Thesis (Ph. D.)--Institute of Paper Chemistry, 1956. / Includes bibliographical references (p. 110-113).

<p>The objectives of this work were (i) to develop a new methodfor the preparation of thin cellulose model films, (ii) to usethese model films for swelling measurements and (iii) to relatethe swelling of fibers and films to the dry strength ofpaper.</p><p>In the new film preparation method, NMMO(N-methylmorpholine-N-oxide) was used to dissolve cellulose andDMSO (dimethyl sulfoxide) was added to control the viscosity ofthe cellulose solution. A dilute solution of the cellulose wasspin-coated onto a silicon oxide wafer and the cellulose filmthus prepared was then precipitated in deionised water. Asaturated layer of glyoxalated-polyacrylamide was used toanchor the film onto the silicon oxide wafer. This proceduregave films with thicknesses in the range of 20-270 nm. Thefilms were cleaned in deionised water and were found by ESCAanalysis and contact angle measurements (θ<20°)to be free from solvents. Solid state NMR measurements onfibers spun from NMMO also indicated that the model filmconsisted of about 50% crystalline material and that thecrystalline structure was of the cellulose II type.Determination of the molecular weight distribution of thecellulose surface material showed that the NMMO treatmentcaused only a minor breakdown of the cellulose chains and thatlow molecular mass oligomers of glucose were not created.</p><p>It was further shown that atomic force microscopy (AFM)measurements could be used to determine the thicknessof thecellulose films, in both the dry and wet states. The thicknesswas determined as the height difference between the top surfaceand the underlying silica wafer measured at a position where anincision had been made in the cellulose film. The cellulosesolutions were also directly spin-coated onto the crystal usedin the Quartz crystal microbalance (QCM-D), pre-treated withthe same type of anchoring polymer. With this application,these model surfaces were shown to be suitable for swellingmeasurements with the QCM-D. The extent of swelling and theswelling kinetics in the presence of electrolytes, such asNaCl, CaCl2 and Na2SO4, and at different pH were measured inthis way. The films were found to be very stable during thesemeasurements and the results were comparable to the swellingresults obtained for the corresponding pulps. The swelling ofboth fibers and films followed the general behavior ofpolyelectrolyte gels in the presence of electrolytes and was inaccordance with the Donnan equilibrium theory. The films havebeen shown to differ from fibers with regard to the absence ofa covalent interior network. This influences the evaluation ofthe deswelling effects measured on the model films. Theswelling effect seen with different electrolytes has also beenconsidered in relation to the tensile strength of paperprepared from a kraftliner-pulp. In this study, it was foundthat there was no direct relationship between the swelling ofthe fibers, measured as WRV, and the strength of the paper inthe presence of different electrolytes at pH 5.</p><p><b>KEYWORDS:</b>absorption, carboxymethyl cellulose,cellulose, cellulose fibers, dissolving pulps, donnanequilibrium, electrolytes, film, ion exchange, ionization,kinetics, liner boards, microscopy, spinning, surfaces,swelling, tensile strength, water, water retention value.</p>

The objectives of this work were (i) to develop a new methodfor the preparation of thin cellulose model films, (ii) to usethese model films for swelling measurements and (iii) to relatethe swelling of fibers and films to the dry strength ofpaper. In the new film preparation method, NMMO(N-methylmorpholine-N-oxide) was used to dissolve cellulose andDMSO (dimethyl sulfoxide) was added to control the viscosity ofthe cellulose solution. A dilute solution of the cellulose wasspin-coated onto a silicon oxide wafer and the cellulose filmthus prepared was then precipitated in deionised water. Asaturated layer of glyoxalated-polyacrylamide was used toanchor the film onto the silicon oxide wafer. This proceduregave films with thicknesses in the range of 20-270 nm. Thefilms were cleaned in deionised water and were found by ESCAanalysis and contact angle measurements (θ&lt;20°)to be free from solvents. Solid state NMR measurements onfibers spun from NMMO also indicated that the model filmconsisted of about 50% crystalline material and that thecrystalline structure was of the cellulose II type.Determination of the molecular weight distribution of thecellulose surface material showed that the NMMO treatmentcaused only a minor breakdown of the cellulose chains and thatlow molecular mass oligomers of glucose were not created. It was further shown that atomic force microscopy (AFM)measurements could be used to determine the thicknessof thecellulose films, in both the dry and wet states. The thicknesswas determined as the height difference between the top surfaceand the underlying silica wafer measured at a position where anincision had been made in the cellulose film. The cellulosesolutions were also directly spin-coated onto the crystal usedin the Quartz crystal microbalance (QCM-D), pre-treated withthe same type of anchoring polymer. With this application,these model surfaces were shown to be suitable for swellingmeasurements with the QCM-D. The extent of swelling and theswelling kinetics in the presence of electrolytes, such asNaCl, CaCl2 and Na2SO4, and at different pH were measured inthis way. The films were found to be very stable during thesemeasurements and the results were comparable to the swellingresults obtained for the corresponding pulps. The swelling ofboth fibers and films followed the general behavior ofpolyelectrolyte gels in the presence of electrolytes and was inaccordance with the Donnan equilibrium theory. The films havebeen shown to differ from fibers with regard to the absence ofa covalent interior network. This influences the evaluation ofthe deswelling effects measured on the model films. Theswelling effect seen with different electrolytes has also beenconsidered in relation to the tensile strength of paperprepared from a kraftliner-pulp. In this study, it was foundthat there was no direct relationship between the swelling ofthe fibers, measured as WRV, and the strength of the paper inthe presence of different electrolytes at pH 5. KEYWORDS:absorption, carboxymethyl cellulose,cellulose, cellulose fibers, dissolving pulps, donnanequilibrium, electrolytes, film, ion exchange, ionization,kinetics, liner boards, microscopy, spinning, surfaces,swelling, tensile strength, water, water retention value. / <p>NR 20140805</p>

No description available.

3'-Carboxymethyl-3'-deoxyadenosine derivatives were prepared from 2'-O-TBDMS-3'-deoxy-3'-[(ethoxycarbonyl)methyl]adenosine (1) via simple and efficient procedures. Conversion of 1 to 5'-azido-2'-O-TBDMS-3', 5'-dideoxy -3'-[(ethoxycarbonyl) methyl] adenosine (4) was accomplished via a novel one-pot method employing 5'-activation (TosCl) followed by efficient nucleophilic displacement with tetramethylguanidinium azide. Compound 4 was converted to a 5'-[(N-methylcarbamoyl)amino] derivative (5) via one-pot reduction/acylation employing H2/Pd-C followed by treatment with p-nitrophenyl N-methylcarbamate. The latter step of this two-step process required an efficient source of p-nitrophenyl N-methylcarbamate, thus a highly efficient new method for preparing p-nitrophenyl N-alkylcarbamate was developed. N6-phenylcarbamoyl groups were introduced by treatment with phenylisocyanate, and an efficient new method for lactonization of 2'-O-TBDMS-3'-deoxy-3'-[(ethoxycarbonyl)methyl]adenosines to give corresponding 2', 3'-lactones was also developed. Target compounds were evaluated for anti-HIV and anti-HIV integrase activities, but were not active at the concentrations tested.

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. / This experimental work is a contribution to the study of rheological and pipe flow proprieties of complex fluids (yield stress and thixotropic). Bentonite suspensions and mixtures containing bentonite and carboxymethyl cellulose were investigated. The axial velocity distribution was determined using ultrasonic pulsed Doppler velocimetry technique. In the first experimental part of the thesis, rheological and pipe flow measurements were performed for pure bentonite suspensions at different concentrations. A detailed study is presented on the evolution of the friction factors and velocity profiles for different flow regimes. In a second part, suspension of bentonite and mixtures of bentonite / CMC at different mass concentrations of polymer were studied in terms of their rheological and hydrodynamic flow behavior. It was shown that the polymer has viscosifying properties in laminar regime. However, in the turbulent regime, the polymer acts as a friction reducer. The last part of the thesis was devoted to the study of the effect of temperature on the rheological behavior of polymer solutions and mixtures of clay / polymer. The rheological measurements at different temperatures showed a thermodependent character of the different fluids.

O amido, encontrado abundantemente na natureza, é formado por dois polímeros: a amilopectina e a amilose. Ambos polímeros possuem excelentes qualidades industriais tais como, a biodegradabilidade e o baixo custo de obtenção. Entretanto, a amilopectina possui baixa solubilidade em solução aquosa. Para expandir a gama de aplicações deste polímero como, por exemplo, a produção de filmes biodegradáveis solúveis em água e que possam ser usados como revestimento de proteção no transporte de alimentos, ainda se fazem necessários alguns estudos. Um deles é tentar correlacionar como a funcionalização do seu esqueleto polimérico pode afetar a reação de formação destes filmes. Neste sentido, o objetivo desta Dissertação de Mestrado foi estudar a síntese da carboximetil amilopectina (CMAm) variando-se a pressão, temperatura e razão entre água e solvente orgânico. Sintetizamos várias CMAm a partir da amilopectina de milho ceroso, por meio de uma reação heterogênea utilizando hidróxido de sódio e ácido cloroacético. Empregou-se uma mistura de dimetilsulfóxido (DMSO) e água como solvente, com uma proporção variável entre 0 a 50% de água, para as pressões ambiente (758,3 mmHg) e reduzida (80 ± 20 mmHg) e para as temperaturas 70 e 80 ºC. Para cada uma das condições sintéticas estudadas, obtivemos CMAm com graus de substituição (GS) diversos. Os GS foram determinados por titulações condutimétricas com hidróxido de amónio e para as amostras sintetizadas com 0 a 40% de água foram confirmados por cromatografia líquida de alta eficiência (HPLC), obtendo-se uma boa correlação entre estes valores (R2 de 0,94263). Atribuiu-se os picos referentes às estruturas monossubstituídas (2-; 3- ou 6-mono-O-carboximetil glicose), dissubstituídas (2,3-; 2,6- ou 3,6-di-O carboximetil glicose) e trissubstituídas (2,3,6-tri-O-carboximetil glicose) por meio da cromatografia líquida acoplada a espectrometria de massa (LC-MS). A síntese realizada a 70 oC, pressão reduzida apresenta uma distribuição de CMAm substituída mais homogênea do que as demais condições sintéticas estudadas. Por medidas de potencial zeta em função do pH, determinaram-se para as CMAm de GS 0,86 e 0,43 o ponto isoelétrico no pH de 3,6 e 4,6; respectivamente. O espalhamento dinâmico de luz mostrou que a funcionalização da amilopectina com grupos carboximetílicos levou a abertura da sua estrutura inicial, extremamente ramificada, permitindo a formação de agregados maiores em solução aquosa para as amostras sintetizadas a 80 ºC sob pressão reduzida. Em contraste, as sínteses a 70 ºC nas pressões ambiente e reduzida provocaram uma diminuição no tamanho dos agregados em solução aquosa em função do GS. Por fim, a análise por microscopia ótica e eletrônica de varredura dos filmes de CMAm sintetizadas neste trabalho mostraram que são totalmente dependentes do GS, tipo de substituinte e o tamanho dos agregados em solução aquosa. / Starch is abundant in nature and composed by two polymers: amylopectin and amylose. Both biopolymers have excellent industrial characteristics, such as biodegradability and low cost. However, amylopectin has a very low solubility in aqueous solution. In order to expand the uses this biopolymer, for instance, the production of aqueous soluble and biodegradable films for food packing, there are still many open fields to study. One of them is to find the correlation between how the functionalization of the polymer backbone can affect the film formation process. For this reason, the goal of this work was to study the synthesis of carboxymethyl amylopectin (CMAm) varying the employed pressure, temperature and the ratio of water and organic solvent. Several CMAm were synthetized using amylopectin from maize, by means of an heterogeneous reaction using sodium hydroxide and chloroacetic acid. We have used a mixture of dimethyl sulfoxide (DMSO) and water as reaction solvent with variable ratio of 0 to 50% of water, employed ambient (758,3 mmHg) or reduced (80 ± 20 mmHg) pressure and temperatures of 70 and 80 ºC. The degree of substitution (DS) were determined for every synthetic condition studied in this work. The DS were determined through conductometric titration with ammonium hydroxide. The DS of the samples synthesized with 0 to 40% of water, were confirmed by high performance liquid chromatography (HPLC), with good correlation between these values (R2 of 0,94263). The peaks of the monosubstituted structures (2-; 3- ou 6-mono-O-carboxymethyl glucose), disubstituted (2,3-; 2,6- ou 3,6-di-O carboxymethyl glucose) e trisubstituted (2,3,6-tri-Ocarboxymethyl glucose) were attributed by liquid chromatography coupled with mass spectrometry (LC-MS). The synthesis made at 70 oC, reduced pressure, showed a more even distribution of substituted CMAm than the other synthetic conditions analyzed in this work. The isoelectric point of CMAm of DS of 0.86 and 0.43 were determined by zeta potential as function of pH. They were, respectively of pH 3.6 and 4.6. The dynamic light scattering showed that the funcionalization of the amylopectin with carboxymethyl groups has opened the initial branched polymer backbone, for samples synthesized at 80 ºC under reduced pressure, forming large aggregates in aqueous solution. On the other hand, the synthesis at 70 ºC at ambient and reduced pressures has caused a reduction of the aggregates sizes in aqueous solution as function of increasing DS. The optic and electronic scan microscopies of the CMAm films showed that they are completely dependent on DS, sort of susbstituents and sizes of the aggregates in aqueous solution.

Les produits de glycation avancée (AGEs) sont trouvés en excès dans le plasma et les tissus au cours du diabète, de l'insuffisance rénale et du vieillissement. Ils se forment aussi pendant la cuisson domestique et industrielle des aliments. Actuellement, la plus forte consommation de denrées alimentaires transformées contenant des quantités importantes des AGEs augmente le risque d'exposition de la population aux AGEs et à leurs effets biologiques. C'est ainsi que l'étude de la biodisponibilité des AGEs devient un sujet d'actualité dans la compréhension de la pathogenèse de certaines maladies chroniques, particulièrement le diabète. Deux études cliniques ont été menées dans le but d'étudier l'impact de l'ingestion des AGEs alimentaires sur les fluctuations des concentrations de ces mêmes molécules retrouvées dans les fluides biologiques des individus sains étudiés. Une première étude qui compare la teneur des AGEs ingérés à travers deux régimes alimentaires administré à 62 jeunes adultes. Une deuxième étude qui évalue la teneur en AGEs d'une alimentation basée sur du lait maternel ou du lait de formules infantiles donné à 161 bébés. La quantification de la carboxyméthyllysine (CML) et des AGEs fluorescents comme indicateurs de la réaction de Maillard a été effectuée dans les aliments administrés aux sujets de l'étude ainsi que dans leurs matrices biologiques : plasma, urine et fèces. Les résultats montrent qu'un régime contenant 2,5 fois moins de CML et 1,7 fois moins des AGEs fluorescents, en comparaison avec un régime courant ou standard, peut provoquer des baisses importantes de ces indicateurs dans le plasma, l'urine et la matière fécale des individus sains. Ces diminutions sont plus accentuées au niveau de l'excrétion urinaire. D'autre part, une plus forte présence de la CML dans le lait de formules infantiles correspond à une plus forte quantité de CML dans le plasma et dans l'urine des enfants ayant ingéré cet aliment, à la différence des enfants nourris avec le lait maternel, caractérisé par de faibles quantités de la CML. Chez les adultes soumis au régime bas en AGEs ainsi que les bébés nourris avec le lait maternel, les niveaux de certains paramètres métaboliques tels que le stress oxydatif, les antioxydants importants et des facteurs de l'inflammation cellulaire et systémique ont été normaux mais inférieurs à ceux des adultes et des enfants ayant ingéré de plus fortes quantités d'AGEs. Ces effets indiquent que de plus faibles quantités de produits de Maillard alimentaires pourraient avoir un impact sur la prévention des maladies chroniques. / Advanced Glycation End Products (AGEs) are found in excess in plasma and tissus during diabetes, renal diseases and aging. AGEs are known to form in foods during industrial processes or home cooking. Nowadays, an excessive intake of technologically transformed foods riches in AGEs, increase the risk of the population to their possible pathophysiological effects. In this contexte, the study of bioavailability of AGEs formed in foods may have a significant impact in understanding the pathogenesis of some chronic diseases as diabetes.Two clinical studies were conducted to study the impact of dietary intake of AGEs on fluctuating levels of these same molecules found in biological fluids of healthy individuals studied. A first study that compared the content of AGEs ingested through two diets administered to 62 young adults. A second study evaluates the AGE content of a diet based on breast milk or infant formula milk given to 161 babies. Quantification of CML and fluorescent AGEs as indicators of the Maillard reaction was performed in the food administered to the subjects and their biological matrices: plasma, urine and feces. The results show that a diet containing less than 2.5 times and 1.7 times of CML and fluorescent AGEs respectively, compared with a current or standard diet, can cause significant declines in these indicators in plasma, urine and fecal matter of healthy individuals. These decreases are more pronounced at the level of urinary excretion. A stronger presence of CML in the milk of infant formula is a higher amount of CML in plasma and urine of children who ingested this food, unlike the children fed with milk breast, characterized by low levels of CML. In adults subjected to diet low in AGEs and babies fed breast milk, the levels of some metabolic parameters such as oxidative stress, antioxidants and important factors of cellular and systemic inflammation, were lower than normal levels of adults and children who ingested higher amounts of AGEs. These effects indicate that lower amounts of dietary Maillard products could have an impact on chronic disease prevention

Carboxymethyl cellulose (CMC) is produced commercially in a two-stage process consisting of a mercerization stage, where the pulp is treated with alkali in a water alcohol solution, followed by an etherification stage in which monochloroacetic acid is added to the pulp slurry. In this thesis an extended mercerization stage of a spruce ether pulp was investigated where the parameters studied were the ratio of cellulose I and II, concentration of alkali, temperature and retention time. The influence of the mercerization stage conditions on the etherification stage, were evaluated as the degree of substitution (DS) of the resulting CMC and the filterability of CMC dissolved in water at a concentration of 1%. The DS results suggested that the NaOH concentration in the mercerization stage was the most important of the parameters studied. When the NaOH concentration in the mercerization step was low (9%), a high cellulose II content in the pulp used was found to have no negative impact on the DS of the resulting CMC compared with pulps with only cellulose I. However, when the NaOH concentration was high (27.5%), pulps with high content of cellulose II showed a lower reactivity than those with only cellulose I with respect to the DS of the CMC obtained after a given charge of NaMCA. The results obtained from the filtration ability study of CMC water solutions suggested that both the amount of cellulose II in the original pulp and the temperature had a negative influence on the filtration ability whereas the NaOH concentration in the mercerization stage had a positive influence. The filtration ability was assumed to be influenced highly by the presence of poorly reacted cellulose segments. A retention time between 1-48 h in the mercerization stage had no effect on either the DS or the filtration ability of the CMC. Using NIR FT Raman spectroscopy molecular structures of CMC and its gel fraction were analyzed with respect to the conditions used in the extended mercerization stage. Here it was found that the alkaline concentration had a very strong influence on the following etherification reaction. FT Raman spectra of CMC samples and their gel fractions prepared with low NaOH concentrations (9%) in the mercerization stage indicated an incomplete transformation of cellulose to Na-cellulose before carboxymethylation to CMC. Low average DS values of the CMC, i.e. between 0.42 and 0.50, were yielded. Such CMC dissolved in water caused very thick and semi solid gum-like gels, probably due to an uneven distribution of substituting groups along the cellulose backbone. FT Raman spectra of CMC mercerized with alkaline concentrations at 18.25 and 27.5% in the mercerization stage indicated, however, that all of the cellulose molecules were totally transferred to CMC of high DS, i.e. between 0.88 and 1.05. When dissolved in water such CMC caused gels when they were prepared from ether pulp with a high fraction of cellulose II.

Cellulose is one of the most abundant biopolymers found in nature. Cellulose based derivatives have a number of advantages including recyclability, reproducibility, biocompatibility, biodegradability, cost effectiveness and availability in a wide variety of forms. Due to the benefits of cellulose based systems, this research study was aimed at developing novel cellulosic nanoparticles with potential pharmaceutical and personal care applications. Two different cellulosic systems were evaluated, each with its own benefits and proposed applications. The first project involves the synthesis and characterization of polyampholyte nanoparticles composed of chitosan and carboxymethyl cellulose (CMC), a cellulosic ether. EDC carbodiimide chemistry and inverse microemulsion technique was used to produce crosslinked nanoparticles. Chitosan and carboxymethyl cellulose provide amine and carboxylic acid functionality to the nanoparticles thereby making them pH responsive. Chitosan and carboxymethyl cellulose also make the nanoparticles biodegradable and biocompatible, making them suitable candidates for pharmaceutical applications. The synthesis was then extended to chitosan and modified methyl cellulose microgel system. The prime reason for using methyl cellulose was to introduce thermo-responsive characteristics to the microgel system. Methyl cellulose was modified by carboxymethylation to introduce carboxylic acid functionality, and the chitosan-modified methyl cellulose microgel system was found to be pH as well as temperature responsive. Several techniques were used to characterize the two microgel systems, for e.g. potentiometric and conductometric titrations, dynamic light scattering and zeta potential measurements. FTIR along with potentiometric and conductometric titration was used to confirm the carboxymethylation of methyl cellulose. For both systems, polyampholytic behaviour was observed in a pH range of 4-9. The microgels showed swelling at low and high pH values and deswelling at isoelectric point (IEP). Zeta potential values confirmed the presence of positive charges on the microgel at low pH, negative charges at high pH and neutral charge at the IEP. For chitosan-modified methyl cellulose microgel system, temperature dependent behaviour was observed with dynamic light scattering. The second research project involved the study of binding interaction between nanocrystalline cellulose (NCC) and an oppositely charged surfactant tetradecyl trimethyl ammonium bromide (TTAB). NCC is a crystalline form of cellulose obtained from natural sources like wood, cotton or animal sources. These rodlike nanocrystals prepared by acid hydrolysis of native cellulose possess negatively charged surface. The interaction between negatively charged NCC and cationic TTAB surfactant was examined and it was observed that in the presence of TTAB, aqueous suspensions of NCC became unstable and phase separated. A study of this kind is imperative since NCC suspensions are proposed to be used in personal care applications (such as shampoos and conditioners) which also consist of surfactant formulations. Therefore, NCC suspensions would not be useful for applications that employ an oppositely charged surfactant. In order to prevent destabilization, poly (ethylene glycol) methacrylate (PEGMA) chains were grafted on the NCC surface to prevent the phase separation in presence of a cationic surfactant. Grafting was carried out using the free radical approach. The NCC-TTAB polymer surfactant interactions were studied via isothermal titration calorimetry (ITC), surface tensiometry, conductivity measurements, phase separation and zeta potential measurements. The major forces involve in these systems are electrostatic and hydrophobic interactions. ITC and surface tension results confirmed two kinds of interactions: (i) electrostatically driven NCC-TTAB complexes formed in the bulk and at the interface and (ii) hydrophobically driven TTAB micellization on the NCC rods. Conductivity and surface tension results confirmed that the critical micelle concentration of TTAB (CMCTTAB) shifted to higher values in the presence of NCC. Phase separation measurements allowed us to identify the formation of large aggregates or hydrophobic flocs depending on the TTAB concentration. Formation of NCC-TTAB complexes in aqueous solutions was confirmed by a charge reversal from negative to positive charge on the NCC rods. The effect of electrolyte in shielding the negative charges on the NCC was observed from ITC, surface tensiometry and phase separation experiments. Several mechanisms have been proposed to explain the above results. Grafting of PEGMA on the NCC surface was confirmed using FTIR and ITC experiments. In phase separation experiments NCC-g-PEGMA samples showed greater stability in the presence of TTAB compared to unmodified NCC. By comparing ITC and phase separation results, an optimum grafting ratio (PEGMA : NCC) for steric stabilization was also proposed.