L’évolution des propriétés d’adhérence dépend de la nature de l’adhésion entre le mortier et son support, mais également des conditions environnementales auxquelles l’ouvrage est exposé. Les mortiers de façade sont intrinsèquement soumis au séchage. Ce phénomène tend a priori à réduire la résistance du lien entre les matériaux par la limitation du développement de l’adhésion et par la création de contraintes de traction et de cisaillement.Ces dernières peuvent conduire à la fissuration voire à la désolidarisation du mortier.L’objectif de cette thèse est de comprendre les phénomènes initiateurs de cette fissuration et d’évaluer son impact sur l’adhérence. Le couplage entre hydratation et séchage, le dosage en éther de cellulose et la rugosité du support sont les principaux paramètres étudiés. Les dispositifs expérimentaux développés au cours de ces travaux mises en place révèlent que ces trois paramètres influencent significativement la fissuration des mortiers. Aucun lien clair n’a cependant pu être mis en évidence entre fissuration et adhérence. / The quality of adherence between a coating mortar and its substrate, such as building front wall, depends on environmental conditions. Especially, the restraint of the drying shrinkage of the mortar by the substrate usually results in tensile stresses. This could lead to cracking or even debonding. The main objective of the present PhD dissertation is to study the cracking phenomenon due to restrained drying shrinkage and its impact on the failure of the mortar/substrate system. The interaction between cement hydration and drying, the content of cellulose ether (used as chemical admixture) and the substrate roughness are the main studied parameters. For this purpose, several original experimental devices were developed. In particular, cracking was investigated with digital image correlation. The three studied parameters appeared to influence significantly the adherence and cracking. However, no clear relation between cracking and adherence could be emphasized.

The aim of this diploma work was to execute surface treatment of non-ionic cellulose ethers EHEC that AkzoNobel provides under the tradename Bermocoll®. In order for the cellulose ether to dissolve without forming lumps, some surface treatment is commonly required. In this work glyoxal has been used for this surface modification using two different lab-scale methods that in different ways mimic the full scale production. It is an everlasting challenge for the chemical industry to reduce the consumption of chemicals and also reduce energy consumption in the production. Therefore one objective of this work was to gain fundamental understanding about the glyoxal reaction with EHEC in terms of required equivalents glyoxal, reaction temperature and reaction time. Another aim of this work was to compare the two lab scale methods with regards to their predictivity and reproducibility of results.One method is called the dry method in which a water solution of glyoxal was added to dry, non-glyoxal treated EHEC at varying temperature during heavy agitation. The second method is called the acetone method where the EHEC and glyoxal were first suspended in acetone at room temperature, and then heated at different temperature for various time periods. The parameters in the experiments made was chosen using a design of experiments (DoE) approach in order to gain as much information as possible from a few experiments and also facilitating a statistical analysis of the results.This diploma work indicates that the acetone method have a better reproducibility and would be the better choice when investigating various parameters for the reaction. On the other hand the dry method might be better suited for the further analysis of temperature dependence of the glyoxal reaction with cellulose ethers. The most important factor for the reaction was the amount of glyoxal used, whereas it is indicated that the reaction temperature had a minor effect on the reaction yields. / Program: Högskoleingenjörsexamen i Kemiingenjör – tillämpad bioteknik

Today’s market offers an ever-increasing range of cellulose pulps (derivative pulps) made fromvarious wood types through different delignification processes. Each pulp segment has its uniquecharacteristics, which makes it difficult for the producer of cellulose derivatives to choose the mostsuitable pulp for optimum processability and product quality. The objective of this study was toimprove knowledge of cellulose pulps and to describe how different pulp properties affectprocessability and quality in the production of viscose dope and cellulose ethers.Ten pulp samples were investigated, originating from both sulfite and sulfate processes, with highand low viscosities and with softwood and hardwood as raw material. The pulps were analyzed fortheir properties and then processed to viscose dope and a cellulose ether in two separate pilotfacilities. The intermediates in the viscose process as well as the quality of the viscose dope andcellulose ether were analyzed and the results correlated to pulp properties.Multivariate regression methods were applied to investigate the dominating physical and chemicalproperties of each pulp and pulp segment, and to study the use of spectroscopic analyses inpredicting pulp origin, concentration and composition of hemicelluloses as well as the content ofreducing end groups in cellulose. For the production of viscose dope, the models presented showedthe most important pulp properties for good cellulose reactivity and viscose filterability. In addition,the properties affecting gel formation, flocculation, degree of substitution and clarity in theproduction of cellulose ether were highlighted. The study also emphasized the need to supplementthe use of conventional analyses on pulps and viscose intermediates with other analytical methods,such as molecular weight distribution and carbohydrate analysis, to better predict the quality ofboth viscose dope and viscose fiber.The results of the present study could be useful to predict the origin and properties of new pulps, toreplace or supplement otherwise expensive pulp analyses, and to assess the impact of pulpproperties on the production of cellulose derivatives without extensive pilot-scale trials.

Polysaccharides are known as among the most abundant natural polymers on the Earth. As this class of material is usually renewable, biodegradable, biocompatible in many contexts and environmentally friendly, it is of great interest to use these benign polymers to design and prepare materials, especially for applications with green and biomedical purposes. In this dissertation we will discuss novel pathways to two different types of polysaccharide-based materials: block copolymers and hydrogels. Block copolymers are composed of two or even more covalent bonded polymer blocks that have quite distinct properties. Synthesis of polysaccharide-based block copolymers is an attractive and challenging research topic, opening up promising application potential and requiring advances in polysaccharide regio- and chemoselectivity. Herein, we report two independent approaches to prepare these interesting and potential useful materials. In one approach, trimethyl cellulose was modified regiospecifically at the reducing end anomeric carbon to create an ω-unsaturated alkyl acetal by solvolysis with an ω-unsaturated alcohol. Then, olefin cross-metathesis, a known versatile and mild tool for polysaccharide chemical modification, was used to couple the trimethyl cellulose block with various polymer blocks containing acrylates. To demonstrate the method, trimethyl cellulose-b-poly(tetrahydrofuran), cellulose-b-poly(ethylene glycol), and cellulose-b-poly(lactic acid) were synthesized by this coupling strategy. In another approach, we introduced a simple and novel method to prepare dextran-based block copolymers. In this strategy, N-bromosuccinimide (NBS)/triphenyl phosphine (PPh3) was chosen to regioselectively brominate the only primary alcohol of linear unbranched dextran. The resulting dextran, bearing a terminal C-6 bromide, was coupled with several amine terminated polymers via SN2 substitution to obtain block copolymers, including dextran-b-polystyrene, dextran-b-poly(N-isopropylacrylamide) and dextran-b-poly(ethylene glycol). Dextran-b-poly(N-isopropylacrylamide) exhibits thermally-induced micellization as revealed by dynamic light scattering, forming micelles with 155 nm diameter at 40 °C. Dextran-b-polystyrene film was analyzed by small angle X-ray scattering, suggesting the existence of microphase separation. This dissertation also introduces a novel, simple and effective strategy to prepare polysaccharide-based hydrogels. Hydrogels are typically crosslinked hydrophilic polymers that have high water affinity and no longer dissolve in water. Polysaccharide-based hydrogels are of great interest to for biomedical applications due to their benefits including biocompatibility, polyfunctionality, and biodegradability. Recently the Edgar group has discovered that chemoselective oxidation of oligo(hydroxypropyl)-substituted polysaccharides impairs ketone groups at the termini of the oligo(hydroxypropyl) side chains. These ketones can condense with amines to form imines, leading hydrogel formation., Based on this concept, we prepared oxidized hydroxypropyl polysaccharide/chitosan hydrogels. This class of all-polysaccharide hydrogels exhibits a series of interesting properties such as tunable moduli (300 Pa to 13 kPa), self-healing, injectability, and high swelling ratios. To further explore imine-crosslinked hydrogels, we designed thermally responsive hydrogels by using a Jeffamine, a polyethylene oxide-b-polypropylene oxide-b-polyethylene oxide triblock copolymer with two terminal amines. As the Jeffamine has a lower critical solution temperature, oxidized hydroxypropyl cellulose/Jeffamine hydrogels display moduli that are tunable by controlling the temperature. / Doctor of Philosophy / Polysaccharide are natural polymers that are among the most abundant polymers on Earth. It is greatly in society's interest to extend the scope of their applications, due to the benign nature of polysaccharides. This dissertation mainly focuses on two polysaccharides: cellulose and dextran. Cellulose is a long linear polymer of linked glucose molecules. As cellulose is sustainable, biodegradable, non-toxic, affordable and accessable for chemical modification, it is a suitable polymer for biomedical and environmentally friendly application. Dextran is also a polymer chain made up only of glucose but connected with each other differently from cellulose by, bacterial fermentation, and it may be lightly branched. It is biocompatible in many situations and is biodegradable both in vivo and in the environment, thus it has been investigated for drug delivery and many other medical applications. Using these two polysaccharides, we designed and prepared two quite different classes of materials: block copolymers and hydrogels. Block copolymers consist of two or more different types of polymer blocks connected by strong covalent bonds. As block copolymerization enables construction of a single polymer comprising segments with distinct properties, it is appealing to synthesize a block copolymer which preserves the properties of natural polymers coupled to very different polymers, such as polyolefins (e.g. the polyethylene that is used for milk bottles). In order to prepare polysaccharide-based block copolymers, we developed two different synthetic routes to end-functionalize methyl cellulose and dextran , and these resulting products were used to prepare two independent series of polysaccharide-based block copolymers via combination (in other words, sticking the polysaccharide and, e.g., the polyethylene together end to end). This study confirms the feasibility of this method to make methyl cellulose-based and dextran-based block copolymers. We expect these classes of materials will have significant potential in applications including drug delivery, as compatibilizers for polymer blends of materials that otherwise cannot be mixed (polyolefin/polysaccharide), membrane and adhesive. Hydrogels are crosslinked polymer networks with high water affinity, and they have been heavily investigated in the field of tissue engineering, drug delivery, agriculture and 3D printing. Polysaccharide-based hydrogels are attractive materials for these applications because they are biocompatible, biodegradable and have polyfunctionality. However, any use of toxic small molecules to crosslink the hydrogels diminishes their usefulness in biomedical applications. In this work, we demonstrate a simple, green and efficient method for preparation of all-polysaccharide-based hydrogels. The starting materials, oxidized hydroxypropylpolysaccharide, were simply prepared by using household bleach (NaOCl) as the oxidation reagent. We discovered that oxidized hydroxypropyl polysaccharides readily form hydrogels with hydrophilic amine-containing polymers like chitosan (a natural polysaccharide that comes from shells of crustaceans like crabs or shrimp) and Jeffamines, affording interesting properties including tunable stiffness, self-healing, injectability, and responsiveness to acidity and temperature. We expect that this new class of hydrogel will be very promising for biomedical-related applications.

Amorphous solid dispersion (ASD) is a popular method to increase drug solubility and consequently poor drug bioavailability. Cellulose ω-carboxyesters were designed and synthesized specifically for ASD preparations in Edgar lab that can meet the ASD expectations such as high Tg, recrystallization prevention and pH-triggered release due to the free -COOH groups. Rifampicin (Rif), Ritonavir (Rit), Efavirenz (Efa), Etravirine (Etra) and Quercetin (Que) cellulose ester ASDs were investigated in order to increase drug solubility, prevent release at low pH and controlled release of the drug at small intestine pH that can improve drug bioavailability, decrease needed drug content and medication price to make it affordable in third world countries, and extent pill efficiency period to improve patient quality of life and adherence to the treatment schedule. The studies were compared with cellulose based commercial polymers to prove the impact of the investigation and potential for the application. Furthermore, the in vitro results obtained were further supported by in vivo studies to prove the significant increase in bioavailability and show the extended release. The need of new cellulose derivatives for ASD applications extended the research area, the design and synthesis of a new class of polymers, alkyl cellulose ω-carboxyesters for ASD formulations investigated and the efficiency of the polymers were summarized to show that they have the anticipated properties. The polymers were synthesized by the reaction of commercial cellulose alkyl ethers with benzyl ester protected, monofunctional hydrocarbon chain acid chlorides, followed by removal of protecting group using palladium hydroxide catalyzed hydrogenolysis to form the alkyl cellulose wcarboxyalkanoate. Having been tested for ASD preparation, it was proven that the polymers were efficient in maintaining the drug in amorphous solid state, release the drug at neutral pH and prevent the recrystallization for hours, as predicted. / Ph. D.

<p>Cellulose ethers and polyethylene glycols are used in drug formulations as water swelling or water soluble matrices. Polar lipids, for example monoglycerides, and surfactants can be used to solubilise hydrophobic or amphiphilic drugs and to formulate potential drug delivery vehicles such as emulsions, liposomes and cubic phases. In this thesis mixtures of these excipients are characterised in various environments, from dilute aqueous solutions to solid dispersions. Special focus has been on the understanding of the associating processes involved.</p><p>Detailed understanding of the association of cellulose ethers, of varying hydrophobicity, and amphiphilic substances is presented. The hydrophobicity of the polymer was found to have an impact on the interaction scheme. The amphiphiles were found to bind at lower amphiphile concentrations to a more hydrophobic polymer thus influencing both micro- and macroscopic structure of the aggregates. </p><p>The choice of counterion to the amphiphile has a small but significant effect on the interaction and the structure of the aggregates. Also amphiphilic drug molecules can interact with nonionic polymers in a similar way as surfactants in aqueous solution. Due to the higher cmc of the drug ibuprofen the interaction is largely influenced by the ionic strength of the solution. The type of amphiphile also influences the cooperativity of the amphiphile-polymer binding.</p><p>In more concentrated systems liquid crystals are formed into which the polymer interact with the amphiphiles. Both cubic and sponge phases were found with relatively large polymers interacting with polar lipids. These phases were found to swell and shrink mainly controlled by the amount of polymer inside them. Also membrane interacting substances added to the sponge phase could influence the size of the water channels in the phase. </p><p>In water free systems polymers and polar lipids were found to interact as well as forming solid dispersions. The behaviour of the phase separation between polymer and lipid depended on the concentration of the dispersed phase. The polar lipid was found to be distributed in the lamellar part of the semicrystalline polymer influencing the polymer folding.</p>

Cellulose ethers and polyethylene glycols are used in drug formulations as water swelling or water soluble matrices. Polar lipids, for example monoglycerides, and surfactants can be used to solubilise hydrophobic or amphiphilic drugs and to formulate potential drug delivery vehicles such as emulsions, liposomes and cubic phases. In this thesis mixtures of these excipients are characterised in various environments, from dilute aqueous solutions to solid dispersions. Special focus has been on the understanding of the associating processes involved. Detailed understanding of the association of cellulose ethers, of varying hydrophobicity, and amphiphilic substances is presented. The hydrophobicity of the polymer was found to have an impact on the interaction scheme. The amphiphiles were found to bind at lower amphiphile concentrations to a more hydrophobic polymer thus influencing both micro- and macroscopic structure of the aggregates. The choice of counterion to the amphiphile has a small but significant effect on the interaction and the structure of the aggregates. Also amphiphilic drug molecules can interact with nonionic polymers in a similar way as surfactants in aqueous solution. Due to the higher cmc of the drug ibuprofen the interaction is largely influenced by the ionic strength of the solution. The type of amphiphile also influences the cooperativity of the amphiphile-polymer binding. In more concentrated systems liquid crystals are formed into which the polymer interact with the amphiphiles. Both cubic and sponge phases were found with relatively large polymers interacting with polar lipids. These phases were found to swell and shrink mainly controlled by the amount of polymer inside them. Also membrane interacting substances added to the sponge phase could influence the size of the water channels in the phase. In water free systems polymers and polar lipids were found to interact as well as forming solid dispersions. The behaviour of the phase separation between polymer and lipid depended on the concentration of the dispersed phase. The polar lipid was found to be distributed in the lamellar part of the semicrystalline polymer influencing the polymer folding.

The subject of this diploma thesis is a study of the influence of cellulose ethers on the rheological properties of lime. The theoretical part focuses on rheological parameters, techniques and test equipment used in rheology measurements. Various types of cellulose ethers and their influence on the rheological properties of fresh mortars are described. The practical part deals with the study of the influence of different types and quantities of cellulose ethers on the properties of fresh lime pastes and mortars. The results were obtained from measurements on a rotational rheometer with a special geometry for building materials. Measuring methods used were flow and oscillatory tests. Yield stress, viscosity and flow index were determined by the flow measurement. The stability and stiffness of fresh materials were determined during the oscillation measurements. The measured results are then evaluated and compared.