<p>The aim of the project was to modify polydimethylsiloxane (PDMS) surfaces in order to minimize adsorption of proteins. PDMS is used in micro-fluidic devices that control the delivery of samples to a sensor chip in Biacore instrumentation. These instruments are used to characterize interactions between biomolecules with a detection principle based on surface plasmon resonance (SPR). To minimize adsorption of proteins poly-ethylene-oxide (PEO) based surfactants, were added to the buffer. The added PEO surfactants were P20, Pluronic F-127 and Brij 35. Interaction of these surfactants with the sensor chip in Biacore instruments was also examined. Creating a more hydrophilic surface layer on PDMS by oxidation was also examined.</p><p>When surfactants were continuously added to protein samples, as in dynamically coating of PDMS surfaces, Brij 35 resulted in the strongest reduction in protein adsorption. Brij 35 was also the surfactant that was easiest to remove from both PDMS and the sensor surfaces. Pluronic bound strongest to surfaces, and is most suitable when only adding surfactant to the buffer in a pre-coating step. All surfactants did reduce protein adsorption considerably (99% or more) and addition is necessary when working with protein solutions and hydrophobic surfaces as PDMS. Another alternative is oxidation of PDMS surface, which is an easy procedure that decreased the protein adsorption to about 10% compared to adsorption to untreated surface.</p>

The aim of the project was to modify polydimethylsiloxane (PDMS) surfaces in order to minimize adsorption of proteins. PDMS is used in micro-fluidic devices that control the delivery of samples to a sensor chip in Biacore instrumentation. These instruments are used to characterize interactions between biomolecules with a detection principle based on surface plasmon resonance (SPR). To minimize adsorption of proteins poly-ethylene-oxide (PEO) based surfactants, were added to the buffer. The added PEO surfactants were P20, Pluronic F-127 and Brij 35. Interaction of these surfactants with the sensor chip in Biacore instruments was also examined. Creating a more hydrophilic surface layer on PDMS by oxidation was also examined. When surfactants were continuously added to protein samples, as in dynamically coating of PDMS surfaces, Brij 35 resulted in the strongest reduction in protein adsorption. Brij 35 was also the surfactant that was easiest to remove from both PDMS and the sensor surfaces. Pluronic bound strongest to surfaces, and is most suitable when only adding surfactant to the buffer in a pre-coating step. All surfactants did reduce protein adsorption considerably (99% or more) and addition is necessary when working with protein solutions and hydrophobic surfaces as PDMS. Another alternative is oxidation of PDMS surface, which is an easy procedure that decreased the protein adsorption to about 10% compared to adsorption to untreated surface.

<p>The varieties of paint are today very big, but many of the more popular paints are less than environmental friendly. The uses of fossilized fuel in paints are common because these paints dry fast and are color true. It would be beneficial for the environment if more renewable source were used to produce paint. Linseed oil is an old base for oil paints. It is renewable and easily procured. But linseed oils have some aspects that give it a bad reputation. There are problems with the slow drying and the color turning yellow when exposed to darkness for long periods of time. Researchers at KTH have connected the yellowing to linolenic acid, one of the common fatty acids in linseed oil (Svensson, M. Johansson, M, Stenberg, C. Samuelsson, J. 2003). Hempseed oil is also a drying oil like linseed, but hempseed oil contains a larger amount of the fatty acid linoleic acid and a smaller amount of linolenic acid (http://en.wikipedia.org/wiki/Hempseed_oil). This might mean that oil paint based on hempseed-oil instead of linseed-oil might have fewer problems with yellowing.Experiments with the two oils have been executed side by side in order to compare results. Two oil paints have also been produced and tested. Test pieces painted with the two different oil paints were exposed to moisture, daylight and complete darkness and then compared.</p>

This study describes the mechanical response of thermoset polymers under high compressive loads. The study is divided into two parts. The first part focuses on the behaviour of a powder coating when used in a clamping force joint and how the properties vary when the chemical and physical structure of the coating is changed. The second part discusses the fundamental understanding of the behaviour of thermoset polymers with small thickness-to-width ratio subjected to compressive stresses, the aim being to develop mathematical material models for viscoelastic materials under high compressive loads. In the first part polyester powder coatings were used with variations in molecular weight, number of functional groups of the resin, amount and type of filler and thickness of the coating. The coatings were subjected to conventional tests for coatings and polymers and also to specially designed tests developed to study the behaviour of powder coatings in clamping force joints. The high compressive loads in a clamping force joint put high demands on the relaxation and creep resistance of the coating and the study shows the importance of crosslink density, filler content, and also coating thickness in order to achieve the desired mechanical properties of a coating. A high reactivity of the resin, facilitating a high crosslink density and hence a high Tg, is the most important property of the coating. A film with high crosslink density shows increase in relaxation time and in apparent yield strength under compression, and also an increase in relaxation modulus and storage modulus in tension at temperatures above Tg. Addition of fillers reduces the deformation during compression and tension, but also induces a lower strain at break and hence a more brittle coating. The reinforcing effect of the fillers is pronounced when increasing the crosslink density of the coating, especially in the compression tests. The effect is evident in compression even at low amounts of fillers, where the relaxation time and resistance to deformation are strongly increased. The combination of high crosslink density and addition of fillers is therefore desirable since fillers then can be used moderately in order to achieve a reinforcing effect in compression while minimising embrittlement. The study also showed that increased coating thickness will give rise to defects in the coating, especially voids and blisters due to evaporation of water formed during the curing of the polyester powder coating. These defects will give rise to stress concentrations and increased plastic deformations in the coating, impairing the properties of the clamping force joint. The results from relaxation tests in tension were used to create a micromechanical model. This model was used in finite element modelling to estimate the loss of clamping force in a screw joint and to correlate with the experimental results of the powder coatings. In the second part of the study a well-defined free radically cured vinyl ester resin was used and studied in six different geometries in order to determine the dependence of apparent mechanical properties on the particular size and shape of a sample when it is subjected to high compressive loads. Variation of the specimen thickness, boundary conditions and loading conditions reveals that the geometry of the sample has a significant effect on the mechanical performance of the polymer. The apparent modulus and the yield strength increase dramatically when the thickness-to-width ratio of the sample is reduced, whereas they decrease when the friction between the sample and the compression plate is reduced. The creep strain rate decreases when the thickness of the material is reduced and it decreases even more when the amount of material surrounding the compressed part of the sample is increased. Creep and strain recovery tests on large specimens were used to develop a mathematical model including non-linear viscoelastic and viscoplastic response of a thermoset vinyl ester. The model was used in FEM calculations where the experimental results were compared with the calculated results in order to model the trends of the material response when varying the sample geometry. / QC 20100921

The varieties of paint are today very big, but many of the more popular paints are less than environmental friendly. The uses of fossilized fuel in paints are common because these paints dry fast and are color true. It would be beneficial for the environment if more renewable source were used to produce paint. Linseed oil is an old base for oil paints. It is renewable and easily procured. But linseed oils have some aspects that give it a bad reputation. There are problems with the slow drying and the color turning yellow when exposed to darkness for long periods of time. Researchers at KTH have connected the yellowing to linolenic acid, one of the common fatty acids in linseed oil (Svensson, M. Johansson, M, Stenberg, C. Samuelsson, J. 2003). Hempseed oil is also a drying oil like linseed, but hempseed oil contains a larger amount of the fatty acid linoleic acid and a smaller amount of linolenic acid (http://en.wikipedia.org/wiki/Hempseed_oil). This might mean that oil paint based on hempseed-oil instead of linseed-oil might have fewer problems with yellowing.Experiments with the two oils have been executed side by side in order to compare results. Two oil paints have also been produced and tested. Test pieces painted with the two different oil paints were exposed to moisture, daylight and complete darkness and then compared.

Detta examensarbete är utfört på Möbelsnickeriprogrammet på Carl Malmsten - Centrum för Träteknik och Design i Stockholm. Om man som Möbelsnickare har ambitionen att utveckla och förnya hantverket är det nödvändigt att ha kunskap och kännedom om historiens hantverkstekniker och material. Intarsia, att med tunna träfaner skapa dekorativa mönster och motiv på möbler, är ett typexempel på en sådan teknik. I historien var det genom intarsian som tekniken att färga faner utvecklades. Vilka metoder och material använde man sig av förr? Hur kan en genomfärgningsprocess se ut idag? Hur kan genomfärgat material användas i ett modernt sammanhang? Kan genomfärgat faner vara ett verktyg för att utveckla intarsian och skapa något nytt inom möbelhantverket? Dessa är en del av de frågor som hanteras i rapporten. Syftet med examensarbetet är att undersöka vilken metod och vilka material som är mest lämpliga för att genomfärga faner i mindre skala. Genom studier och samtal med lärare och hantverkare hämtas fakta om vilka material och metoder som användes förr. Med denna kunskap som grund utförs experiment med ett antal utvalda färgämnen för att finna en lämplig metod. Förekommande svårigheter som uppstod under experimenten är att faneren inte helt penetreras av färglösningen eller att färgen inte är den önskvärda. Det kunde dock konstateras att om faneren dränkes under en viss tid i en spritlöslig färgblandning åstadkommes ett gott resultat. Med kunskap om hur faner genomfärgas formges en produkt där det färgade materialet används i en intarsia, Ett antal bilder fungerar som inspirationsmaterial och motivet ritas med utgångspunkten att det skall vara nyskapande och samtida. Resultatet av arbetet är en beskrivning i hur man genomfärgar faner och visar hur detta kan gå till i praktiken. Dessutom diskuteras möjligheterna att använda ett sådant material för att förnya och utveckla hantverkstekniken intarsia. / This exam work is executed at the fine woodworking course at Carl Malmsten – Center for Wood Technology and Design in Stockholm. If you as a cabinetmaker and fine woodworker have the ambition to renew and develop the craft, it is necessary to have knowledge of and insights in traditional techniques and materials. Marquetry, the use of thin wood veneer to create patterns and motives in furniture, is such a technique. In history, it was through marquetry that the technique to dye and stain veneers was developed. Which methods and materials were used in those days? What can a process of dying through veneers look like today? How can dyed-through material be used in a modern context? Can it be used as a tool to develop marquetry and create something new within the woodcraft? These are a few of the questions that are discussed in this work. The purpose of the exam work is to examine which method and materials are most suitable for this dying-through process on a smaller scale. By studying and interviewing teachers and craftsmen, facts were gathered about methods and materials that are used traditionally. With this knowledge a series of experiments are performed with different selected dyestuffs to find a suitable method. Some difficulties that occurred during these experiments were that the solution did not penetrate the veneers fully and that the colour was not the expected one. However, the conclusion was that if the veneers were drenched in a solution of spirit based dyestuff for a certain time span the result was sufficient. With the knowledge of how to dye-through veneer a product is designed where the dyed material is used in a marquetry motif. A series of images work as a source of inspiration and the resulting motif is contemporary and modern in design. The result of the exam work is a description of how to dye-through veneer and shows how this can be performed in a practical situation. Furthermore, the possibilities of using this material, in order to renew and develop the art of marquetry, are explored.

No description available.

<p>Detta examensarbete är utfört på Möbelsnickeriprogrammet på Carl Malmsten - Centrum för Träteknik och Design i Stockholm. Om man som Möbelsnickare har ambitionen att utveckla och förnya hantverket är det nödvändigt att ha kunskap och kännedom om historiens hantverkstekniker och material. Intarsia, att med tunna träfaner skapa dekorativa mönster och motiv på möbler, är ett typexempel på en sådan teknik.</p><p>I historien var det genom intarsian som tekniken att färga faner utvecklades. Vilka metoder och material använde man sig av förr? Hur kan en genomfärgningsprocess se ut idag? Hur kan genomfärgat material användas i ett modernt sammanhang? Kan genomfärgat faner vara ett verktyg för att utveckla intarsian och skapa något nytt inom möbelhantverket? Dessa är en del av de frågor som hanteras i rapporten.</p><p>Syftet med examensarbetet är att undersöka vilken metod och vilka material som är mest lämpliga för att genomfärga faner i mindre skala. Genom studier och samtal med lärare och hantverkare hämtas fakta om vilka material och metoder som användes förr. Med denna kunskap som grund utförs experiment med ett antal utvalda färgämnen för att finna en lämplig metod. Förekommande svårigheter som uppstod under experimenten är att faneren inte helt penetreras av färglösningen eller att färgen inte är den önskvärda. Det kunde dock konstateras att om faneren dränkes under en viss tid i en spritlöslig färgblandning åstadkommes ett gott resultat.</p><p>Med kunskap om hur faner genomfärgas formges en produkt där det färgade materialet används i en intarsia, Ett antal bilder fungerar som inspirationsmaterial och motivet ritas med utgångspunkten att det skall vara nyskapande och samtida.</p><p>Resultatet av arbetet är en beskrivning i hur man genomfärgar faner och visar hur detta kan gå till i praktiken. Dessutom diskuteras möjligheterna att använda ett sådant material för att förnya och utveckla hantverkstekniken intarsia.</p> / <p>This exam work is executed at the fine woodworking course at Carl Malmsten – Center for Wood Technology and Design in Stockholm. If you as a cabinetmaker and fine woodworker have the ambition to renew and develop the craft, it is necessary to have knowledge of and insights in traditional techniques and materials. Marquetry, the use of thin wood veneer to create patterns and motives in furniture, is such a technique.</p><p>In history, it was through marquetry that the technique to dye and stain veneers was developed. Which methods and materials were used in those days? What can a process of dying through veneers look like today? How can dyed-through material be used in a modern context? Can it be used as a tool to develop marquetry and create something new within the woodcraft? These are a few of the questions that are discussed in this work.</p><p>The purpose of the exam work is to examine which method and materials are most suitable for this dying-through process on a smaller scale. By studying and interviewing teachers and craftsmen, facts were gathered about methods and materials that are used traditionally. With this knowledge a series of experiments are performed with different selected dyestuffs to find a suitable method. Some difficulties that occurred during these experiments were that the solution did not penetrate the veneers fully and that the colour was not the expected one. However, the conclusion was that if the veneers were drenched in a solution of spirit based dyestuff for a certain time span the result was sufficient.</p><p>With the knowledge of how to dye-through veneer a product is designed where the dyed material is used in a marquetry motif. A series of images work as a source of inspiration and the resulting motif is contemporary and modern in design.</p><p>The result of the exam work is a description of how to dye-through veneer and shows how this can be performed in a practical situation. Furthermore, the possibilities of using this material, in order to renew and develop the art of marquetry, are explored.</p>

<p>The papermaking industry uses a large amount of starch each year, both as a wet-end additive and as a rheological modifier in surface sizing and coating colors. It is important to be able to reduce the amount of chemicals used in the papermaking and surface treatment process, to reduce costs and to make the process even more efficient. Interest in new high-performance starches is great. By using these new types of starches, improved recycling of barrier products may be obtained as well as a reduction in the use of synthetic sizing agents. The objectives of this work were to understand the behavior of temperature-responsive hydrophobically modified starches, where the solubility in water simply can be adjusted by temperature or by polymer charge, to improve the barrier properties, like the water vapor permeability, mechanical properties and water resistance (Cobb and contact angle) of papers surface sized by starch-containing solutions, and to investigate the potential for industrial use of these temperature-responsive starches. It was demonstrated that the temperature-responsive starches phase separate upon cooling and, depending on the charge density of the starch, a particulate precipitation or a gel-like structure was obtained. The starch with zero net charge showed a larger increase in turbidity than the starch with a cationic net charge, indicating that particulate precipitation is favored by a zero net charge and that the formation of a gel network is favored by charged starch molecules. Further, the starches formed inclusion complexes with surfactants, giving stabilization to the starches in the presence of surfactants. The net charge density of the starch and the charge of the surfactant determined whether or not an inclusion complex would form between them. Important mechanisms for the stability of the starch seemed to be formation of mixed micellar-like structures between the hydrophobic chain of the starch and the surfactant along the starch backbone in addition to formation of inclusion complexes between the starch and the surfactant. The hydrophobically modified starches showed higher hydrophobic surface character when applied to the paper surface above the critical phase separation temperature than with application at room temperature. Free films of the temperature-responsive starches showed good barrier against oxygen, but no barrier against water vapor. The mechanical properties decreased with addition of glycerol to the films.</p>

The papermaking industry uses a large amount of starch each year, both as a wet-end additive and as a rheological modifier in surface sizing and coating colors. It is important to be able to reduce the amount of chemicals used in the papermaking and surface treatment process, to reduce costs and to make the process even more efficient. Interest in new high-performance starches is great. By using these new types of starches, improved recycling of barrier products may be obtained as well as a reduction in the use of synthetic sizing agents. The objectives of this work were to understand the behavior of temperature-responsive hydrophobically modified starches, where the solubility in water simply can be adjusted by temperature or by polymer charge, to improve the barrier properties, like the water vapor permeability, mechanical properties and water resistance (Cobb and contact angle) of papers surface sized by starch-containing solutions, and to investigate the potential for industrial use of these temperature-responsive starches. It was demonstrated that the temperature-responsive starches phase separate upon cooling and, depending on the charge density of the starch, a particulate precipitation or a gel-like structure was obtained. The starch with zero net charge showed a larger increase in turbidity than the starch with a cationic net charge, indicating that particulate precipitation is favored by a zero net charge and that the formation of a gel network is favored by charged starch molecules. Further, the starches formed inclusion complexes with surfactants, giving stabilization to the starches in the presence of surfactants. The net charge density of the starch and the charge of the surfactant determined whether or not an inclusion complex would form between them. Important mechanisms for the stability of the starch seemed to be formation of mixed micellar-like structures between the hydrophobic chain of the starch and the surfactant along the starch backbone in addition to formation of inclusion complexes between the starch and the surfactant. The hydrophobically modified starches showed higher hydrophobic surface character when applied to the paper surface above the critical phase separation temperature than with application at room temperature. Free films of the temperature-responsive starches showed good barrier against oxygen, but no barrier against water vapor. The mechanical properties decreased with addition of glycerol to the films.