterified coffee grounds. Another way to improve the resulting morphological properties of the films thus prepared was to use coffee grounds fractions.

Shear thickening fluids have the potential to improve the effectiveness of fabric materials in body armor applications as they have shown to increase the puncture and ballistic resistance of Kevlar fabrics. However, the effect of using STFs with natural fabrics such as flax has never been studied. The rheology of STFs at varying concentrations of nanosilica dispersed in polyethylene glycol PEG was studied at different temperatures and it was found that the STFs behave as a non-Newtonian fluid in response to changes in shear rate. In this study the effectiveness on the puncture and ballistic resistance of impregnating flax fabric with STF of nanosilica in PEG were investigated. The effect of hybridization of flax and Kevlar was also investigated. The puncture and ballistic resistance of the samples treated with STFs was found to increase significantly and can be controlled by STF concentration.

It is estimated that roughly 103, 515 tons of peach waste is produced annually in the US. The majority of the waste is disposed of in landfills, which contributes to climate change as they release 93 million metric tons of CO2 equivalent. Peach waste principally consists of remaining stone and seed after flesh removal. The agro-waste includes both cellulose and lignin, which can be utilized as a filler in plastic packaging to reduce carbon footprints and material cost. The objectives of this research are (1) to develop peach flour (PF)-filled biocomposites with a polyolefin matrix using maleic anhydride-g-high density polyethylene (MAH-g-HDPE) coupling agent resin and (2) to investigate the composites’ physicomechanical, thermal, and water absorbance changes. First, preliminary experiments examined a range of PF concentrations (5-50%) and MAH concentrations (0-17%) were tested to narrow the variability of PF and MAH loading mixture in an HDPE matrix. Preliminary experiments suggested that a 2:1 ratio of PF:CR provides maximum tensile properties. Response surface methodology (RSM) was utilized to analyze and optimize the tensile strength of the PW composite. The RSM parameters were MAH loading (5-20%), PF loading (2.5-10%), and polyolefin matrix (HDPE or polypropylene). The properties of PF-HDPE biocomposites were analyzed using several instrumental analyses. Mechanical strength (including tensile strength, elongation, and Young’s modulus) and thermal properties (thermal degradation, melting point, and crystallinity), and water resistance with the addition of PF and MAH were investigated. Biocomposite mechanical properties generally resulted in a nonsignificant decrease compared to the controls. Water absorption significantly increased with PF loading (P<0.01, =0.05). PF-PP biocomposites demonstrated a shift in thermal stability with an average 9.6% increase in Td compared to its control, whereas PF-HDPE biocomposites displayed no change in Td compared to its control. PF-PP and PF-HDPE biocomposites experienced a 36.7% and 16.0% decrease, respectively, in crystallinity with PF addition. The results provided evidence that peach byproduct can be diverted from landfills and utilized a filler in a polyolefin matrix. Polyolefin biocomposites with 2.5% PF would possess comparable tensile strength to a commercially available control. PF-polyolefin biocomposites can be used for packaging, automotive, and non-weightbearing construction parts.

This is a material driven study that explores how post-processing of a 3D-printed biocomposite may increase its utility in the public furniture industry. The study thereby aims to contribute insights in material development and inspire a shift in practices that pushes the industry towards a more sustainable design process. By studying theories on sustainable development, biocomposites, and additive manufacturing, the surface defects in large-scale 3D-printing are put in relation to the industry-specific requirements placed on public furnishings. The potentials for the biocomposite to satisfy these demands are assessed using the four actions steps of material driven design. This includes hands-on exploration of several post-processing methods to minimize the material’s distinctive surface roughness. The most effective surface treatment, a combination of subtractive and additive processing, is subsequently applied in a product development phase to exemplify the feasibility of these methods in the context of furniture. This resulted in a design concept which, although a time-consuming process, proves the possibility of post-processing to influence the ability of the material to meet the requirements for public use. The increased material utility achieved in this study should, however, be considered relative to the economic and ecological consequenses associated with biocomposite processing.

Les réelles opportunités de croissance dont bénéficient les marchés liés à l'utilisation de fibres végétales en tant que renfort dans les matériaux composites sont intimement liées aux performances concurrentielles de ces fibres par rapport à celles de fibres de verre en particulier l’allégement, l’amortissement et l’isolation thermique. Dans l'industrie de la fibre de chanvre, le rouissage est le premier traitement appliqué aux plantes afin de faciliter la séparation des fibres de la partie ligneuse centrale de la tige. Ce traitement est actuellement réalisé de manière empirique en champ conduisant à l’obtention de fibres de qualité variable (couleur, morphologie, microstructure, composition biochimique, propriétés thermiques et mécaniques) ce qui constitue un frein à leur utilisation plus large dans des composites hautes performances. Par conséquent, la maîtrise du rouissage est primordiale. L’objectif de ce travail de thèse est de développer une approche globale de cette étape-clé de la production des fibres de chanvre en combinant à la fois l’étude du mécanisme biologique du rouissage, celle des caractéristiques intrinsèques des fibres et celle des émissions gazeuses et des odeurs associées à l’étape de rouissage. Différents items ont été particulièrement examinés :- L’influence de la durée du rouissage et de la période de récolte sur les caractéristiques intrinsèques des fibres de chanvre (couleur, morphologie, composition biochimique, microstructure, propriétés mécaniques, propriétés thermiques).- L’évolution des émissions de composés organiques volatils (COV) et de l'odeur lors du rouissage en champ.- La dynamique temporelle des densités de population des communautés bactériennes et fongiques pendant le rouissage- L'impact du rouissage en champ (climat méditerranéen) et du rouissage accéléré (conditions contrôlées en laboratoire) sur les propriétés microstructurales, thermiques et mécaniques d’un biocomposite polypropylène/fibre de chanvre / The natural fibres are increasingly used as reinforcements in polymer composites due to their challenging performances compared to conventional fibres in term of good specific mechanical properties, damping and thermal insulation. In the hemp industry, the retting is an upstream processing applied to the plants in order to facilitate the separation of fibres from the central woody part of the stem. This treatment is currently carried out in an empirical way in the fields that leads to a large variability in the hemp fibres instrinsic characteristics (color, morphology, biochemical composition, microstructure, thermal and mechanical properties) which limit their large use in high-performance composites. Therefore, controlling retting treatment is a crucial step. The aim of this thesis is to develop a global approach to this key step in the production of hemp fibers by combining the study of the biological mechanism of retting, the intrinsic characteristics of fibers and that of emissions volatile organic compounds and odors associated with the retting step. Different items were particularly examined:- The influence of retting duration and harvest period on the intrinsic characteristics of hemp fibers (color, morphology, biochemical composition, microstructure, mechanical and thermal properties).- The evolution of Volatile Organic Compounds (VOCs) and odors of hemp stems during field retting- Temporal dynamics of population densities of bacterial and fungal communities during retting- The impact of field retting (Mediterranean climate) and accelerated retting (controlled conditions in the laboratory) on the microstructural, thermal and mechanical properties of a polypropylene / hemp fibers biocomposite

Effective biocatalysts for the processes of the esterification of free fatty acids with methanol and technical-grade glycerol were selected and optimal conditions of biocatalysis were established. Principle technological design of free fatty acids esterification with methanol and technical-grade glycerol was developed, which can be applied by biofuel producers and other interested enterprises. The formulations of liquid fuel emulsions containing technical-grade glycerol were developed and principle technological design for the production of these emulsions was suggested. Optimal composition of biofilms containing technical-grade glycerol and deoiled rapeseed cake was determined, on the basis of which the industrial scale production of biodegradable composites can be implemented. / Vykdant tyrimus, parinkti efektyvūs biokatalizatoriai ir nustatytos optimalios laisvųjų riebalų rūgščių esterinimo metanoliu ir techniniu gliceroliu taikant biotechnologinį metodą sąlygos. Sukurtos principinės laisvųjų riebalų rūgščių esterinimo metanoliu ir techniniu gliceroliu technologijos, kurias galėtų diegti biodyzelino gamybos ar kitos suinteresuotos įmonės. Sukurta skystojo kuro emulsijų, į kurių sudėtį įeina techninis glicerolis receptūra, parengta principinė technologija šių emulsijų gamybai. Nustatyta optimali bioskaidžių plėvelių, sudarytų iš techninio glicerolio ir nuriebalintų rapsų išspaudų, formavimo mišinio sudėtis, kuria remiantis biologiškai skalių kompozitų gamyba gali būti diegiama pramonėje.

Biomateriais que promovem e auxiliam a regeneração óssea vêm ganhando grande visibilidade em pesquisas na área de engenharia tecidual, em destaque os biocompósitos a partir de cerâmicas e polímeros. Muitos desafios abrangem essa área de pesquisa, sendo o principal, criar um material que mais se assemelha ao osso, não só em sua resistência mecânica, mas também em sua bioatividade e porosidade. Esse projeto tem como foco o desenvolvimento e processamento de blocos de biocompósito formados a partir de hidroxiapatita (HAp) e fibroína de seda (FS). A fibroína de seda, obtida a partir dos casulos do bicho-da-seda, foi lavada em solução de carbonato de sódio com concentração de 5% por 30 minutos. Sua dissolução foi realizada através de solução ternária contendo cloreto de cálcio, etanol e água, na proporção molar de 1:2:8. A HAp foi co-precipitada na FS dissolvida em solução ternária através de solução de fosfato (Na2HPO4) sob agitação constante. Os blocos foram prensados manualmente e avaliou-se sua morfologia, relação Ca/P e absorção de líquido definindo a melhor proporção de %HAp e %FS. Após a determinação da proporção 75%HAp e 25% FS, os blocos foram conformados em prensa hidráulica com pressões fixas de 50 e 100 MPa. As características morfológicas foram avaliadas através de análises de MEV, porosidade, absorção de líquidos, microtomografia computadorizada (?-CT) e medição da área superficial específica (BET). As características químicas e estruturais foram analisadas por EDS, FTIR, TGA e DRX. Além disso, avaliou-se a resistência à compressão, a bioatividade e a citotoxicidade do biocompósito. Os resultados mostram que o biocompósito estudado apresenta características químicas e estruturais próxima ao osso trabecular, resistência à compressão entre 2 e 10 MPa e porosidade entre 30% e 70%, é biocompatível e possui capacidade de formação de apatita. O biomaterial em estudo apresenta-se como uma boa perspectiva na área de engenharia tecidual óssea. / Biomaterials that promote and aid bone regeneration have gained great visibility in tissue engineering research, with emphasis on biocomposites from ceramics and polymers. Many challenges cover this area, the main is being to create a material similar to bone, not only in its mechanical strength but also in its bioactivity and porosity. This project focuses on the development and processing of biocomposite blocks formed by hydroxyapatite (HAp) and silk fibroin (SF). The silk fibroin, obtained from the cocoons of the silkworm, was washed in 5% sodium carbonate solution for 30 minutes. Its dissolution was carried out through a ternary solution containing calcium chloride, ethanol and water, in a molar ratio of 1: 2: 8. The HAp was co-precipitated in SF dissolved in ternary solution through phosphate solution (Na2HPO4) under constant stirring. The blocks were manually pressed and their morphology, Ca/P ratio and liquid absorption were evaluated to determine the best HAp/FS ratio. After defined the best ratio, 75%HAp and 25% FS, blocks were formed in a hydraulic press with fixed pressures (50 and 100 MPa). The morphological characteristics were evaluated by SEM, Porosity, Liquid Absorption, Computerized Microtomography (?-CT) and specific surface area (BET). The chemical and structural characteristics were analyzed by EDS, FTIR, TGA and XRD. In addition, the compressive strength, bioactivity and cytotoxicity of the composite were evaluated. The results show a biocomposite with chemical and structural characteristics close to the trabecular bone, mechanical resistance between 2 and 10 MPa and porosity between 30% and 70%, it is biocompatible and with apatite formation capacity. The biomaterial studied presents a good perspective in the field of bone tissue engineering.