The thesis focuses on exploring the sub-grain structure in stainless steel 316L prepared by additive manufacturing (AM). Two powder-bed based AM methods are involved: selective laser melting (SLM) and electron beam melting (EBM). It is already known that AM 316L has heterogeneous property and hierarchy structure: micro-sized melt pools, micro-sized grains, nano-sized sub-grain structure and nano-sized inclusions. Yet, the relation among these structures and their influence on mechanical properties have not been clearly revealed so far. Melt pool boundaries having lower amount of sub-grain segregated network structures (Cellular structure) are weaker compared to the base material. Compared with cell boundaries, grain boundaries have less influence on strength but are still important for ductility. Cell boundaries strengthen the material without losing ductility as revealed by mechanical tests. Cellular structure can be continuous across the melt pool boundaries, low angle sub-grain boundaries, but not grain boundaries. Based on the above understanding, AM process parameters were adjusted to achieve customized mechanical properties. Comprehensive characterization were carried out to investigate the density, composition, microstructure, phase, magnetic permeability, tensile property, Charpy impact property, and fatigue property of both SLM and EBM SS316L at room temperature and at elevated temperatures (250°C and 400°C). In general, SLM SS316L has better strength while EBM SS316L has better ductility due to the different process conditions. Improved cell connection between melt pools were achieved by rotating 45° scanning direction between each layer compared to rotating 90°. Superior mechanical properties (yield strength 552 MPa and elongation 83%) were achieved in SLM SS316L fabricated with 20 µm layer thickness and tested in the building direction. Y2O3 added oxide dispersed strengthening steel (ODSS) were also prepared by SLM to further improve its performance at elevated temperatures. Slightly improved strength and ductility (yield strength 574 MPa and elongation 90%) were obtained on 0.3%Y2O3-ODSS with evenly dispersed nanoparticles (20 nm). The strength drops slightly  but ductility drops dramatically at elevated temperatures. Fractographic analysis results revealed that the coalescence of nano-voids is hindered at room temperature but not at elevated temperatures. The achieved promising properties in large AM specimens assure its potential application in nuclear fusion. For the first time, ITER first wall panel parts with complex inner pipe structure were successfully fabricated by both SLM and EBM which gives great confidence to application of AM in nuclear industry. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.</p>

There are multiple applications for polymers: our bodies are built of them, plastic bags and boxes used for storage are composed of them, as are the shells for electronics, TVs, computers, clothes etc. Many polymers are cheap, and easy to manufacture and process which make them suitable for disposable systems. The choice of polymer to construct an object will therefore highly influence the properties of the object itself. The focus of this thesis is the application of commonly used polymers to solve some challenges regarding integration of electrodes in electrokinetic devices and 3D printing. The first part of this thesis regards electrokinetic systems and the electrodes’ impact on the system. Electrokinetic systems require Faradaic (electrochemical) reactions at the electrodes to maintain an electric field in an electrolyte. The electrochemical reactions at the electrodes allow electron-to-ion transduction at the electrode-electrolyte interface, necessary to drive a current at the applied potential through the system, which thereby either cause flow (electroosmosis) or separation (electrophoresis). These electrochemical reactions at the electrodes, such as water electrolysis, are usually problematic in analytical systems and systems applied in biology. One solution to reduce the impact of water electrolysis is by replacing metal electrodes with electrochemically active polymers, e.g. poly(3,4-ethylenedioxythiophene) (PEDOT). Paper 1 demonstrates that PEDOT electrodes can replace platinum electrodes in a gel electrophoretic setup. Paper 2 reports an all-plastic, planar, flexible electroosmotic pump which continuously transports water from one side to the other using potentials as low as 0.3 V. This electroosmotic pump was further developed in paper 3, where it was made into a compact and modular setup, compatible with commercial microfluidic devices. We demonstrated that the pump could maintain an alternating flow for at least 96 h, with a sufficient flow of cell medium to keep cells alive for the same period of time. The second part of the thesis describes the use of 3D printers for manufacturing prototypes and the material requirements for 3D printing. Protruding and over-hanging structures are more challenging to print using a 3D printer and usually require supporting material during the printing process. In paper 4, we showed that polyethylene glycol (PEG), in combination with a carbonate-based plasticizer, functions well as a 3D printable sacrificial template material. PEG2000 with between 20 and 30 wt% dimethyl carbonate or propylene carbonate have good shear-thinning rheology, mechanical and chemical stability, and water solubility, which are advantageous for a supporting material used in 3D printing. The advances presented in this thesis have solved some of the challenges regarding electrokinetic systems and prototype manufacturing. Hopefully this will contribute to the development of robust, disposable, low-cost, and autonomous electrokinetic devices. / Polymera material finns överallt omkring oss; våra kroppar är uppbyggda av dem,plastpåsarna och burkarna vi förvarar vår mat av består av dem, våra kläder och andra tingsom finns i vår vardag är uppbyggda av olika typer av polymerer. En polymer är uppbyggd aven repetitiv sekvens av identiska grupper, de kan liknas vid en mönsterrapport vilken är denminsta del som man behöver repetera för att få mönstret. Beroende på hur rapporten ser ut såförändras utseendet av mönstret. Hos en polymer påverkar sammansättningen av denrepetitiva gruppen (rapporten) egenskaperna av materialet och polymerer kan vara allt frånhårda och robusta, till flexibla och elektriskt ledande. Arbetet som presenteras i den häravhandlingen berör hur funktionen av olika system påverkas av att man använder sig avpolymerer istället för konventionella material. Första delen av avhandlingen handlar om integrering av elektronik i system som innehållervätska. När vätskor, laddade partiklar, molekyler och joner rör på sig på grund av ett yttreelektriskt fält, så kallas detta för elektrokinetik. Detta kan användas för att pumpa vätska ikanaler som är mindre än 0.2 mm, genom så kallad elektroosmos, samtidigt kommermolekyler med olika laddning att börja separera, så kallad elektrofores. Elektroosmos användsinom t.ex. analytisk kemi för injektion och transport av vätskor. Elektrofores används inombl.a. rättsvetenskap och molekylärbiologi för att separera makromolekyler, så som DNA ochproteiner, med avseende på deras storlek och laddning. I dessa system använder man sig oftastav metallelektroder. När en spänning läggs till ett par metallelektroder som är i kontakt med vatten kommer denhuvudsakliga reaktionen att vara spjälkning av vatten, så kallad vattenelektrolys. Spjälkningav vatten innebär att det bildas vät-och syrgas samt att pH börjar ändras. Gaserna som bildaskan bryta kopplingen mellan elektroderna och därmed stoppar strömmen, så som sker när mandrar ut sladden för t.ex. en elvisp. Förändringar i pH kan t.ex. påverka biologiska provernegativt, så som proteiners funktion och kan leda till celldöd, men kan också minska flödenaen elektroosmotisk pump kan generera. Det finns flera olika sätt hur man kan hanteravattenelektrolys i system med metallelektroder, så som användning av en pH-buffer. Arbetet iden här avhandlingen visar vad som händer om man ersätter metallelektroder med elektrisktledande plastelektroder. I detta fall har metallelektroderna ersatts av den elektriskt ledandepolymeren PEDOT vilket resulterar i att , där man istället för generera gas och pHviförändringar, så förflyttar man joner mellan elektroden och omgivande lösning. Ledandepolymerer är billiga och enkla att tillverka vilket gör dem lämpliga för engångssystem. förändringar, så förflyttar man joner mellan elektroden och omgivande lösning. Ledandepolymerer är billiga och enkla att tillverka vilket gör dem lämpliga för engångssystem.I den här avhandlingen visas följande exempel där metallelektroder ersatts av ledandeplastelektroder: Gelelektrofores (separation av proteiner i en gel), (se papper 1), tyg som kanpumpa vatten (plan elektroosmotisk pump, se papper 2) och en kompakt pump som inte ärstörre än ett kaffemått, som enkelt kan kopplas till befintliga sprutkopplingar och som kananvändas för att kontrollera flödet över t.ex. celler (se papper 3). Andra delen av avhandlingen handlar om 3D skrivare och hur materialval påverkarutskriften och designen. 3D skrivare är ett bra alternativ för att snabbt och billigt kunnaproducera prototyper och funktionella individanpassade objekt i varierande storlekar.3D skrivare kan beskrivas som en avancerad spritsmaskin där material läggs lager på lager föratt bygga upp det slutgiltiga objektet utifrån en datorgenererade 3D model. Detta förändrarhelt hur man designar objekt och vilka möjliga strukturer och material man kan använda sigav jämfört än då man till exempel använder sig av svarv eller fräs för tillverkning. Det finnsflera olika typer av 3D skrivare, t.ex. smältplastskrivare (den typ som man kan se i flertaletaffärer idag) och den variant som använts i den här avhandlingen, en sprutbaserad. Ensprutbaserad 3D skrivare kan hantera många olika typer av material så länge dessa kan fyllas ien spruta och tryckas ut genom en nål. Det färdiga resultat kan därmed bli mycket olikaberoende på vilka material som använts. Överhängande och utstickande strukturer kan vara komplicerade att skriva ut med en3D skrivare. Utskrift av dessa strukturer kan underlättas genom att man skriver ut en temporärstruktur i ett annat material, ett offermaterial. Offermaterialet fungerar som en mall eller stödtill det slutgiltiga objektet och tas bort (offras) när övriga delar av objektet är klara. I den häravhandlingen beskrivs hur ett offermaterial baserat på polyetylen glykol (PEG, vanligtförekommande i t.ex. schampo och läkemedel) och en mjukgörare kan anpassas för attfungera tillsammans med en sprutbaserad 3D skrivare (se papper 4) för att skriva ut strukturerfrån 0,2 mm och uppåt. Arbetet i den här avhandlingen visar användningen av den ledande polymeren PEDOT i ettelektroforessystem och en elektroosmotisk pump. Detta kan förhoppningsvis underlättautvecklingen av dessa system till att bli mindre, smidigare, snabbare och billigare. Den andradelen presenterar ett vattenlösligt, PEG-baserat material som kan användas som stöd till andramaterial i sprutbaserade 3D utskrifter för att underlätta tillverkningen av 3D utskrivna objekt.

With the dwindling availability of petroleum, focus has shifted to renewable energy sources such as lignocellulosic biomass. Lignocellulosic biomass is composed of three main constituents, lignin, cellulose and hemicellulose. Due to the low value of cellulosic ethanol, utilization of the lignin component is necessary for the realization of an economically sustainable biorefinery model. Once depolymerized, lignin has the potential to replace petroleum-derived molecules used as bulk and specialty aromatic chemicals. Numerous lignin depolymerization strategies focus on cleavage of β-aryl ether linkages, usually at high temperatures and under reductive conditions. Alternatively, selective benzylic oxidation strategies have recently been explored for lignin and lignin models. In this work, heterogeneous catalytic methods using supported base metals and layered-double hydroxides were evaluated for the oxidation of lignin models both before and after benzylic oxidation. Additionally, by studying putative reaction intermediates, insights were gained into the mechanisms of oxidative fragmentation of the model compounds. Generally, it was found that after benzylic oxidation models were more susceptible to oxidative fragmentation. Indeed, several heterogeneous oxidation systems were found to convert lignin models to oxygenated aryl monomers (mainly benzoic acids and phenols) using inexpensive primary oxidants (i.e., hydrogen peroxide and molecular oxygen). Reactions were conducted at relatively mild temperatures and at low oxygen concentrations for the purpose of an easy transition to large-scale experiments. Finally, the catalytic systems that resulted in significant cleavage of lignin models were applied to a Kraft lignin. Oxidation of Kraft lignin resulted a mixture of products for which analytical data and increased solubility are consistent with interunit cleavage within the lignin macromolecule.

One third of world’s total energy is used in production of electricity and one fifth of the total electricity produced in the world is used in lighting. Hence, the materials that have high potential in the field of photovoltaic’s and photoluminescence have recently drawn special attention to meet the ever increasing energy demands. In this thesis, we have studied a few materials that hold tremendous promises in fabricating photovoltaics and photoluminescent devices. Any ferroelectric material is an efficient solar energy converter as it contains an the intrinsic dipolar field which can effectively separate the photo excited electron and hole. We have developed a few materials which possess inherent polarization efficiently absorb over a wide portion of the solar spectrum and hence can find application in the field of photovoltaics. Secondly, we also dealt with semiconductor nonmaterial’s which are technologically very important owing to their improved photoluminescence properties. We tried to improve their light emitting efficiency by engineering crystal structure in nanometer length scales. The thesis deals with such advanced energy materials and is divided in seven chapters. Chapter 1 provides a brief introduction to the fundamental concepts that are relevant in the subsequent chapters. The chapter is started with a brief scenario of current status of energy production and its usage. Next, we have discussed the prospects of ferroelectric materials in photovoltaic devices. This is followed by a brief background on ferroelectricity and related properties which we have studied subsequently. At the end of this chapter a brief overview of photoluminescence properties in semiconductor nonmaterial’s is presented. In this section we have addressed the particular issues that need to be taken care of in order to improve their light emission properties. Chapter 2 describes different experimental and theoretical methods that have been employed to carry out different studies presented in the thesis. Chapter 3 addresses the possibility of employing BaTiO3 (BTO) based composite perovskite oxides as a potent photovoltaic material. It is known that BTO can produce photocurrent upon excitation with suitable light source. However, inability of BTO to absorb sufficient sunlight owing to its near UV band gap prevents to make use of this material in photovoltaic devices. In order to reduce the band gap we have tried to tune the electronic structure at the band edge by doping non-d0 transition metal ions at Ti site. As it is known in the literature an isovalent substitution of Ti4+ stabilizes non-polar phase of BTO we employed a co-doping strategy to substitute tetravalent Ti with equal percentage of a trivalent and a pentavalent metal ion. Keeping in mind off-centering of Ti4+ is primary reason behind the large ferroelectric polarization of BTO, a judicious choice of co-dopant was necessary to minimize reduction of polarization due to replacement of Ti. We have found at least two pairs of co-dopants, namely Mn3+-Nb5+ and Fe3+-Nb5+ which at low doping concentration ( < 10%) effectively reduces the band gap of BTO without affecting its polarization to a large extent. We systematically increase the doping concentration of both the pair of dopants and found Mn3+-Nb5+ pair is more efficient over Fe3+-Nb5+ both in terms of reducing band gap and retaining the polarization of BTO. We have characterized the ferroelectric nature of all the doped compositions with the help of dielectric, polarization and pyroelectric measurements. We have also performed first principle density functional theory (DFT) calculations for an equivalent doped composition and addressed the nature of modulations of electronic structure at the band edges which is responsible for such large reduction of band gap. Chapter 4 deals with composite perovskite materials which posses large tetragonal distortions with reduced optical band gaps. Here we have exploited Cu-Nb and Cu-Ta pair which upon complete substitution of Ti of BTO leads to composite perovskites with enhanced tetragonal distortion of the perovskite lattice. For two resultant compositions, namely BaCu1/3Nb2/3O3 and BaCu 1/3Ta2/3O3 we have characterized the optical and ferroelectric properties. We found though these material possess small band gap (∼ 2 eV), these are not ferroelectric in nature. Results of second harmonic generation measurements and refinement of powder X-ray diffraction both establish Centro symmetric nature of these materials. We infer from these results that presence of large tetragonal distortion is a result of symmetric Jahn-Teller type distortion of Cu2+ and not due to off-centering of any of the metal ions in their MO6 octahedral geometries. In Chapter 5, we have considered the material SrTiO3 (STO) which is stable in cubic paraelectric phase at room temperature. But at the same time this material is considered as an incipient ferroelectric due to presence of an active polar vibrational mode which does not become completely soft even at temperature close to 0 K. While this polar vibrational mode can easily be frozen by making substitution at Sr site, a similar attempt by making substitution at Ti site failed earlier. Keeping in mind Ti is easier to substitute than Sr we employed same co-doping strategy that we have considered in Chapter 3. We found Mn- Nb and Mn-Ta co-dopants at low doping concentration are extremely useful in transforming incipient ferroelectric STO into a dipolar glass. We have characterized the glassy dipolar property of doped STO with the help of tem-perature dependent dielectric response of these material. At the same time we found these co-doped STO possess enhanced static dielectric constant at room temperature with favourable dielectric loss values in comparison to pure STO. We have also ad-dressed the origin of a glassy dipolar state with the help of DFT calculation performed on equivalent doped composition that we have considered for our experiments. In Chapter 6, we have considered another incipient ferroelectric material TiO2 in rutile phase which also possess polar vibrational mode at temperature close to 0 K. A lattice strain along the polar vibrational mode make symmetric non-polar structure unstable with respect to the distorted polar structure. In this context, we found two particular compositions FeTiTaO6 and CrTiTaO6 that are also stable in rutile phases at room temperature but possess similar strain due to presence of larger Fe or Cr and Ta in rutile lattice. Considering the fact these two composite rutile oxides are relaxer ferroelectric in nature, we critically evaluated the effect of the particular kind of strain that these materials introduce in rutile lattice. We also characterized relaxor ferroelectric property and optical band gap of these materials and commented on the potential of these materials in exploiting them in photovoltaic devices. Chapter 7 presents a unique strategy of making use of crystal defects in improving photoluminescent properties of semiconductor nanocrystals. We have shown defects when introduced in nanocrystals in a controlled protected manner efficiently overcome the problem of self absorption which is known to reduce quantum efficiency of emit-ted light. Controlling synthesis conditions we separately prepared CdS nanocrystals with and without intergrowth defects. We characterized the presence of the intergrowth defect with the help of high resolution transmission electron microscope (HRTEM) image. We have also characterized Stokes’ shifted PL emission and ultrafast charge carrier dynamics of these NCs with intergrowth defects. To support these experimental findings we have computed the electronic structures of model nanoclusters possessing similar intergrowth defects that has been observed in HRTEM images. We find that the presence of defects in a nanocluster particularly affect the position of the band edge. However our joint density of state calculation shows that contribution of these defect states to an absorption spectra is negligible. Thus presence of defect states at band edge ensures a Stokes’ shifted emission without affecting the position of absorption. In a separate section of this chapter we have shown apart from intergrowth defects presence of twin boundary also provide similar mid-gap states that can alter its’ optical proper-ties to large extent. In summary, we have studied a few bulk and nano-materials which can show improved photovoltaic and photoluminescence property. We investigated effect of external dopant ions on a classical ferroelectric material BaTiO3 and two incipient ferroelectric materials SrTiO3 and rutile TiO2. We have also shown that efficient defect engineering could be extremely useful in improving photoluminescent property of CdS nanocrystals which is a prototype of II-VI semiconductor nanomaterials. In a separate Appendix Chapter, we have shown an easy and efficient way to suppress coffee ring effect which takes place universally when a drop of colloidal suspension is dried on a solid substrate. We have shown temporary modification of hydropho-bicity of a glass substrate not only can suppress the coffee ring effect but also leaves the particle in a highly ordered self-assembled phase after completion of drying process

This diploma thesis is aimed at the possibilities of the usage of physical activities in chemistry education. The theoretical part of this thesis contains the analysis of RVP ZV and RVP G, especially the content of the movement. This part is also focused on the physical activities, the types and styles of learning, especially on the kinesthetic learning style, and the motivation of pupils. The practical part of this thesis is focused on the finding of usage physical activities by teachers of chemistry. These data are obtained through interviews with chemistry teachers. These teachers also evaluated the created chemistry physical activities, which are presented in the diploma thesis. The chemistry physical activities also includes methodological instructions for users.

Nanomaterials such as graphene oxide and carbon nanotubes, have demonstrated excellent properties for membrane desalination, including decrease of maintenance, increase of flux rate, simple solution casting, and impressive chemical inertness. Here, two projects are studied to investigate nanocarbon based membrane desalination. The first project is to prepare hybrid membranes with amyloid fibrils intercalated with graphene oxide sheets. The addition of protein amyloid fibrils expands the interlayer spacing between graphene oxide nanosheets and introduces additional functional groups in the diffusion pathways, resulting in increase of flux rate and rejection rate for the organic dyes. Amyloid fibrils also provide structural assistance to the hybrid membrane, which supresses cracking and instability of graphene oxide sheets. The second project is to fabricate polymer nanocomposite membranes with carbon nanotubes encapsulated by polymerized surfactants. The designed polymerizable surfactant forms lyotropic liquid crystalline mesophases in an aqueous medium with hexagonal packing of cylindrical micelles. The adsorption of surfactants on the surface of carbon nanotubes allows a stable dispersion of carbon nanotubes encapsulated in the cylindrical micelles, resulting in the ordered structure. After photo-polymerization, the composite membranes display enhanced dye rejection. Both projects have shown promising ways to improve membrane filtration by using nanomaterials.

The state-of-the-art tools for machining metals are primarily based on a metal-ceramic composite(WC-Co) coated with different combinations of carbide, nitride and oxide coatings. Combinations of these coating materials are optimized to withstand specific wear conditions. Oxide coatings are especially desired because of their possible high hot hardness, chemical inertness with respect to the workpiece, and their low friction. This thesis deals with process and coating characterization of new oxide coatings deposited by physical vapor deposition (PVD) techniques, focusing on the Cr-Zr-O and Al-Cr-Si-O systems. The thermal stability of α-Cr0.28Zr0.10O0.61 deposited by reactive radio frequency (RF)-magnetron sputtering at 500 °C was investigated after annealing up to 870 °C. The annealed samples showed transformation of α-(Cr,Zr)2O3 and amorphous ZrOx-rich areas into tetragonal ZrO2 and bcc Cr. The instability of the α-(Cr,Zr)2O3 is surprising and possibly related to the annealing being done under vacuum, facilitating the loss of oxygen. The stabilization of the room temperature metastable tetragonal ZrO2 phase, due to surface energy effects, may prove to be useful for metal cutting applications. The observed phase segregation of α-(Cr,Zr)2O3 and formation of tetragonal ZrO2 with corresponding increase in hardness for this pseudo-binary oxide system also opens up design routes for pseudo-binary oxides with tunable microstructural and mechanical properties. The inherent difficulties of depositing insulating oxide films with PVD, demanding a closed circuit, makes the investigation of process stability an important part of this research. In this context, we investigated the influence of adding small amount of Si in Al-Cr cathode on plasma characteristics ,process parameters, and coating properties. Si was chosen here due to a previous study showing improved erosion behavior of Al-Cr-Si over pure Al-Cr cathode without Si incorporation in the coating. This work shows small improvements in cathode erosion and process stability (lower pressure and cathode voltage) when introducing 5 at % Si in the Al70Cr30-cathode. This also led to fewer droplets at low cathode current and intermediate O2 flow. A larger positive effect on cathode erosion was observed with respect to cleaning the cathode from oxide contamination by increasing cathode current with 50%. However, higher cathode current also resulted in increased amount of droplets in the coating which is undesirable. Through plasma analysis the presence of volatile SiO species could be confirmed but the loss of Si through volatile SiO species was negligible, since the coating composition matched the cathode composition. The positive effect of added Si on the process stability at the cathode surface should be weighed against Si incorporation in the coating. This incorporation may or may not be beneficial for the final application since literature states that Si promotes the metastable γ-phase over the thermodynamically stable α-phase of pure Al2O3, contrary to the effect of Cr, which stabilizes the α-phase.

Organic semiconductors have witnessed a prolific boom for their potential in the manufacturing of lightweight, flexible, and even biocompatible electronics. One of the fields of research that has yet to benefit from organic semiconductors is high temperature electronics. The lightweight nature and robust processability is attractive for applications such as aerospace engineering, which require high temperature stability, but little has been reported on taking such a leap because charge transport is temperature dependent and commonly unstable at elevated temperatures in organics. Historically, mechanistic studies have been bound to low temperature regimes where structural disorders are minimal in most materials. Discussed here is a blending approach to render semiconducting polymer thin films thermally stable in unprecedented operation temperature ranges for organic materials. We found that by utilizing highly rigid host materials, semiconducting polymer domains could be confined, thus improving their molecular and microstructural ordering, and a thermally stable charge transport could be realized up to 220°C. With this blending approach, all-plastic high temperature electronics that are extremely stable could also be demonstrated. In efforts to establish a universal route towards forming thermally stable semiconducting blends, we found that the molecular weight of conjugated polymer plays a crucial role on the miscibility of the blends. Finally, we found that the choice of the host matrix ought to consider the charge trapping nature of the insulator.<br>

Executive summary Today, packaging has gained a significant role in the food industry as well as other industries. Paper substrates that have been coated in some ways are typically used to make packaging. The amount and type of pigment used in the formulation determine whether this coating is a pigment coating or a barrier coating. Critical pigment volume concentration (CPVC) is the optimum spot when the pigments are packed as densely as possible, and the binder fills the air gaps. When the amount of pigment in a coating is less than CPVC, a barrier coating is formed, although when the amount of pigment in the coating is greater than CPVC, a pigment coating is formed. Pigment coating adds optical properties to a package, such as improved printability. And chemical protection is primarily provided for water, water vapour, fats, and gases in the case of the barrier coating. Chemical protection against these substances means, for food packaging, that the shelf life of the product will be extended, among other things. The role of packaging in society is expected to grow as barrier coatings on packaging continue to improve. The use of nanoclay in barrier coatings is investigated in this laboratory study. Two latexes are tested with nanoclay, with latex chosen based on its glass transition temperature (Tg). The hypothesis was that a latex with a higher Tg would have more properties like brittleness and orderly structure in its amorphous structure than the other latex. Latex with a lower Tg, on the other hand, would have more elasticity, be more ductile, and have a lower degree of ordered structure in its amorphous structure. Latex with a higher Tg was referred to as Hard latex and was composed of Styrene-butadiene, while latex with a lower Tg was referred to as Soft latex and was composed of Polyolefin dispersion, although it is unorthodox to call it latex. Previous research has found that the addition of Bentonite nanoclay can improve the mechanical and barrier properties of barrier coatings. Bentonite was therefore chosen as the nanoclay for this study due to having a higher aspect ratio, is flaky and can improve desired properties. The coating was applied as a dispersion coating using a lab-scale rod coater. The substrate for this study was BillerudKorsnäs FibreForm with a grammage of 150 g/m2.In order to find the optimum rod for the coating, three different rods were tested during screening test 1. The rods tested were based on the desired coating weight and thickness, a red rod with a wet film thickness of 12 μm was chosen. The nanoclay content of the latex formulation was investigated to determine the optimal level for improved barrier properties. In screening test 2, the concentrations examined were 2/4/8 w/w% nanoclay in each latex, and 0 w/w% to compare the difference with Hard/Soft latex to see if there are any benefits of nanoclay. For both latexes, the addition of 2/4 w/w% nanoclay resulted in more pinholes as well as a poor water vapour transmission rate and permeability. The results of screening test 2 showed that adding 8 w/w% nanoclay to both latexes improved the water vapour transmission rate, water vapour permeability, and pinholes test when compared to the other concentrations of nanoclay. In the water vapour transmission rate and pinholes test, however, 0 percent nanoclay performed similarly 8 w/w% for each latex formulation. The selected formulation for further study was 8 w/w% nanoclay with Hard/Soft latex.  Water vapour was the most important barrier property to investigate since barrier coatings were intended for food packaging. For the intended food packaging, it was sought that the barrier could be stretched with 3.8/6.7/10.4%-stretch and then characterized by water vapour transmission rate to be able to see the differences before and after stretching. Stretching with tensile tester were performed on a barrier coated FibreForm, first in the machine direction (MD), then in cross-direction (CD). Hydroforming with shaped bubbles was used for the second method of stretching with various bubbles. Stretching in MD + CD, and hydroforming bubbles were done according to the desired %-stretching. Characterization of the coating was done by water vapour transmission rate (WVTR) for all coatings, pinholes test for hydroformed coatings, water vapour permeability (WVP) and scanning electron microscopy (SEM) on tensile-stretched coatings. The performance of Soft latex with an 8 w/w% formulation stretched in MD then CD and characterized by water vapour transmission rate was significantly unchanged despite stretching up to 10.4%. This is thought to be because nanoclay, as the literature suggests, has created a better barrier against water vapour. The mean WVTR of 10.4%-stretching in MD then CD was 5.5 g/m2/day, compared to 5.5 g/m2/day for the unstretched barrier.  SEM images of both stretched and non-stretched coatings show that the dispersion of nanoclay is poor, as there are islands of polymer and nanoclay bulk. The poor dispersion of nanoclay in the matrix was due to the lack of polar groups in the backbone of Soft latex (Polyolefin) and also being hydrophobic, as opposed to Bentonite, which is hydrophilic. Despite poor nanoclay dispersion and a stretch of 10.4% in MD + CD, resulting in reduced barrier thickness, WVP improved from 289 g* /m2/day (pre-stress) to 191 g* /m2/day (10.4%-stretch), giving the impression of some reorientation of nanoclay in the polymer matrix. A crack was also visible in SEM images, near the boundary layer between the barrier and the substrate, on an unstretched coating, which is thought to be caused by the difference in the boundary layer and adhesive forces, that has occurred during drying. Cracks are not visible on the stretched barriers, even though it was expected. With increased stretching of hydroforming substrates coated with Soft latex formulation, the performance of water vapour transmission rate was significantly worse. The reason for this is thought to be that the barrier was damaged during hydroforming due to friction during pressing and shaping, as the hydroforming was done on the barrier side. The pinhole test revealed clearly degraded performance with a large number of pinholes. This could indicate that the barrier has been stretched beyond its capacity or has been damaged. There was no correlation found between stretching in tensile tester and hydroforming.  Hard latex with an 8 w/w% formulation stretched in MD then CD and characterized by water vapour transmission rate could be stated to have significantly improved performance despite stretching up to 10.4%. The mean-WVTR of 10.4%-stretching in MD then CD was 11.3 g/m2/day, compared to 16.4 g/m2/day for the unstretched barrier. According to SEM images, the reason for this is that nanoclay was very well dispersed in the matrix and that there has seemingly been a slight reorientation of nanoclay with increased stretch. Furthermore, SEM images show that the thickness was reduced, yet despite this, mean-WVP improved from 1094 g* /m2/day (pre-stress) to 419 g* /m2/day (10.4%-stretch), indicating reorientation of nanoclay and thus improved stretchability.These SEM images show cracks at the boundary layer between the barrier and the substrate for both unstretched and 10.4%-stretched barriers in the Hard latex formulation. The cracks are seemingly stopped by nanoclay in the matrix, according to the stress concentration effect, where the crack moves around nanoclay and not through nanoclay. Hydroforming of barrier coated Hard latex formulation showed a deterioration of water vapour transmission rate with increased stretching. The mean WVTR of hydroforming with 10.4%-stretching was 30.6 g/m2/day. It is not thought that pressing during hydroforming damaged the Hard latex barrier as much, which can be confirmed by the pinholes test. Pinholes test demonstrated good performance and comparable to an unstretched barrier. Because comparisons between the different polymers were impractical, it was not possible to state if the glass transition temperature was important for the improvement seen by stretching in the tensile tester. But it can be argued that Hard latex has a more structured and rigid structure, allowing for a greater degree of reorientation. Soft latex, on the other hand, has less stiffness and thus less reorientation. The result of this study is that when stretching is done in both tensile testing and hydroforming, 8 w/w% nanoclay (bentonite) with Hard latex (styrene-butadiene) can be used advantageously in FibreForm packaging if stretchability is desired while maintaining barrier properties against water vapor. / Sammanfattning Idag har förpackningar fått en betydande roll i matindustrin såväl som andra industrier. Vid bestrykning på förpackningar och papperssubstrat så är det vanligt med pigment- eller barriärbestrykning. Vid pigmentbestrykning så tillförs optiska egenskaper till förpackningen, såsom exempelvis förbättrad tryckbarhet. Vid barriärbestrykning tillförs huvudsakligen kemisk skydd mot exempelvis vatten, vattenånga, fetter eller gaser, och innebär för matförpackningar bland annat att hållbarheten blir längre för livsmedlet. Genom fortsatt utveckling av barriärbestrykningar på förpackningar så förväntas även förpackningens roll i samhället att bli större. I denna laborativa studie undersöks möjligheterna kring töjbara barriärer på papperssubstrat, med fokus på vattenångaresistans.  De formuleringar som togs fram bestod av en latex med låg glasövergångstemperatur (Tg), kallad Soft latex med implementerad nanolera samt en latex med en Tg kallad Hard latex med implementerad nanolera. Soft latex var en Polyolefin dispersion med Tg -30°C, och Hard latex var en Styren-butadien latex med Tg = 0°C. 8 w/w% nanolera var den halt som bedömdes ge förbättringar i de mekaniska samt barriäregenskaper som eftersöktes för de båda latex. För denna studie valdes Bentonit som nanolera, på grund av dess plana samt dess fjälliga (flaky) struktur.  Töjbarheten hos de framtagna barriärformuleringarna testades med töjning i dragprov först i maskin-riktning (MD) och sedan tvär-riktning (CD) samt töjning med hydroforming, med töjning på 3,8/6,7/10,4% för respektive metod. Efter töjning av respektive metod bestämdes överföringshastigheten av vattenångpermabilitet (WVTR) genom barriären. En jämförelse gjordes mellan töjning i dragprov och hydroforming för att få en ökad förståelse kring WVTR-prestationen beroende på metod av töjning.  Soft latex visade en oförändrad vattenångaresistans efter 10,4%-töjning i dragprovaren. Detta tros bero på att nanoleran försvårar vattenångan att genomträngas trots töjning. Vid elektronmikroskop (SEM) kunde det ses att dispersionen av nanolera med Soft latex inte var bra, och därför var inte förbättringarna lika tydliga. Den sämre dispersionen av nanolera i matrisen beror på att Polyolefin saknar polära grupper i dess ryggrad (backbone) samt är väldigt hydrofobt, till skillnad från Bentonit som är hydrofilt. Trots sämre dispersion av nanolera och en töjning på 10,4% i MD + CD, så förbättrades vattenånga permeabiliteten (WVP).För hydroforming var prestationen av Soft latexformuleringen gällande WVTR dåliga, och vid Pinholes test fanns det uppenbara pinholes.  Hard latex visade en tydlig förbättring av WVTR efter 10,4%-töjning i dragprovaren, som tros bero på en omorientering av nanoleran i polymer matrisen vid töjning, vilket kan bekräftas av elektronmikroskop (SEM) där viss omorientering är synlig. Dessutom sågs en tydlig förbättring i WVP trots en lägre barriärtjocklek.För hydroforming var WVTR-värdena liknande till endast Hard latex och 0% nanolera.  Vid töjning var jämförelser beroende på de olika glasövergångstemperaturerna hos polymererna inte möjlig, och därför inte heller möjligt att konstatera ifall glasövergångstemperaturen var viktig för den förbättring som setts trots töjning i dragprovare. Men det kan hävdas att Hard latex har en mer strukturerad och stel struktur, vilket möjliggör en större grad av omorientering. Soft latex däremot, är mindre styvt och mindre ordnat, därav åstadkoms en mindre omorientering.  Resultaten av denna studie är att när stretching görs i både dragprovning och hydroformning, kan 8 w/w% nanoclay (bentonit) med Hard latex (styren-butadien) vara fördelaktig i FibreForm-förpackning om töjbarhet önskas samtidigt som barriäregenskaperna mot vattenånga bibehålls.

This paper reviews the effects of accelerated aging with increased humidity and temperature on cellulose-based composites. The composites consist of a matrix of plastic reinforced with cellulose fibers. The company Biofiber Tech Sweden AB provided four different composites and a conventional polyolefin as reference. The aim was to examine changes in mechanical properties, chemical composition and appearance after aging, as well as variations between materials. Two different climate conditions were tested, 85% RH and &lt;10% RH, both in 90℃. A climate chamber and an oven were used to create the extreme environmental conditions. To analyze the results, tensile testing and FTIR were performed, and color intensity and density were measured. All samples decreased in color intensity throughout aging, and dark irregularities appeared on some of the samples exposed to high humidity, which may be due to fungal formation. The tensile testing showed a general difference between high and low RH and the toughness showed a tendency to decline with aging in high humidity for many samples. The FTIR measurements also did not show any general trend. To improve the study, it would be desirable to age the material for a longer time and at a higher temperature. Overall, more samples and measurements within each characterisation technique would be needed to achieve more reliable results. Nevertheless, this study hopes to be a starting point for further research on the long-term durability of Biofiber Tech’s composites.