Cellulose nanofibrils (CNFs) are nanoscale fibers of high aspect ratio that can be isolated from a wide variety of cellulosic sources, including wood and bacterial cellulose. With high strength despite of their low density, CNFs are a promising renewable building block for the preparation of nanostructured materials and composites. To fabricate CNF-based materials with improved inherent rheological and mechanical properties and additional new functionalities, it is essential to tailor the surface properties of individual CNFs. The surface structures control the interactions between CNFs and ultimately dictate the structure and macroscale properties of the bulk material. In this thesis we have demonstrated different approaches, ranging from non-covalent adsorption and covalent chemical modification to modification of cellulose biosynthesis, to tailor the structure and surface functionalities of CNFs for the fabrication of advanced materials. These materials possess enhanced properties such as water-redispersibility, water absorbency, dye adsorption capacity, antibacterial activity, and mechanical properties. In Paper I, CNFs were modified via the irreversible adsorption of carboxymethyl cellulose (CMC). The adsorption of small amounts of CMC onto the surface of CNFs prevented agglomeration and co-crystallization of the nanofibrils upon drying, and allowed the recovery of rheological and mechanical properties after redispersion of dried CNF samples. In Paper II, CNFs bearing permanent cationic charges were prepared through quaternization of wood pulp fibers followed by mechanical disintegration. The activation of the hydroxyl groups on pulp fibers by alkaline treatment was optimized prior to quaternization. This optimization resulted in individual CNFs with uniform width and tunable cationic charge densities. These cationic CNFs demonstrated ultrahigh water absorbency and high adsorption capacity for anionic dyes. In Paper III, via a similar approach as in Paper II, CNFs bearing polyethylene glycol (PEG) were prepared by covalently grafting PEG to carboxylated pulp fibers prior to mechanical disintegration. CNFs with a high surface chain density of PEG and a uniform width were oriented to produce macroscopic ribbons simply by mechanical stretching of the CNF hydrogel network before drying. The uniform grafted thin monolayer of PEG on the surface of individual CNFs prevented the agglomeration of CNFs and facilitated their alignment upon mechanical stretching, thus resulted in ribbons with ultrahigh tensile strength and modulus. These optically transparent ribbons also demonstrated interesting biaxial light scattering behavior. In Paper IV, bacterial cellulose (BC) was modified by the addition of chitin nanocrystals (ChNCs) into the growing culture medium of the bacteria Acetobacter aceti which secretes cellulose in the form of entangled nanofibers. This led to the in situ incorporation of ChNCs into the BC nanofibers network and resulted in BC/ChNC nanocomposites exhibiting bactericidal activity. Further, blending of BC nanofibers with ChNCs produced nanocomposite films with relatively lower tensile strength and modulus compared to the in situ cultivated ones. The bactericidal activity increased significantly with increasing amount of ChNCs for nanocomposites prepared by direct mixing of BC nanofibers and ChNCs. In Paper V, CNFs were isolated from suspension-cultured wild-type (WT) and cellulose-binding module (CBM) transformed tobacco BY-2 (Nicotiana tabacum L. cv bright yellow) cells. Results from strong sulfuric acid hydrolysis indicated that CNFs from transgenic cells overexpressing CBM consisted of longer cellulose nanocrystals compared to CNFs from WT cells. Nanopapers prepared from CNFs of transgenic cells demonstrated significantly enhanced toughness compared to CNFs of WT cells. / <p>QC 20141103</p> / CARBOMAT

Ce travail est une contribution expérimentale à l'étude rhéologique et en écoulement de fluides complexes (à seuil et thixotropes) transitant dans un circuit hydraulique. Il s'agit notamment de suspensions de bentonite ainsi que des complexes bentonite/polymère. L'étude porte sur l'évolution des pertes de charge et des champs de vitesse et se situe en régime laminaire, transitoire et turbulent. L'étude a été réalisée en utilisant un vélocimètre ultrasonore Doppler pulsé développé au laboratoire. Dans la première partie expérimentale de la thèse, des mesures rhéologiques et en écoulement ont été effectuées sur des suspensions de bentonite pures (sans additifs) à différentes concentrations. A partir des essais sur boucle hydraulique, une étude détaillée est présentée sur l'évolution des coefficients de frottement et des profils de vitesse pour les différents régimes d'écoulement. Dans une seconde partie, une suspension de bentonite pure et des mélanges bentonite/CMC à différentes concentrations massiques ont été étudiées en termes de comportement rhéologique et hydrodynamique en écoulement en conduite. En ce qui concerne les mesures effectuées en boucle hydraulique, il a été montré que le polymère a des propriétés viscosifiantes en régime laminaire. Par contre, en régime turbulent, le polymère agit comme un réducteur de frottement. La dernière partie de la thèse a été consacrée à l'étude de l'influence de la température sur le comportement rhéologique des solutions de polymère et des mélanges argile/polymère. Les mesures rhéologiques à différents paliers de températures ainsi que les balayages en température ont mis en évidence le caractère thermodépendant des dispersions.

Thesis (DTech (Electrical Engineering))--Cape Peninsula University of Technology, 2011 / Ultrasonic Velocity Profiling (UVP) is both a method and a device to measure an instantaneous one-dimensional velocity profile along a measurement axis by using Doppler echography. UVP is an ideal technique since it is non-invasive, works with opaque systems, inexpensive, portable and easy to implement relative to other velocity profile measurement methods. Studies have suggested that the accuracy of the measured velocity gradient close to wall interfaces need to be improved. The reason for this is due to, depending on the installation method, distortion caused by cavities situated in front of ultrasonic transducers, measurement volumes overlapping wall interfaces, refraction of the ultrasonic wave as well as sound velocity variations. A new ultrasonic transducer, which incorporates a delay line material optimised for beam forming could reduce these problems (Wiklund, 2007). If these could be addressed, UVP could be used for the measurement of velocity profiles in complex geometries (e.g. contractions, valves, bends and other pipe fittings) where the shape of the velocity profile is critical to derive models for estimating fluid momentum and kinetic energy for energy efficient designs. The objective of this research work was to optimise the UVP system for accurate complex flow measurements by evaluating a specially designed delay line transducer and implementing advanced signal processing techniques. The experimental work was conducted at the Material Science and Technology (MST) group at the Cape Peninsula University of Technology (CPUT). This work also formed part of a collaborative project with SIK - The Swedish Institute for Food and Biotechnology. Acoustic characterisation of the ultrasonic transducers using an advanced robotic setup was done at SI K. Different concentrations of the following non-Newtonian fluids exhibiting different rheological characteristics were used for testing: carboxymethyl cellulose (CMC) solutions, kaolin and bentonite suspensions. Water was used for calibration purposes.

Orientador: Sonia Maria Alves Bueno / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-06T20:08:56Z (GMT). No. of bitstreams: 1 Bresolin_IgorTadeuLazzarotto_M.pdf: 4686617 bytes, checksum: ed7a688421b5d854024279523878c12a (MD5) Previous issue date: 2006 / Resumo: Anticorpos monoclonais são imunoglobulinas secretadas por clones de linfócitos B, normais, tumorais ou obtidos pela tecnologia de hibridomas. Os anticorpos monoclonais têm sido utilizados nas áreas analítica e terapêutica, o que implica na necessidade de sua obtenção com pureza superior a 95%. Muitos estudos têm sido realizados visando à purificação de anticorpos monoclonais, destacando-se as técnicas de adsorção seletiva, como as cromatografias de troca iônica, hidrofóbica e de afinidade. Neste trabalho aplicou-se a cromatografia de afinidade em membranas de álcool polietileno-vinílico (PEVA), comparando o desempenho dos agentes quelantes (AQ) ácido iminodiacético (IDA), ácido aspártico carboximetilado (CM-Asp) e tris-2(aminoetil)amina (TREN) com íons metálicos imobilizados na purificação de anticorpos monoclonais anti-TNP, isotipo IgG1 a partir de sobrenadante de cultura celular precipitado e dialisado. Para determinar as melhores condições de adsorção e eluição na presença de diferentes sistemas tamponantes, foram testados os quelatos AQ-Ni2+, AQ-Zn2+ e AQ-Co2+, bem como os agentes quelantes sem metal imobilizado como grupos ionogênicos. De acordo com eletroforeses SDS-PAGE e análises ELlSA das frações dos picos de proteína obtidos, as melhores condições utilizadas para a purificação foi o uso de membranas PEVA-IDA-sem metal e PEVA-CM-Asp-Zn2+, em presença de tampão Tris-HCI 50 mM a pH 7,0 e eluição por aumento de concentração de Tris, atingindo fatores de purificação de 138,9 e 103,8 e pureza de 92,3% e 68,1%, respectivamente. A partir das isotermas de adsorção, determinou-se a capacidade máxima de adsorção e a constante de dissociação dos complexos IDA-lgG1 e CM-Asp-Zn2+ -lgG1 que, de acordo com o ajuste dos parâmetros pelo modelo de Langmuir, mostraram alta capacidade de adsorção e constantes de dissociação características de sistemas de afinidade média. Com o módulo de fibras ocas, construído em nosso laboratório, determinaram-se as curvas de ruptura por meio de experimentos de filtração para os processos propostos, e os resultados obtidos demonstraram que os sistemas de fibras ocas PEVA-IDA e PEVA-GM-Asp-Zn2+ são factíveis para a purificação de anticorpos monoclonais do isotipo IgG1 / Abstract: Monoclonal antibodies are immunoglobulins produced by normal, tumoral or hybrids Iymphocytes 8 obtained by hibridoma technology. Hybridomas are resulted from the fusion of Iymphocytes B with malignant myeloma cells which express both the Iymphocyte's property of specific-antibody production and the immortal characteristic of the myeloma cells. Monoclonal antibodies have been used in analytic and therapeutic areas. This application needs highly pure antibodies. Many techniques have been studied focusing monoclonal antibodies purification. These techniques include ion exchange, hydrophobic and affinity chromatography. In this study, we applied polyethylenevinyl alcohol (PEVA) membranes in the purification of monoclonal antibody from cel! culture supematant comparing the chelating agents Iminodiacetic Acid (IDA), Carboxy-methyl Aspartic Acid (CM-Asp) and Tris-2(aminoethyl)amine) (TREN) with different immobilized metal ios, Ni2+, Zn2+ and C02+, and with different buffers. We also evaluated the adsorption and purification of monoclonal antibodies using the chelating agents as ionogenic groups. According to SDS-PAGE electrophoresis and ELlSA analysis, the higher selectivity was obtained in the presence of 50 mM Tris-HCI buffer, pH 7,0 and with elution by increasing Tris concentration, with CM-Asp-Zn2+ and IDA as ionogenic group, which provided the purification of IgG with traces of albumin, reaching purification factors of 138.9 and 103.8 and purities of 92.3% and 68.1, respectively. The adsorbent capacity and the dissociation constant of the complexes IDA-lgG1 e CM-Asp-Zn2+ -lgG1 were determinate from adsorption isotherms. According to Langmuir model, the results indicated that the matrix presents high adsorption capacity and a dissociation constant characteristic for intermediate affinity systems. We also evaluated the breaktrough curves for the proposed processes. These breaktrough curves are important to scale up procedure / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

Synthesis of monosubstituted β-cyclodextrin derivatives for medicinal applications Abstract This thesis is focused on preparation of a set of β-cyclodextrin derivatives with potential use as scaffolds for a construction of novel MRI contrast agents. Firstly, the skeleton of native β-CD was selectively persubstituted at possitions 6 and equipped with azide functions. Per-6-azido-β-CD was then monosubstituted on secondary face of the macrocycle. (E)-cinnamylbromide and propargylbromide were chosen as suitable reagents. The monosubstitution reaction afforded two types of regioisomers, substituted at position 2I -O- or 3I -O-. These regioisomers were sucessfully separated via preparative column chromatography after peracetylation of all free hydroxyl groups. 2I -O-, 3I -O-formylmethyl- and 3I -O- karboxymethyl- analogues were prepared by oxidative transformation of cinnamyl group. Finally the usability of the formylmethyl- derivative for covalent binding with suitable substrate via reductive amination was confirmed. Keywords: cyclodextrins, monosubstitution, cinnamyl, propargyl, formylmethyl, carboxymethyl, reductive amination, MRI, contrast agents

Forward osmosis (FO) is an emerging technology for water treatment due to their ability to draw freshwater using an osmotic pressure gradient across a semi-permeable membrane. However, the lack of draw agents that could both produce reasonable flux and be separated from the draw solution at a low cost stand in the way of widespread implementation. This study had two objectives: evaluate the performance of three materials — peptone, carboxymethyl cellulose (CMC), and magnetite nanoparticles (Fe3O4 NPs) — as potential draw agents, and to use multi-criteria decision matrices to systematically prioritize known draw agents from literature for research investigation. Peptone showed water flux and reverse solute flux values comparable to other organic draw agents. CMC’s high viscosity made it impractical to use and is not recommended as a draw agent. Fe3O4 NPs showed average low fluxes (e.g., 2.14 LMH) but discrete occurrences of high flux values (e.g., 14 LMH) were observed during FO tests. This result indicates that these nanoparticles have potential as draw agents but further work is needed to optimize the characteristics of the nanoparticle suspension. Separation of the nanoparticles from the product water using coagulation was shown to be theoretically possible if only electrostatic and van der Waals forces are taken into account, not steric repulsion. If coagulation is to be considered for separation, research efforts on development of nanoparticle suspensions as FO draw agents should focus on development of electrostatically stabilized nanoparticles. A combination of Fe3O4 NP and peptone showed a higher flux than Fe3O4 NPs alone, but did not produce additive or synergistic flux. This warrants further research to investigate more combinations of draw agents to achieve higher flux than that obtained by individual draw agents. Potential draw agents were prioritized by conducting a literature review of draw agents, extracting data on evaluation criteria for draw agents developed over the past five years, using these data to rank the draw agents using the Analytical Hierarchy Process (AHP) and Technique for Order of Preference by Similarity to Ideal Solutions (TOPSIS). The evaluation criteria used in the ranking matrices were water flux, reverse solute flux, replenishment cost, regeneration cost, and regeneration efficacy. The results showed that the top five ranked draw agents were P-2SO3-2Na, TPHMP-Na, PEI-600P-Na, NaCl, and NH4-CO2. The impact of the assumption made during the multi-criteria decision analysis process was evaluated through sensitivity analyses altering criterion weighting and including more criteria. This ranking system provided recommendations for future research and development on draw agents by highlighting research gaps.

>Magister Scientiae - MSc / Glucose oxidase (GOx) and horseradish peroxidase (HRP) are important enzymes for the development of amperometric enzyme linked immunosensors. The selectivity of each enzyme towards its analyte deepens its importance in determining the sensitivity of the resultant immunosensor. In designing immunosensors that have customized transducer surfaces, the incorporation with FAD and iron based enzymes ensures that electron kinetics remains optimal for electrochemical measurement. Various different immobilization strategies are used to produce response signals directly proportional to the concentration of analyte with minimal interferences. The combination of self-assembled monolayers and supramolecular chemistry affords stability and simplicity in immunosensor design. In this work, two electrochemical strategies for the detection of human chorionic gonadotropin(hCG) is presented. This involves the modification of a gold surface with a thiolated β-cyclodextrin epichlorohydrin polymer (βCDPSH) to form a supramolecular inclusion complex with ferrocene (Fc)-functionalised carboxymethyl cellulose polymer (CMC). Cyclic voltammetry indicated that ferrocene is in close proximity to the electrode surface due to the supramolecular complex formed with βCDPSH. Furthermore, strategy (a) for the detection of hCG used α-antihCG labelled (HRP) as reporter conjugate. Strategy (b) maintained the CMC bifunctionalised with Fc and recognition antibody for hCG hormone. However, the system was functionalised with a HRP enzyme and detection is done by using GOx reporter conjugates for in situ production of hydrogen peroxide. The reduction of H2O2 was used for the amperometric detection of hCG by applying a potential of 200 mV. The sensitivity and limit of detection of both strategies were calculated from calibration plots. For strategy (a) the LOD was found to be 3.7283 ng/mL corresponding to 33.56 mIU/mL and a sensitivity of 0.0914 nA ng-1 mL-1. The corresponding values for strategy (b) are 700 pg/mL (6.3 mIU/mL) and 0.94 nA ng-1 mL-1.

Chitosan is a biocompatible and biodegradable mucoadhesive polymer with unique advantages, such as the distinct trait of opening the junctions to allow paracellular transport of antigen and good tolerability. However, the poor solubility of chitosan in neutral or alkalinized media has restricted its applications in the pharmaceutical field. Chitosan can be easily carboxymethylated to improve its solubility in aqueous media, while its biodegradability and biocompatibility are preserved. Apart from this, carboxymethyl chitosan (CMCS) can be easily processed into nanoparticles which highlight its suitability and extensive usage for preparing different drug delivery formulations. The present study deals with the development and characterization of a delivery system based on CMCS nanoparticles using ovalbumin as model protein. We demonstrated that ovalbumin loaded nanoparticles were successfully synthetized using calcium chloride as a cross-linker by ionic gelation. The nanoparticles exhibited an average size of approximately 169 nm and presented a pseudo-spherical shape. The nanoparticles size increased according to the addition of CaCl2 due to the strong electrostatic attraction. During storage the nanoparticles size increased was attributed to swelling and aggregation. The loading efficiency of ovalbumin was found to be 17%. Confocal microscopy clearly showed the association between ovalbumin and CMCS chains into nanoparticles. Therefore, we suggest these nanoparticles can be considered as an attractive and promising carrier candidate for proteins and antigens. The major challenge that limits the use of such carriers is their instability in an aqueous medium. Thus, the next step of this work was to determine the robustness of several formulations using distinct freeze-drying protocols. This study demonstrated that mannitol in concentration of 10% (w/v) is well suited to preserve ovalbumin loaded CMCS nanocapsules from aggregation during lyophilization and subsequent reconstitution. Importantly, the results showed that an annealing step has a huge impact on porosity of freeze-dried cake by nearly complete crystallization of mannitol, once the crystalline matrix prevents the partial collapse and the formation of larger pores observed without annealing. Therefore, the usual observation that annealing increases the pore size due to growth of ice crystal size does not always apply, at least when crystallization of solute is involved. Since all characterizations and stability studies had been performed, the main purpose of this study was to develop a stable antigen delivery system for oral immunization using CMCS and inactivated rabies virus (RV) as the antigen. RV loaded nanoparticles was found to enhance both systemic (IgG) and local (IgA) immune responses against RV after oral delivery in mice. The effective doses 50% were 50-times higher than the negative controls, indicating that the immune response started only after the third boosting dose. Furthermore, enough neutralizing antibodies was produced to be protected against the harmful effects of the rabies virus. It is therefore concluded, that the CMCS nanoparticles formulated in this study, are suitable for oral vaccine delivery, and can be suggested as a promising delivery system for a diverse range of antigens as well as a gene/protein delivery system, especially for those positively charged. Since several approaches show that effective intervention in airway allergic inflammation can be achieved with allergen-activated interleukin-10-secreting cells, the final part of this work was dedicated to assessing whether IL-10 loaded chitosan nanoparticles (IL10-CSNPs) could be used as a possible inhalable therapeutic tool for preventing exacerbations in asthmatic patients. As positive controls, we also assess whether interleukin 17A and interleukin 9 have the ability to stimulate human airway smooth muscle (HASM) cell contractility using magnetic twisting cytometry (MTC). Significant decreased baseline cell stiffness was observed in HASM cells pre-treated with IL-10, but not with IL10-CSNPs, whereas treatment with IL-17A significantly enhanced baseline cell stiffening. Our findings reveal a previously unknown mechanism underlying immunotherapy for prevention and treatment of asthma. / A quitosana é um polímero mucoadesivo biocompatível e biodegradável, com vantagens únicas, tais como a característica distinta de abrir as junções que permitim o transporte paracelular de antígenos e boa tolerabilidade. No entanto, sua baixa solubilidade em meios neutros ou alcalinizados tem restringido suas aplicações no campo farmacêutico. A quitosana pode ser facilmente carboximetilada para melhorar de sua solubilidade em meios aquosos, enquanto sua biodegradabilidade e biocompatibilidade são preservadas. Além disso, a carboximetilquitosana (CMCS) pode ser facilmente processada na forma de nanopartículas, o que destaca sua adequabilidade para uso extensivo no preparo de sistemas de delivery de medicamentos. O presente estudo trata do desenvolvimento e caracterização de um sistema de delivery baseado em nanopartículas de CMCS utilizando ovalbumina como proteína modelo. Nós demonstramos que as nanopartículas carregadas com ovalbumina foram sintetizadas com sucesso utilizando cloreto de cálcio como agente de reticulação por gelificação iônica. As nanopartículas exibiram um tamanho médio de aproximadamente 169 nm e apresentaram uma forma pseudo-esférica. O tamanho das nanopartículas aumentou de acordo com a adição de CaCl2 devido à forte atração eletrostática. Durante o armazenamento, o tamanho aumentado das nanopartículas foi atribuído a incorporação de água e agregação. A eficiência de encapsulamento da ovalbumina foi de aproximadamente 17%. A microscopia confocal mostrou claramente a associação entre ovalbumina e a cadeias de CMCS nas nanopartículas. Sugerimos, portanto, que tal sistema pode ser considerado como candidato atraente e promissor para o carreamento de proteínas e antígenos. O principal desafio que limita o uso desses carreadores consiste na instabilidade em meio aquoso. Assim, o próximo passo deste trabalho foi determinar a robustez de várias formulações utilizandose diferentes protocolos de liofilização. Este estudo demonstrou que o manitol em uma concentração de 10% (p/v) é adequado para preservar da agregação as nanocápsulas de CMCS carregadas com ovalbumina durante a liofilização e subsequente reconstituição. Mais importante, os resultados mostraram que uma etapa de annealing tem um enorme impacto sobre a porosidade da amostra liofilizada devido a quase completa cristalização do manitol, uma vez que a matriz cristalina evita o colapso parcial e a formação de poros maiores observados na ausência do annealing. Portanto, a observação comum de que o annealing aumenta o tamanho doporos devido ao crescimento dos cristais de gelo nem sempre se aplica, pelo menos quando a cristalização de um soluto está envolvida. Uma vez que todas as caracterizações e estudos de estabilidade foram realizados, o principal objetivo deste estudo foi desenvolver um sistema estável de delivery de antígeno para imunização oral utilizando CMCS e vírus rábico inativado (RV) como antígeno. Verificou-se que as nanopartículas carregadas com RV aumentam as respostas imune sistêmica (IgG) e local (IgA) contra o RV após administração oral em camundongos. As doses efetivas 50% foram 50 vezes maiores que os controles negativos, indicando que a resposta imune foi iniciada apenas após a terceira dose da vacina. Além disso, foram produzidos anticorpos neutralizantes suficientes para proteção contra os efeitos nocivos do vírus rábico. Conclui-se, portanto, que as nanopartículas de CMCS formuladas neste estudo, são adequadas para o delivery oral de vacinas, e podem ser sugeridas como um sistema promissor de delivery para uma gama diversa de antígenos, bem como para o delivery de genes/proteínas, especialmente para aqueles carregados positivamente. Uma vez que diversas abordagens mostram que uma intervenção efetiva em casos de inflamação alérgica de vias aéreas pode ser conseguida por meio de células secretoras de interleucina 10 (IL-10) mediante ativação por alergenos, a parte final deste trabalho esteve dedicada a avaliação de nanopartículas de quitosana carregadas com IL-10 (IL10-CSNPs) como possível ferramenta terapêutica inalável para prevenção de exacerbações em pacientes asmáticos. Como controles positivos, avaliou-se adicionalmente se as interleucinas 17A (IL-17A) e 9 (IL-9) possuem a capacidade de estimular a contratilidade de células humanas de músculo liso de vias aéreas humanas (HASM) por meio de citometria de torção magnética (MTC). Uma diminuição significativa da rigidez celular basal foi observada em células HASM pré-tratadas com IL-10, mas não com IL10-CSNPs, enquanto que o tratamento com IL-17A aumentou significativamente a magnitude rigidez celular basal. Nossos resultados revelam um mecanismo previamente desconhecido subjacente à imunoterapia para prevenção e tratamento da asma.

Made available in DSpace on 2014-12-17T15:42:31Z (GMT). No. of bitstreams: 1 BrunaVL_TESE.pdf: 4965695 bytes, checksum: f511eb063b5cd567f364bc0ec9385727 (MD5) Previous issue date: 2014-05-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Sustainable development is a major challenge in the oil industry and has aroused growing interest in research to obtain materials from renewable sources. Carboxymethylcellulose (CMC) is a polysaccharide derived from cellulose and becomes attractive because it is water-soluble, renewable, biodegradable and inexpensive, as well as may be chemically modified to gain new properties. Among the derivatives of carboxymethylcellulose, systems have been developed to induce stimuli-responsive properties and extend the applicability of multiple-responsive materials. Although these new materials have been the subject of study, understanding of their physicochemical properties, such as viscosity, solubility and particle size as a function of pH and temperature, is still very limited. This study describes systems of physical blends and copolymers based on carboxymethylcellulose and poly (N-isopropylacrylamide) (PNIPAM), with different feed percentage compositions of the reaction (25CMC, 50CMC e 75CMC), in aqueous solution. The chemical structure of the polymers was investigated by infrared and CHN elementary analysis. The physical blends were analyzed by rheology and the copolymers by UV-visible spectroscopy, small-angle X-ray scattering (SAXS), dynamic light scattering (DLS) and zeta potential. CMC and copolymer were assessed as scale inhibitors of calcium carbonate (CaCO3) using dynamic tube blocking tests and chemical compatibility tests, as well as scanning electron microscopy (SEM). Thermothickening behavior was observed for the 50 % CMC_50 % PNIPAM and 25 % CMC_75 % PNIPAM physical blends in aqueous solution at concentrations of 6 and 2 g/L, respectively, depending on polymer concentration and composition. For the copolymers, the increase in temperature and amount of PNIPAM favored polymer-polymer interactions through hydrophobic groups, resulting in increased turbidity of polymer solutions. Particle size decreased with the rise in copolymer PNIPAM content as a function of pH (3-12), at 25 ?C. Larger amounts of CMC result in a stronger effect of pH on particle size, indicating pH-responsive behavior. Thus, 25CMC was not affected by the change in pH, exhibiting similar behavior to PNIPAM. In addition, the presence of acidic or basic additives influenced particle size, which was smaller in the presence of the additives than in distilled water. The results of zeta potential also showed greater variation for polymers in distilled water than in the presence of acids and bases. The lower critical solution temperature (LCST) of PNIPAM determined by DLS corroborated the value obtained by UV-visible spectroscopy. SAXS data for PNIPAM and 50CMC indicated phase transition when the temperature increased from 32 to 34 ?C. A reduction in or absence of electrostatic properties was observed as a function of increased PNIPAM in copolymer composition. Assessment of samples as scale inhibitors showed that CMC performed better than the copolymers. This was attributed to the higher charge density present in CMC. The SEM micrographs confirmed morphological changes in the CaCO3 crystals, demonstrating the scale inhibiting potential of these polymers / O desenvolvimento sustent?vel ? um dos principais desafios da ind?stria do petr?leo, que tem despertado crescente interesse por pesquisas para obten??o de novos materiais provenientes de fontes renov?veis. A carboximetilcelulose (CMC) ? um polissacar?deo derivado da celulose, que se destaca por ser sol?vel em ?gua, renov?vel, biodegrad?vel, de baixo custo e por apresentar possibilidades de modifica??es em sua estrutura qu?mica. Dentre os derivados de carboximetilcelulose, alguns sistemas t?m sido desenvolvidos para induzir propriedades est?mulos-responsivos e ampliar a aplicabilidade desses materiais multirresponsivos. Embora esses novos materiais sejam atualmente objeto de estudo, a compreens?o de suas propriedades f?sico-qu?micas, tais como viscosidade, solubilidade e tamanho de part?culas em fun??o do pH e temperatura ainda ? muito limitada. Esta tese descreve sistemas de misturas f?sicas e copol?meros ? base de carboximetilcelulose e poli (Nisopropilacrilamida) (PNIPAM) com diferentes composi??es percentuais de alimenta??o reacional (25CMC, 50CMC e 75CMC), em solu??o aquosa. A estrutura qu?mica dos pol?meros foi investigada por infravermelho e an?lise elementar CHN. As misturas f?sicas foram analisadas por reologia e os copol?meros foram analisados por UV-vis?vel, espalhamento de raios-X a baixos ?ngulos (SAXS), espalhamento de luz din?mico (DLS) e potencial zeta. CMC e copol?mero foram avaliados como inibidores de incrusta??o de carbonato de c?lcio (CaCO3) usando os testes de compatibilidade qu?mica e precipita??o din?mica em capilar, assim como a microscopia eletr?nica de varredura (MEV). As misturas f?sicas 50% CMC_50% PNIPAM e 25% CMC_75% PNIPAM em solu??o aquosa, nas concentra??es de 6 e 2 g/L, respectivamente, apresentaram comportamento termoviscosificante dependente da concentra??o de pol?mero e da composi??o. Para os copol?meros, o aumento da quantidade de PNIPAM e da temperatura favoreceu as intera??es pol?mero-pol?mero atrav?s dos grupos hidrof?bicos, resultando no aumento da turbidez das solu??es polim?ricas. O tamanho das part?culas diminuiu com o aumento do teor de PNIPAM na composi??o dos copol?meros em fun??o do pH (3-12), a 25 ?C. Maiores quantidades de CMC resultaram em um efeito mais forte do pH nos tamanhos das part?culas, exibindo um comportamento pH-responsivo. Assim, 25CMC n?o foi afetada pela mudan?a de pH, apresentando comportamento similar a PNIPAM. Al?m disso, a presen?a de aditivos de car?ter ?cido ou b?sico influenciou no tamanho das part?culas, que foram menores na presen?a desses aditivos do que em ?gua destilada. Os resultados de potencial zeta tamb?m sofreram maior varia??o para os pol?meros em ?gua destilada do que na presen?a de ?cidos e bases. A temperatura consoluta inferior (LCST) da PNIPAM determinada por DLS foi concordante com o valor obtido por UV-visible. Os dados de SAXS mostraram para PNIPAM e 50CMC uma transi??o de fase quando a temperatura aumentou de 32 para 34 ?C. Um aumento do car?ter polieletrol?tico foi observado em fun??o do aumento da CMC na composi??o dos copol?meros. A avalia??o das amostras como inibidores de incrusta??o mostrou que a CMC apresenta um melhor desempenho do que o copol?mero. Isto foi atribu?do a maior densidade de cargas presente na CMC. As micrografias do MEV confirmaram mudan?as morfol?gicas dos cristais de CaCO3, indicando o potencial desses pol?meros para inibi??o de incrusta??o

This work describes three alternative processes for producing microfibrillated cellulose (MFC; also referred to as cellulose nanofibrils, CNF) in which bleached pulp fibres are first pretreated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated by a combined enzymatic and mechanical pretreatment. In the two other processes, cell wall delamination was facilitated by pretreatments that introduced anionically charged groups into the fibre wall, by means of either a carboxymethylation reaction or irreversibly attaching carboxymethylcellulose (CMC) to the fibres. All three processes are industrially feasible and enable energy-efficient production of MFC. Using these processes, MFC can be produced with an energy consumption of 500–2300 kWh/tonne. These materials have been characterized in various ways and it has been demonstrated that the produced MFCs are approximately 5–30 nm wide and up to several microns long. The MFCs were also evaluated in a number of applications in paper. The carboxymethylated MFC was used to prepare strong free-standing barrier films and to coat wood-containing papers to improve the surface strength and reduce the linting propensity of the papers. MFC, produced with an enzymatic pretreatment, was also produced at pilot scale and was studied in a pilot-scale paper making trial as a strength agent added at the wet-end for highly filled papers. / <p>QC 20150126</p>