The pineapple leaf (PL) is an agricultural waste with annual output and available in abundance, whereas in 2011 were produced about three million tons, being rarely used and currently has a low commercial value. Therefore, this agro-waste deserves to be better and/or properly used. The aim of this study was to explore PL as a source of raw material for the production of cellulose nanocrystals (CN). The CN were extracted by acid hydrolysis at 45°C for 5, 30 and 60 minutes, using 20 mL of H2SO4 (9.17 M) for each gram of material. The resulting CN were characterized by crystallinity index, morphology (shape and size) and thermal stability. Among the hydrolysis conditions carried out, the best extraction time was 30 minutes, with yield of 65%. At this extraction time, the CN presented a needle-shaped nature, high thermal stability (225 °C) when compared to the thermoplastic processing temperature (about 200 °C), high crystallinity (87.3%) relative to other sources CN cellulosic derived from agricultural residues (e.g., soy hull 73.5%), an average length of 249.7 ± 51.5 nm and a diameter of 4.45 ±1.41 nm, giving an aspect ratio (L/D) of around 60. Therefore, CN obtained from PL has great potential as reinforcement in the manufacture of nanocomposites. The production of CN from this underutilized agro-waste has commercial application potential that can add value to the pineapple cultivation, generate extra income for farmers and also help in agribusiness diversification. In addition, the reuse of these residues allows a significant reduction in both the volume of waste accumulated in the environment and in the extraction of raw materials, which is against the concept of sustainable development. / A folha do abacaxi (PL) é um resíduo agrícola com produção anual e disponível em abundância, visto que em 2011 foram produzidas aproximadamente três milhões de toneladas, sendo utilizado muito raramente, tem atualmente um baixo valor comercial. Portanto, este resíduo agrícola merece ser melhor e/ou usado corretamente. O objetivo deste estudo foi o de explorar a PL, como fonte de matéria prima para a produção de nanocristais de celulose (CN). Os CN foram extraídos por meio de hidrólise ácida, a 45 °C durante 5, 30 e 60 minutos, utilizando-se 20 mL de H2SO4 (9,17 M) para cada grama de fibra de celulose purificada obtida da PL. Os CN resultantes foram caracterizados por índice de cristalinidade, morfologia (forma e tamanho), e estabilidade térmica. Entre as condições de hidrólise realizadas, o melhor tempo de extração foi de 30 minutos, com rendimento de 65%. Neste tempo de extração, os CN apresentaram-se em forma de agulha, estabilidade térmica elevada (225 °C) quando comparada a temperatura de processamento dos termoplásticos (cerca de 200 °C), elevada cristalinidade (87,3%) em relação à NC de outras fontes celulósicas oriunda de resíduos agrícolas (por exemplo, a casca de soja 73,5%), um comprimento médio (L) de 249,7 ± 51,5 nm e um diâmetro (D) de 4,45 ± 1,41 nm, dando um razão de aspecto (L/D) de cerca de 60. Por conseguinte, os CN obtidos a partir da PL têm um grande potencial como reforço na produção de nanocompósitos. A produção dos CN a partir deste resíduo agrícola subutilizado tem potencial para aplicação comercial que pode agregar valor ao cultivo de abacaxi, gerar renda extra para os agricultores e também ajudar na diversificação do agronegócio. Além disso, a reutilização desses resíduos permite uma redução significativa, tanto no volume de resíduos acumulados no meio ambiente como na extração de matérias-primas, o que vem de encontro com o conceito de desenvolvimento sustentável. / Mestre em Química

<p>Transport of gasses and liquids through polymers and composites is an important factor to be considered when designing a material for structure and packaging applications. For structural engineering applications, more focus has been given to the transportation of water, vapor and organic liquids rather than gases as diffusion of these liquids into the polymers and polymer-based composites can significantly lower service life. In addition, much attention has been given to the leaching of unreacted reactant molecules, solvents, additives, degradation products from the polymers and composites to the atmosphere (water, soil etc.). We studied the transport of volatile organic compounds and water in cured-in-place-pipe (CIPP) (a representative of FRPC) and gas permeability of highly engineered cellulose nanocrystals (CNC) films.</p> <p>Cured-in-place-pipe (CIPP) is a popular technology which uses fiber reinforced polymer composite to repair sanitary sewer, stormwater, and drinking water pipe. The liner is installed in the field and exposed to flowing water immediately after installation (curing of the liner) is done. Curing conditions dictate liner properties as undercured liners can contain unreacted styrene monomers, additives, degradation products. These agents can leach out and enter the environment (soil, water, air). The objective of this work was to investigate the curing behavior, volatile content, thermal stability of steam-cured and UV-cured CIPP liners collected from Indiana and New York installation sites. The liner specimens were also exposed to water and other aggressive environmental conditions (saltwater, concrete pore solution at 50 °C) to explore the leaching of unreacted styrene and other organic chemicals from the liners. The influence of transportation of water, salt solution and pore solution through liners on mechanical and thermo-mechanical properties was also examined to study the durability of the liners. Study suggested that the durability of the liners depends on the curing condition and exposed environment conditions.</p> <p>The function of polymer packaging materials is mainly to inhibit gas and moisture permeation through the films. Cellulose nanocrystals (CNCs) have drawn growing interest for the packaging due to their non-toxicity, abundance in nature, biodegradability and high barrier properties. The objective of this work was to corelate the alignment of CNC with free volume and barrier performance of the film. Furthermore, citric acid (CA) was added to the CNC suspensions with varying quantity to explore the effect of CA on coating quality and barrier performance of CNC coated polypropylene (PP) film. Study revealed that CA addition in CNC suspension can enhance the hydrophobicity and gas barrier performance of coated PP films while retaining the high optical transparency. </p>

<p>Concrete is in everyday life such as parking lots, buildings, bridges, and more. To keep concrete and its constituents together, binders such as cement are used. Cement’s production process is responsible for 8% of global carbon dioxide emissions as of 2018. With global warming being a severe global issue, the challenge of reducing cement carbon dioxide emissions can be greatly beneficial with even slight improvements. Various solutions to this challenge have developed over the years in the form of processing efficiency, material substitution, or material additives. Of the additives for cement and concrete that have been ventured, nanomaterials have had a strong development in recent years. Specifically, cellulose nanomaterials in the form of nanocrystals, nanofibrils, and more have demonstrated great improvement in cement’s performance resulting in a reduction in cement produced and reduction in emissions. This study expands on the knowledge of cellulose nanocrystals as an additive for cement using the formation factor methodology. Formation factor is a resistivity ratio of the specimen and pore solution that can be used in correlation to the diffusion of chloride ions through the use of the Nernst-Einstein equation. This study also investigates the effect that cellulose nanomaterials have on the mechanical properties and thermogravimetric analysis of gypsum, a material commonly used in cement production that delays the hardening of cement. </p>

M. Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / Heavy metal ions are one of the most toxic materials in the environment. Adsorption is the most used process for the removal of heavy metals from wastewater. Much research has been conducted into processes to remove heavy metals using different adsorbents. Various adsorbents have been used to remove heavy metal ions from wastewater especially those that are harmful to mankind. Zeolite, clay, activated carbon and biopolymers are the most common adsorbents used. In this research, gelatin, and cellulose nanocrystals (CNCs) were used to synthesize a hydrogel membrane to remove Cu(II) and Co(II) metal ions from mining processes wastewater. The synthetic wastewater was prepared in the laboratory to conduct the experiments. Batch experiments were conducted to obtain the optimum conditions for the Cu(II) and Co(II) metal ions. The effect of parameters such as pH, ratio, contact time, and temperature were also determined. The optimum conditions obtained were 120 min contact time for both metal ions at the temperature of 30oC, pH 5 for copper and pH 7 for cobalt. The high removal of both metals ions was obtained using the ratio 3:1 (75% Gelatin and 25% CNCs) at the temperature of 303K. The maximum adsorption capacity of Cu(II) and Co(II) was 7.6923 mg/g and 10.988 mg/g, respectively. The high percentage removal of Cu(II) and Co(II) metal ions obtained was found to be 70.5% for Cu(II) at pH 5 and 74.5% for Co(II) at pH 7. The experimental data fit well to Pseudo-first-order kinetic and Freundlich isotherm models (KF= 1.89x103 mg/g for copper and 3.7x102 mg/g for cobalt) for both metal ions. The values of energy (E) from D-R model have shown that the adsorption of both metal ions was of physical nature (E<8kJ/mol) then confirmed by the thermodynamic results (ΔH°). The kinetic diffusion models have shown that the experimental data fit well with the film diffusion (R2= 0.977 and 0.989) for both metal ions at pH 5. Negative values of ΔG°obtained for both metal ions indicate that the adsorption process was spontaneous. The positive values of ΔH° obtained showed a physical adsorption process and also indicate that the adsorption process of both metal ions was endothermic. The positive values of ΔS° indicate an increase in randomness at the solid/solution interface during adsorption.

This understanding of nanocellulose can be directly applied in future formulation design to use nanocellulose in polymer nanocomposites, foams, emulsions, latexes, gels and biomedical materials. / In this study, the potential of nanocellulose as a reinforcing agent in composite materials was investigated using atomic force microscopy (AFM). AFM was used to probe the mechanical properties of nanocelluloses and to investigate their interactions and adhesion in liquid media. Amplitude modulated-frequency modulated AFM was used to map the mechanical properties of cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs). Results showed Young’s moduli of 90 GPa and 120 GPa for CNCs and CNFs, respectively, which are comparable to literature values determined using other methods. Additionally, colloid probe AFM was implemented to observe the interactions (attractive, repulsive, steric, adhesive) between cellulose and silica colloid probes with anionic CNCs (containing either a Na+ or H+ counterion) and cationic CNCs. Colloid probe AFM measurements were carried out in five different liquid media: two salt solutions (NaCl and CaCl2) and three surfactant solutions (cationic cetyltrimethylammonium bromide, CTAB; anionic sodium dodecyl sulfate, SDS; and nonionic Triton X100). It was found that low salt concentrations resulted in electrostatic repulsion and high adhesion, whereas the reverse was observed at high salt concentrations. On the contrary, an increased surfactant concentration and increased number of surfactant aggregates (micelles, bilayers, etc.) resulted in increased adhesion. Surprisingly, the interactions were strongly dependent on the CNC counterion as surfactant adsorption seemed to be primarily driven by electrostatic interactions; CTAB adsorbed more to anionic CNCs, SDS adsorbed more to cationic CNCs and Triton X100 adsorbed minimally to all CNCs. Electrophoretic mobility and particle size data showed complementary results to colloid probe AFM, indicating that interactions between surfactants and CNC films and CNCs in suspension are closely related. This research suggests that CNCs have potential as reinforcing agents due to their high strength and the tunability of their interactions through the simple addition of salts or surfactants. This understanding can be directly applied in future formulation design to use nanocellulose in polymer nanocomposites, foams, emulsions, latexes, gels and biomedical materials. / Thesis / Master of Applied Science (MASc) / Nanocellulose is a sustainable nanomaterial most commonly extracted from plants and trees. In recent research, nanocellulose has been shown to have potential as a reinforcing agent for materials such as plastics, foams, paints and adhesives. In this study, the potential of nanocellulose was investigated using atomic force microscopy (AFM). As predicted, AFM measurements indicated that nanocellulose has a high stiffness, supporting the substitution of this biobased material in the place of metals and synthetic fibres. AFM was also used to examine particle interactions in salt and soap-like (surfactant) solutions; changes in nanocellulose size and charge were used to support the findings. Negatively charged nanocellulose interacted more with positively charged surfactants and vice versa. Low salt and high surfactant concentrations led to high adhesion and better material compatibility, which is preferred. This understanding can help us design better nanocellulose materials for future applications.

With the aim of developing a deeper understanding of particle behaviour within nano-hybrid materials, this thesis investigates the particle-particle and particle-polymer interactions that influence and control cellulose nanocrystal dispersion in aqueous and non-aqueous environments. / Cellulose nanocrystals (CNCs) are rigid rod-shaped nanoparticles derived from bio-based resources and are considered an emerging nanomaterial based on their commercial availability and favourable properties. CNCs have great potential as reinforcing agents in hybrid materials and composite applications if they are well-dispersed. Whereas colloidal stability is effectively described by established theories, dispersing nanoparticles from an aggregated state, and their interaction with polymers can be difficult to predict and control. Herein, the particle-particle and particle-polymer interactions that govern CNC dispersibility in aqueous and non-aqueous environments are examined. The surface chemistry, morphology and colloidal/thermal stability of CNCs from North American industrial producers were extensively characterized such that particle interactions could be reproducibly measured from a known starting material. Industrially produced CNCs compared well to those produced at the bench-scale, implying that laboratory results should be translatable to the development of new CNC-based products. To examine particle-particle interactions within dry CNC aggregates, a surface plasmon resonance-based platform was developed to monitor CNC film swelling in a range of solvents and salt solutions. Water was observed to interrupt particle-particle hydrogen bonding most effectively, however film stability, and ultimately particle aggregation, was maintained by strong van der Waals interactions. Moreover, particle spacing and overall film thickness was found to be independent of the CNC surface chemistries and surface charge densities examined, yet the rate of film swelling scaled with the ionic strength of the surrounding media. Polyethylene glycol (PEG) was used as a model, non-ionic, water-soluble polymer to investigate polymer adsorption to CNC surfaces in water. PEG did not adsorb to CNCs despite the abundance of hydroxyl groups, which is in direct contrast to silica particles that are well known to hydrogen bond with PEG. Combining the knowledge of both particle-particle and particle-polymer interactions, PEG nanocomposites reinforced with CNCs and silica were compared and particle dispersibility was related to composite performance. Although PEG does not adsorb to CNCs in aqueous environments, polymer adsorption does occur in dry polymer nanocomposites leading to good dispersibility and improved mechanical properties. Overall, the work presented here yields new insight into the forces that govern CNC dispersion and provides a foundation from which a variety of new CNC-based products can be developed. / Thesis / Doctor of Philosophy (PhD) / Using particles derived from renewable resources to reinforce plastics and other materials has the potential to make products lighter, stronger and more environmentally friendly. However, to make these products we need to understand how to control and distribute particles uniformly throughout hybrid/composite materials. This work uses particles extracted from trees and cotton, known as cellulose nanocrystals, to reveal which factors govern particle dispersion in reinforced composite materials. To do so, first the properties and performance of commercially available cellulose nanocrystals were extensively analyzed and compared to form the basis from which interactions can be understood. Next, particle films were measured in water, organic solvents and salt solutions to better understand how aggregated cellulose nanocrystals can be separated within composite materials. The interactions between water-soluble polymers and cellulose nanocrystals were then investigated to reveal how polymer adsorption impacts particle dispersibility. Finally reinforced polymer composites were prepared with uniformly distributed cellulose nanocrystals and the crystallization and mechanical properties were investigated. By developing a deeper understanding of the factors that control cellulose nanocrystal dispersion we can learn how to make a variety of new and improved environmentally conscious products.

Cellulose nanocrystals (CNCs) are frequently prepared by sulfuric acid hydrolysis of a purified cellulose starting material. CNC yields, however, are generally low, often below 20%. This study employs response surface methodology to optimize the hydrolysis conditions for maximum CNC yield. Two experimental designs were tested and compared: the central composite design (CCD) and the Box–Behnken design (BBD). The three factors for the experimental design were acid concentration, hydrolysis temperature, and hydrolysis time. The responses quantified were CNC yield, sulfate group density, ζ-potential, z-average diameter, and Peak 1 value. The CCD proved suboptimal for this purpose because of the extreme reaction conditions at some of its corners, specifically (1,1,1) and (–1,–1, –1). Both models predicted maximum CNC yields in excess of 65% at similar sulfuric acid concentrations (~59 wt %) and hydrolysis temperatures (~65 °C). With the BBD, the hydrolysis temperature for maximum yield lay slightly outside the design space. All three factors were statistically significant for CNC yield with the CCD, whereas with the BBD, the hydrolysis time in the range 60–150 min was statistically insignificant. With both designs, the sulfate group density was a linear function of the acid concentration and hydrolysis temperature and maximal at the highest acid concentration and hydrolysis temperature of the design space. Both designs showed the hydrolysis time to be statistically insignificant for the ζ-potential of CNCs and yielded potentially data-overfitting regression models. With the BBD, the acid concentration significantly affected both the z-average diameter and Peak 1 value of CNCs. However, whereas the z-average diameter was more strongly affected by the hydrolysis temperature than the hydrolysis time, the Peak 1 value was more strongly affected by the hydrolysis time. The CCD did not yield a valid regression model for the Peak 1 data and a potentially data-overfitting model for the z-average diameter data. A future optimization study should use the BBD but slightly higher hydrolysis temperatures and shorter hydrolysis times than used with the BBD in this study (45–65 °C and 60–150 min, respectively). / Master of Science

Le but de cette thèse était de développer de nouveaux électrolytes polymères pour une application batteries lithium métal polymère. Le premier volet concerne le développement des réseaux semi-interpénétrés à base de POE et d'un polycondensat. Ces types d'électrolytes ont permis de d'améliorer les propriétés mécaniques et les conductivités à haute et basse température. L'ajout de NCC comme renfort sur ces réseaux semi-interpénétrés a permis d'atteindre propriétés physico-chimiques intéressantes et des durées de vie élevées. De plus l'hydrogénation du polycondensat permettant de moduler sont taux de réticulation a permis d'obtenir un électrolyte (en présence du LiTFSI) présentant des conductivités de 1S.cm-1 à 90°C pour un rapport O/Li=20 et O/Li=30 avec une tenue mécanique de 0,5MPa jusqu'à 100°C. Dans le second volet une série de sels de lithium à anion organique a été synthétisée et caractérisée. Ces sels de lithium présentent des bonnes stabilités électrochimiques, thermiques et des conductivités cationiques parfois plus élevées que LITFSI en milieu polymère. Le dernier volet concerne la synthèse et la caractérisation physico-chimique des nouveaux ionomères perfluoré. Ces nouveaux ionomères à conduction cationique unipolaire sont obtenus à partir de monomères aromatiques porteurs de fonctions ioniques ayant une forte aptitude à la dissociation et des nombres de transport cationique proche de 1 à 70°C. / The aim of this thesis was to develop new polymer electrolytes for application of lithium metal polymer batteries. The first part concerns the development of semi-interpenetrating networks based on POE and a polycondensat. These types of electrolytes made it possible to improve the mechanical properties and conductivity at high and low temperatures. The addition of NCC as a reinforcement on the semi-interpenetrating network has led to interesting physicochemical properties and high cycle life for batteries.The partial hydrogenation of the polycondensat allowing the modulation of the reticulation ratio has allow to elaborate as an electrolyte (in the presence of LiTFSI) exhibiting 1S.cm-1 conductivities at 90 ° C for a ratio O/Li=20 and O/Li=30 with a mechanical strength of 0.5MPa to 100 ° C. In the second part a range of lithium with organic anion was synthesized and characterized. These lithium salts show good electrochemical and thermal stability, whereas ionics conductivities are sometimes higher than LiTFSI in polymer medium. The last part concerns the synthesis and physicochemical characterization of new perfluorinated ionomers. These new cationic ionomers with a unipolar conduction are obtained from aromatic monomers carriers ionic functional having a high ability to dissociation and cation transport numbers close to 1 at 70 ° C.

La vectorisation et le ciblage d’agents anticancéreux représentent des axes de recherche majeurs au sein du LCSN. En effet, la plupart des molécules actives utilisées en thérapie anticancéreuse sont peu sélectives des tumeurs et sont toxiques pour les cellules saines. L’élaboration de nanobiomatériaux aptes à cibler spécifiquement les tumeurs par effet EPR mais également capables de les détruire par l’action de la drogue transportée s’avère capital. Le nanovecteur utilisé est élaboré à partir des nanocristaux de cellulose (CNCx) issus de l’hydrolyse acide du coton. Une première approche a consisté à élaborer la nanoplateforme thérapeutique suivant la technique. / Targeting and drug delivery are major areas of research within the LCSN. Indeed, most of the active molecules used in cancer therapy are not very selective against tumors and are toxic to healthy cells. The development of nanobiomaterials able to specifically target tumors by EPR effect but also capable of destroying them by the action of the drug transported turns capital. In this work we achieved the binding of triphenylphosphonium cation (to target the mitochondria), hydrophobic active ingredients and a nucleic acid on cellulose nanocrystals issued from the acid hydrolysis of cotton. The first therapeutic platform synthesized according to the technique.

La synthèse et la vectorisation d’agents anticancéreux constituent des axes de recherche majeurs du LCSN. De nombreux composés naturels possèdent des propriétés anticancéreuses, mais ils sont abandonnés en raison de leur manque de sélectivité vis-à-vis des cellules cancéreuses ou de leur faible biodisponibilité. Ainsi, un grand intérêt est actuellement porté sur le développement de médicaments spécifiquement vectorisés vers les cellules cancéreuses. Les vecteurs utilisés dans ce travail sont des dérivés de polyamines et des nano objets de type β-cyclodextrines / nanocristaux de cellulose (β-CD/CNCx). Les polyamines vont permettre un ciblage actif des cellules cancéreuses grâce au système de transport de polyamine (PTS) surexprimé dans ces cellules. Les nano objets vont cibler spécifiquement les tumeurs via un ciblage passif dû à l’effet EPR. Les principes actifs employés dans cette étude sont des flavonoïdes, et plus particulièrement des chalcones. En effet, les flavonoïdes, qui constituent une large famille de composés phénoliques naturels, sont connus pour leurs nombreux effets biologiques comme les activités antioxydantes, anti-inflammatoires et anti-prolifératives.L’intérêt du LCSN à la fois pour les chalcones et les agents anticancéreux nous a conduits à concevoir de nouveaux composés antiprolifératifs vectorisés. Ce travail présente dans un premier temps la synthèse de chalcones et l’obtention de dérivés couplés aux différents vecteurs décrits précédemment (motifs polyaminés,β-CD/CNCx) ; un travail sur la synthèse d’une bis-chalcone via le couplage de Suzuki est également exposé.L’ensemble des molécules obtenues est caractérisé par des analyses RMN 1H, 13C et HRMS. Dans une seconde partie, nous présentons l’ensemble des évaluations biologiques des composés précédemment obtenus. Ces évaluations sont réalisées par un test de viabilité cellulaire (test MTT) sur quatre lignées cancéreuses : deux colorectales (HT-29 et HCT-116) et deux prostatiques (PC-3 et DU-145). / Synthesis and vectorization of anticancer agents are major research themes of LCSN. Many natural compoundspossess anti-cancer properties, but they are dropped because of their lack of selectivity to cancer cells or theirlow bioavailability. Thus, great interest is currently focused on the development of drugs specifically vectorizedto cancer cells. The vectors used in this work are polyamine derivatives and nano-objects type β-cyclodextrin /cellulose nanocrystals (β-CD/CNCx). Polyamines allow active targeting of cancer cells through the polyaminetransport system (PTS) overexpressed in these cells. Nano-objects specifically target tumors using a passivetargeting due to the EPR effect. Drugs used in this study are flavonoids, especially chalcones. Indeed,flavonoids, which constitute a large family of natural phenolic compounds, are known for their numerousbiological effects such as antioxidant, anti-inflammatory and anti-proliferative activities. The interest of LCSNfor both chalcones and anticancer agents led us to design new vectorized anti-proliferative compounds. Firstly,this work shows the synthesis of chalcones and their derivatives coupled to various above-described vectors(polyamines units, β-CD/CNCx); a work on the synthesis of a bis-chalcone through the Suzuki coupling reactionis also exposed. All molecules obtained are characterized by 1H NMR, 13C NMR and HRMS analysis. In thesecond part of this work, we present all biological evaluations of compounds previously obtained. Theseassessments are performed through a cell viability test (MTT test) on four cancer cell lines: two colorectal (HT-29 and HCT-116) and two prostate (PC-3 and DU-145) cell lines.