In recent years, antibacterial surfaces have been a subject of increased interest. Especiallyinteresting are non-leaching, contact-active surfaces that physically disrupts the bacterialcell using immobilised cationic polymers. Thus the risks of bacterial resistance and discharge of hazardous biocides is minimised. The assembly of such surfaces is elaborate andusually involves organic solvents. Here, polyelectrolyte multilayers (PEM) are proposed as an effective surface modification method, with an overall goal of producing antibacterial cellulose fibres. The PEM process is based on physical adsorption of oppositely charged polymers in aqueous solutions. Multilayers were formed with the bactericidal polymer polyvinylamine (PVAm) and polyacrylic acid. PVAm compounds with hydrophobic modificationswere applied as well, as they possess increased antibacterial activity in solution. In this work, the multilayer formation was studied on model surfaces of silicone oxide and glass in order to obtain fundamental knowledge of the polymer system. QCM-D and reflectometry, which detect total mass including bound water and polymer mass only, respectively, were used to analyse the layer formation. Salt-concentrations were varied at 1, 10 or 100 mM NaCl. A stepwise multilayer formation with exponential-like polymer adsorption but with decreasing water content for each layer was seen at all salt concentrations.A higher salt concentration resulted in an increased adsorbed mass. No significant differences in adsorption between the modified and unmodified PVAm could be detected. AFM imaging applied to multilayers having nine layers showed large surface aggregates under high salt conditions for the C6-modified PVAm. Dynamic light scattering showed that the polymer occurred as single molecules in solution; hence it was concluded that theaggregation is surface-associated. The multilayers were then tested for bacterial growth inhibition. The relative bacterial inhibition was time-dependent, as the surface was saturated with bacteria over time. After two hours, a maximal inhibition of 99 % could be observed for the multilayers. After eight hours, a moderate inhibition of less than 40 % was detected. Using multilayers affected the results positively compared to single layers. After three layers, though, no further reductionwas seen. Viability staining of the surface-adhered bacteria revealed that the adhered bacteria had intact membranes. Therefore, the microbiological properties of the multilayers can at this point be described more as growth-inhibiting by bacterial adhesion effectsthan as biocidal. However, this work has shown the importance of combining surface characterisation and microbial testing to understand the bacteria-surface interaction. / Biointeractive fibres

In Sweden, paperboard has been an essential product in the export market and is mainly used as packaging material. Packaging materials corresponded to 66% of all paper and board production in Sweden for the year 2020, which is an increase of 2,5% compared with the previous year [1]. The main function of the packaging is to protect the content inside from physical, chemical, and biological contamination [2]. Usually, paper boards are coated with pigment coatings to improve printing properties of the paperboard. Expancel microspheres are small plastic hollow spheres, which can improve the compressive properties of the paperboard. The purpose of this study is to investigate how Expancel microspheres affects the pigment coating, runnability and coated paper boards [30,31].Iggesund mill located in Iggesund manufacturer and coats high-quality paper boards. The coating formulas are based on existing recipes from the mill. The formulas where adjusted so that 12vol%,37vol% and 50 vol% of the pigments consisted of Expancel microspheres. Two different types of Expancel microspheres were used, one type of microspheres with a density of 80g/L and the other type had a density of 148g/L. To investigate how the microspheres affects the pigment coating the pH, dry content, ash content, viscosity, water retention and density were measured on the pigment coating. The paperboards were coated with pigment coating, containing different volume percentages of microspheres. The paperboard tests included gloss, surface roughness, grammage, thickness, compressibility contact angle and water adsorption.The mixture with 50 vol% of the pigments containing of microspheres with the density of 148g/L had a low pH value which can affect the results of the measurements as the pigment particles are not fully separated from each other. The low pH value resulted that the mixture had a high viscosity, which can create runnability problems. The increased number of microspheres resulted in decreasing solid content and density. The low solid content requires more energy for drying. The increasing amount of microspheres with a density of 80g/L showed an increasing viscosity with Hercules Hi-Shear. The high viscosity in Hercules Hi-Shear show that more force will be required to pump the coating mixture and that the flow in the pipes will be slower at higher viscosity.There is a difference between calculated thickness and the measured thickness of the coated paper boards. Calculated thickness where almost always less than the measured. The SEM(scanning electron microscope)-images showed that the microspheres affected the3thickness of the coated paper board. The size and shape of the particles affected the gloss. The higher content of carbonate 90(C90) resulted in higher gloss. The addition of microspheres lowered the gloss of the coated paperboards. Compressibility on the paperboard increased with the increasing addition level of microspheres. The SEM images showed that higher number of microspheres on the surface of the paperboard increased the compressibility of the surface. The contact angel measurement showed that the coating mixture containing of 50vol% with the density of 80g/L hade the highest contact angel. The Cobb60 method was used to examine the water adsorption the coated paper boards. The paper boards coated with mixtures containing the microspheres of density 80g/L had the lowest Cobb60-values.

Denna rapport handlar om ett produktutvecklingsprojekt genomfört som examensarbete för högskoleingenjörsprogrammet i innovationsteknik och design vid Karlstads universitet. Uppdraget tillhandahölls av Biosorbe AB som tillverkar ett material med namnet GreenAll. GreenAll är i grunden pappersmassa behandlat med kemikalier vilket har skapat goda oljeabsorberande samt vattenavstötande egenskaper. Projektet har sökt ett biobaseratalternativ av oljematta på en idag plastdominerad marknad där GreenAll önskats implementeras. Konsumtion av plast är ett internationellt problem som idag skapar stora skador på djur och natur. Oljemattor används i förebyggande syfte vid arbete eller situationer där det finns risk för oljespill. Idag sorteras uttjänta oljemattor på återvinningscentraler och fraktas sedan till förbränningsanläggningar där de bränns och blir till energi. Oljemattor av plast kan tvättas, men det sker inte alltid på rätt sätt där konsekvensen blir att farligt avfall hamnar i naturen. Målet med arbetet har varit att utveckla ett koncept som gör det möjligt att tillverka en biobaserad oljematta som är tilltalande för användaren samt ta fram ett första utkast till prototyp. Framtagen produkt ska genomsyras av hållbar utveckling och minska miljöpåverkan genom goda materialval. Arbetet har följt metoder för den industriella produktutvecklingsprocessen med grund i designprocessen. Med materialet GreenAll som grund resulterade arbetetet i ett koncept på en cellulosabaserad oljematta som sammanfogades genom sömnad och limning. Oljemattan består utav juteväv, linnevaxduk och GreenAll samt att mattan har fått namnet Slurp. Lösningen anses vara bättre för miljön, bidrar till en minskad plastkonsumtion och förhindrar att farligt avfall hamnar i naturen. Enligt en teoretiskt grund finns det möjlighet till delvis återvinning och utvinning av uttjänt olja som absorberats av mattan. / This report is about a product development project carried out as a degree project for the Bachelor of Science in Innovation Technology and Design at Karlstad University. The assignment was provided by Biosorbe AB, which produces a material called GreenAll. GreenAll is basically paper pulp treated with chemicals which has created good oil absorbing properties and given the material a water repellent property. The project has sought a bio-based alternative to oil mats in a currently plastic-dominated market where GreenAll is desired to be implemented. Consumption of plastic is an international problem that today causes great damage to animals and nature. Oil mats are used for preventive purposes in work or situations where there is a risk of oil spillage. Today, used oil mats are sorted at recycling centres and then transported to incineration plants where they are burned and turned into energy. Plastic oil mats can be washed, but this is not always done properly, with the result that hazardous waste ends up in the environment. The aim of the work has been to develop a concept that makes it possible to produce a bio-based oil mat that is appealing to the user and to produce a first draft of a prototype. The product developed should be permeated by sustainable development and reduce environmental impact through good material choices. The work has followed methods of the industrial product development process based on the design process. Using the material GreenAll as a basis, the work resulted in a concept of a cellulose-based oilmat that was joined by sewing and gluing. The oil mat consists of jute fabric, linen wax cloth and GreenAll and the mat has been named Slurp. The solution is considered to be better for the environment, helping to reduce plastic consumption and preventing hazardous waste from entering the environment. According to a theoretical basis, there is a possibility of partial recycling and recovery of used oil absorbed by the carpet.

Clean water is necessary for human survival and there is a need for development of cheap and easy water purification techniques to use in emergency situations when there is no access to safe drinking water. Bacteria contaminated water can cause lethal diarrheal diseases and is globally the second most common cause of death among children less than five years of age. Bacteria adsorbing filter paper made from cellulose could be an environmentally and economically sustainable alternative for disposable water purification filters. This thesis investigates the possibility to use polyelectrolyte multilayer modified cellulose pulp fibers and filter papers to adsorb and remove bacteria from water. The bacterial removal efficiency of the modified materials has been tested both in suspension and through filtration. The surface modification provides the cellulose fibers with a positively charged surface that can attract and bind the negatively charged bacteria. The bacterial adsorption through electrostatic interactions makes it possible to remove bacteria, even when the pore size of the cellulose filters is larger than bacteria. Bacterial reduction tests shows that it is possible to remove over 99.9 % of the bacteria when filtering water through the modified materials. An increased amount of adsorbed cationic polyelectrolyte, polyvinylamine, resulted in an increased bacterial removal capacity. It has also been shown that the bacterial removal efficiency increases with an increased the amount of bacteria adsorbing materials in the filter. The modified materials have been compared with a commercial product and the filtration efficiency has shown to be greater for the polyelectrolyte-modified materials, under the test conditions used in this thesis. Tests with natural water samples shows that it is important to use a filtration mode to remove particles from the water in combination with the bacterial adsorption, as the particles interfere with the bacterial adsorption. / Säkert dricksvatten är nödvändigt för överlevnad och det finns ett stort behov av att utveckla nya billiga och enkla tekniker för att rena vatten i nödsituationer där det inte finns tillgång till detta. Dricksvatten förorenat av bakterier kan orsaka dödliga diarrésjukdomar och är globalt den näst vanligaste dödsorsaken bland barn under fem år. Denna avhandling undersöker möjligheten att använda cellulosafibrer och filterpapper, ytmodifierade med multilager av katjoniska polyelektrolyter, för att adsorbera och avlägsna bakterier från vatten. Bakterieradsorberande filterpapper tillverkat av cellulosa kan vara ett miljövänligt och ekonomiskt hållbart alternativ för vattenreningsfilter för engångsbruk. De modifierade materialens förmåga att adsorbera bakterier har testats både i suspension och via filtrering. Ytmodifieringen ger cellulosafibrerna en positivt laddad yta som kan attrahera och binda de negativt laddade bakterierna. Avlägsnandet av bakterier genom elektrostatisk interaktion gör det möjligt att ta bort bakterier, även när filtret har en porstorleken som är större än bakterierna. Bakteriereduktionstesterna visar att det är möjligt att avlägsna mer än 99,9 % av bakterierna vid filtrering genom de modifierade materialen. En ökad mängd adsorberad katjonisk polyelektrolyt, polyvinylamin, resulterade i en ökad bakterieavlägsningskapacitet. Det har också visat sig att effektivitet ökar väsentligt med ökad mängd bakterieadsorberande material i vattenfiltren. De ytmodifierade materialen har jämförts med en kommersiell produkt för vattenrening med goda resultat. Filtreringstesterna utförda i den här avhandlingen visar att de modifierade materialen tar bort mer bakterier än vad det kommersiella filtret inaktiverar. Tester med naturliga vattenprov visar att det är viktigt att använda filtrering för att avlägsna partiklar från vattnet för att uppnå en önskad bakterieadsorption, eftersom partiklarna påverkar bakterieadsorptionen och minskar effektiviteten hos de bakterieadsorberande materialen / <p>QC 20170328</p>

The failure properties of interfibre bonds are the key for the build-up of strength in fibrous materials such as paper and paperboard. In order to tailor the properties of such materials by chemical or mechanical treatments and to learn how such modifications influence the properties at a microscopic level, direct measurement of individual fibre--fibre crosses are typically performed. However, the state of loading in the interfibre joint, in testing of individual fibre--fibre crosses, is in general very complex and a greater understanding for how to evaluate the mechanical properties of interfibre joints is desirable. In Paper A, a method for manufacturing multiple fibre--fibre cross specimens and a procedure for testing interfibre joints at different modes of loading is presented. The method is applied to investigate the strength of fibre-fibre crosses with different geometry and at two principally different modes of loading. Also, an investigation on the influence of drying pressure, the drying method as well as a comparison of pulp fibres from two different degrees of refining is presented. The force at rupture is scaled in terms of different geometric parameters; nominal overlap area, length and width of the joint region. It is shown that neither of the methods of scaling unambiguously reduced the coefficient of variation of the mean strength and that the force at rupture in a peeling type of loading was about 20% of the ones tested in the conventional shearing type of loading. In Paper B, a procedure for evaluating interfibre joint strength measurements in terms of resultant forces and moments at rupture is presented. The method is applied to investigate the state of loading in fibre-fibre crosses tested in two principally different modes of loading. It is shown that for a typical interfibre joint test, the modes of loading other than pure shear, cannot in general be neglected and is strongly dependent on the structural geometry of the fibre-fibre crosses. Also, the stress state in the interface centroid was estimated in order to quantify how the mode of loading influence the amount of normal stresses that develop in relation to the amount of shear stresses in the interfibre joint. / De brottmekaniska egenskaperna hos fiberfogar är nyckeln för uppbyggnaden av styrka hos fibrösa material såsom papper och kartong. För att effektivt skräddarsy sådana materials egenskaper genom kemisk eller mekanisk behandling och för att förstå hur sådana modifieringar påverkar egenskaperna på en mikroskopisk nivå är provning av individuella fiber-fiber-kors en allmänt använd metod. Belastningen i en fiberfog vid provning av individuella fiber-fiber kors är dock generellt mycket komplicerad och ytterligare kunskap om hur fiberfogars mekaniska egenskaper skall utvärderas är önskvärd. I Artikel A, presenteras en metod för samtidig tillverkning av flera fiber-fiber kors samt en metod för mekanisk provning av dessa med olika typer av belastning. Metoden tillämpades för att studera styrkan av fiber-fiber-kors med olika geometri och vid två olika lastfall. En undersökning av hur torktrycket, torkmetoden samt graden av malning inverkar på fogstyrkan presenteras. De uppmätta brottlasterna skalades med olika karakteristiska längder för fogen; nominell överlapparea samt fogens längd och bredd. Resultaten visade att ingendera av normaliseringsmetoderna reducerade variationskoefficienten (av medelvärdet av styrkan) samt att brottlasten för en globalt fläkande belastning var omkring 20 % av brottlasten för prov utförda med den konventionella skjuvande belastningen. I Artikel B, presenteras en metod för utvärdering av mätningar av styrkan hos fiberfogar med hänseende på kraft- och moment- resultanterna i gränsytan mellan fibrerna. Metoden används för att studera belastningsmoden hos fiber-fiber--kors provade i två principiellt olika lastfall. Resultaten visar att för ett typiskt fiberfogsprov av isolerade fiber-fiber-kors med långa fria fibersegment, så kan inte belastningsmoderna vid sidan av skjuvning försummas och att de är starkt beroende av fiber-fiber-korsets geometri. För att kunna jämföra fiberfogar av olika storlek och kvantifiera förhållandet mellan normal- och skjuvbelastningen i fogen skalades de resulterande krafterna och momenten med tvärsnittsstorheter baserade på en approximation av fogareans utformning. / <p>QC 20130125</p> / BiMaC Innovation

The LignoBoost process is a valuable supplement to the Kraft process. It can increase the pulp production rate of a Kraft mill and it enables lignin separation from black liquor with a high degree of purity. However, residual xylan in black liquor has been observed to increase filtration resistance of lignin during the LignoBoost process. In order to uncover underlying mechanisms, this thesis investigates the potential influence of xylan during lignin precipitation and filtration, which are the two main steps of the LignoBoost process. For this purpose experiments based on a model system were designed. Model liquors consisted of lignin and xylan as the only organic compounds and contained lower salt concentrations (4.2-5.9 wt%) compared to black liquor. Furthermore, reference liquors were prepared without xylan addition. Precipitation mechanisms were studied in the onset precipitation region (i.e. alkaline regime) by in-situ focused beam reflectance measurements (FBRM) during step-by-step acidic precipitation of the model liquor. It was found that the onset precipitation pH does not change with the presence of xylan as all liquors started precipitation around pH 9.15. The filtration process was investigated on model liquors that had been precipitated by fast acidification to acidic regimes (pH 6.5-2.87). The use of FBRM during acid precipitation of model liquors suggested that temperature had a significant influence on the chord length distribution (CLD) of the particles. In all filtration experiments, a decrease in CLD was observed when the temperature was changed from 80 °C to 25 °C. Moreover, this thermal instability of particles seemed to be higher when added xylan was present in the liquor. The investigation of the resulting filer cakes with HPLC showed that xylan was evenly distributed through the cake. Further findings on the influence of xylan were impeded due to variations in ionic strength in the model liquors. It was found that the effect of ionic strength on filtration properties and particle sizes overshadows the effect of xylan. Higher ionic strength was observed to yield a lower filtration resistance, a higher solidosty, larger particles and lower solid surface area, as investigated by filtration measurements, laser diffraction and BET analysis. Finally, xylan was fluorescently tagged (i.e. dyed) with Remazol Brilliant Blue R to investigate xylan position in the ligninxylan filer cake, using a confocal fluorescence microscope. However, due to the autofluorescence of lignin as well as low emission intensity of the synthesized dyed xylan, xylan could not been tracked within the lignin particle. Nevertheless, valuable insight was gained into the preparation of dyed xylan and the bond stability.

Résumé non communiqué par le doctorant. / Résumé non communiqué par le doctorant.

The thesis investigates the modification of paper into an ion- and electron-conductive material, and as a renewable material for electronic device. The study stretches from investigating the interaction between the cellulosic materials and the conducting polymer to demonstrating the performance of the conductive paper by printing the electronic structure on the surface of the conductive paper. Conducting materials such as conducting polymer, ionic liquids, and multi-wall carbon nanotubes were deposited into the fiber networks. In order to investigate the interaction between the conducting polymer and cellulosic material, the adsorption of the conducting polymer poly(3,4-ethylenedioxythiophene): poly(4-styrene sulfonate) (PEDOT:PSS) onto microcrystalline cellulose (MCC) was performed. Electroconductive papers were produced via dip coating and rod coating, and characterized. The Scanning Electron Microscopy (SEM) / Energy Dispersive Spectroscopy (EDS) images showed that the conducting polymer was deposited in the fiber and in fiber-fiber contact areas. The X-ray Photoelectron Spectroscopy (XPS) analysis of dip-coated paper samples showed PEDOT enrichment on the surface. The effects of fiber beating and paper formation, addition of organic solvents and pigments (TiO2, MWCNT), and calendering were investigated. Ionic paper was produced by depositing an ionic liquid into the commercial base paper. The dependence to temperature and relative humidity of the ionic conductivity was also investigated. In order to reduce the roughness and improve its printability, the ionic paper was surface-sized using different coating rods.  The bulk resistance increased with increasing surface sizing. The electrochemical performance of the ionic paper was confirmed by printing PEDOT:PSS on the surface. There was change in color of the polymer when a voltage was applied. It was demonstrated that the ionic paper is a good ionic conductor that can be used as component for a more compact electronic device construction. Conductive paper has a great potential to be a flexible substrate on which an electronic structure can be constructed. The conduction process in the modified paper is due to the density of charge carriers (ions and electrons), and their short range mobility in the material. The charge carrying is believed to be heterogeneous, involving many charged species as the paper material is chemically heterogeneous. / <p>Fel ordningsnummer (2010:28) är angivet på omslaget av fulltextfilen.</p> / Printed Polymer Electronics on Paper

The understanding of what properties the fibre should have in order to give the right end-product paper properties, along with the type of processing, is a subject for a lot of research and development. Today the ability to measure fibre properties on-line is widely used for pulps. It is often necessary to measure many properties and variables in a process. The data collected is therefore almost always multivariate. It is very hard to analyse process data due to a lot of noises. Correlations between fibre and paper properties are hard to find, but this does not mean that correlations do not exist. Fibre properties, measured by the pulp analyser PulpEye, were investigated and correlations to paper properties were studied. The work was divided into three different studies. Study 1 was an investigation of historical process data, in study 2 pulp samples from the production was analysed and study 3 was a refiner setting trial, were different refiner segments, flows through refiners and intensities were studied. Both the group-plots and MVDA’s based on the historical process data in study 1, showed that the Scott Bond was increased with increased amount of kinks and curl for the unbleached pine pulp (softwood pulp). Coarseness measurements, made in the study of historical data, indicated that the coarseness was varying in such a large extent that it was believable that it had effects in the papermaking process. Another interesting fibre property, investigated in the refiner setting trial, was crill. The amount of crill is said to have strong correlation to paper strength. The analysis showed that the incoming pulp had different amount of crill and that the amount of crill after the refiners also was varying for the different samples. The development of crill at different kappa numbers and for pulps refined with different segments and refiner strategies should be further investigated. In this work it has been difficult to find correlations between fibre properties and paper properties in the refiner setting trial. This could have been due to small variations of the different parameters. This work showed that the normal production can be handled very well and variations are rather small. It can be seen though, that problems do appear when parameters are deviating from the normal case. An efficient way to work is to do measurements when the incoming pulp parameters are deviating. It should also be more investigated how the most common deviating pulp parameters should be handled in the refining process and at the board machine. The communication between the pulp production and the board machines is recommended to be further developed, especially when the pulp production have disturbances that can be affecting the refining and further the board production.

Vid TCF-blekning av pappersmassa är väteperoxid en av huvudkemikalierna. I dagsläget är det svårt att styra blekstegen. Operatörerna måste ta hänsyn till produktionstakt, blekbarheten på massan varierar och fördröjning i trender. PO-bleksteget på Södra Cell Värö har en ungefärlig uppehållstid på 4 timmar och det är först efter så lång tid som man kan se hur en förändring verkligen slår igenom. Överblekning kostar väldigt mycket i kemikalieåtgång och det är därför efterfrågat ett sätt att kunna styra och optimera peroxidblekningssteget. Ett delsteg för detta var att simulera steget experimentellt och från dessa data ta fram en matematisk modell som förutsäger ljusheten. Massa togs ut från fabriken och blektes på labb under kontrollerade förhållanden med satsningar liknande verkliga i fabriken. De parametrar som studerades på labb var temperatur, väteperoxidsats och alkalisats då de påverkar ljusheten mest. En modell för ljushetsökning anpassades sedan till framtagna blekdata. Ekvationer för förbrukning av väteperoxid och hydroxidjoner togs också fram från analyser på blekfiltraten. Med ingående parametrar som startkoncentrationer av kemikalier, temperatur och massakoncentration förutsäger modellen ljusheten väl vid verifiering jämfört med fabrik och verifieringsblekning på labb. Modellen ligger något högre jämfört med fabrik men det var förväntat då förhållanden på labb ger ett renare system. För de parametrar som studerats anpassade sig modellen bra till förändringar och vid verifiering på labb syntes att modellen även svarade med en korrekt ljushet vid förändring i massakoncentration och ingående ljushet i steget. / During TCF-bleaching of pulp, hydrogen peroxide is one of the main chemicals. Today it is difficult to control the bleaching stages. The process operators must consider the production rate, changes in the bleach ability of the pulp and delays of trends in the control system. The PO-bleaching stage at Södra Cell Värö has approximately a retention time of four(4) hours and it is first after that, a result of a change in the process can be seen. Overbleaching is expensive due to high chemical need and therefore it is requested to find a way to control and optimize the peroxide bleaching stage. One way to do this was too simulate the stage experimentally and from those kinetic data accomplish a mathematical model that predicts the brightness increase of the pulp. Pulp from the mill was bleached at the laboratory under controlled conditions and with charges similar to what are used in the plant. The parameters that were studied at lab were temperature, hydrogen peroxide charge and alkali charge as they affect the brightness mostly. A model for brightness increase was adjusted to the achieved bleaching data. Equations for consumption of hydrogen peroxide and hydroxide anions were also developed from analyses of the bleaching filtrates.  From the start parameters, as concentration of the chemicals, temperature and pulp concentration, the model predicts the brightness well according to verification of data from mill and verification bleaching at laboratory. The value from the model is somewhat higher compared to that of the plant but that was expected due to the fact that the conditions at lab give a cleaner system. For those parameters that were studied, the model did adjust well to changes made and according to the verification at lab it was seen that the model also worked for changes in pulp concentration and different brightness at the beginning of the stage.