Den additiva tillverkningsindustrin associeras ofta med en hållbar hushållning av resurser. Trots detta har denna industriavfall med stor potential till vidare användning. Detta kandidatexamensarbete undersöker möjligheten att använda Polyamid 12 (PA12) avfall från selektiv lasersintring (SLS) i formen av filament till en annan additiv tillverkningsmetod, friformsframställning. Avfall från olika delar av SLS-processen försågs av life science företaget Cytiva. Olika blandningar av avfallen extruderades till filament. Innan extrudering undersöktes innehåll samt de termiska egenskaperna hos avfallet med hjälp av differentiell skanningskalometri (DSC), termogravimetrisk analys och fourier transform infraröd spektroskopi. Filamenten analyserades med dragprovning, DSC och svepelektronmikroskopi. Rent obearbetat PA12 pulver och ett kommersiellt PA12 filament användes som referenser vid jämförelse. Blandningarna innehållande avfall från SLS-printerns automatiska rengöringsprocess var kontaminerade med glaspartiklar och blev därför spröda och erhöll en skrovlig yta. Dessa filament gick inte att 3D-printa eftersom glaspartiklar ansamlades i munstycket av printern. Flera filament fick en ojäm och liten diameter och kunde därför inte användas i 3D-printern. Ojämn och liten diameter blev resultatet av bekymmer med sensorn som mäter diametern av filamenten. Dessa filament gjordes av granulerade utskrivna prototyper, pulver nära utskrivna delar och silat pulver långt ifrån de utskrivna delarna. Filament gjorda på blandningar innehållande avfall från dammsugaren som används för att rengöra SLS-printern kunde med framgång skrivas ut i 3D-printern. Dessa filament hade en jämn diameter och innehöll inga större kontamineringar. Det är därför genomförbart att tillverka filament av avfall från alla delar av SLS-processen även om inte alla filament kunde 3D-printas. / Additive manufacturing is often associated with sustainable use of resources. However, this industry still has material waste with great potential for further use. This bachelor thesis examines the opportunity of using Polyamide 12 (PA12) waste from Selective laser sintering (SLS) in the form of filaments for another additive manufacturing method, fused filament fabrication. Waste from different parts of the SLS process were provided from the life science company Cytiva. Several blends of the waste were made into filaments. Prior extrusion, the thermal properties and content of the waste were examined with differential scanning calorimetry (DSC), thermogravimetric analysis and fourier transform infrared spectroscopy. The filaments were analyzed by tensile testing, DSC and scanning electron microscopy. Pure virgin powder of PA12 and a commercial PA12 filament were used as a reference for comparison. The blends containing waste from the SLS printer’s automatic blasting was contaminated with glass beads which resulted in brittle filaments with a rough surface. These filaments were not possible to 3D print with due to accumulation of glass beads in the nozzle of the printer. Several filaments got an uneven and small diameter and could therefore not be 3D printed with. The small and uneven diameter was a result of issues with the sensor measuring the diameter. This includes filaments made of granulated printed prototypes, powder close to the printed parts and sieved powder further away from printed parts. The filaments made of blends including waste from the vacuum cleaner used to clean the SLS printer could successfully be used in printing. These filaments had an even diameter and did not contain any larger contaminations. It is therefore possible to make filaments from waste from all parts of the SLS process although not all filaments could be 3D printed.

When slow wear mechanisms are studied it is important to examine slower processes, such as diffusion. Such processes can have a significant impact over time and can cause other phases to form, which can have a large effect on the wear. This thesis has investigated the diffusion that is believed to take place between brass and cemented carbide tools. This was done to further the understanding of the slow atomic wear which if properly understood, could lead to solutions that would increase the lifetime of the tools. The diffusion pairs were made from a tribological contact and then heat treated to speed up the diffusion process. Different temperatures and times were tested, from 400 °C for 3 h to 700 °C for 24 h. The samples were analysed with SEM and EDS both before and after the heat treatment, to see if diffusion had taken place. However, because of many unexpected processes and reactions the analysis could not confirm that diffusion had taken place. The transportation of Cu at the higher temperatures was much faster than expected, and in some samples, Cu could not be detected after the heating. Since the surface was so mobile, the slower diffusion process did not have time to take place. Many improvements for future experiments are suggested to be able to observe the diffusion, such as depositing a thin film or adding more work material.

The market is in great need of more environmentally friendly alternatives to fossil-based composite materials to obtain a more sustainable future. Lignin is the second most common biopolymer and is a byproduct in the pulping and paper industry. Fractionation of lignin has made it possible to receive lignin with narrow dispersity and low molecular weight, which is suitable for further applications. Modification of lignin structure yields new reactive sites that can be tailored for specific needs. Because of the aromatic structure of lignin, it is a promising renewable resource for production of thermosets. In this project Kraft lignin is sequentially solvent-fractionated and modified in an allylation process with allyl chloride. The allylated lignin is reacted with a cross-linking agent and used to impregnate carbon fibre mats. The resin-coated material is then cured at 125 oC to achieve a composite material. The project also encompasses characterization of the chemical structure of lignin in the different fractions. The morphology and adhesive properties of the lignin as well as the carbon fibres and the composite material was investigated. Although the production of composite material from lignin and carbon fibres were accomplished, bubble formation in the resin was a problem for all composite samples that were prepared, whether it was during solvent evaporation or during curing. By performing the addition of resin to carbon fibre mats in multiple steps, where pressure is added after the first applied layer, it is suggested that complete adhesion to the carbon fibre can be achieved, whilst maintaining adequate resin to carbon fibre ratio. / Marknaden är i stort behov av mer miljövänliga alternativ till fossilbaserade kompositmaterial för att kunna erhålla en mer hållbar framtid. Lignin är den näst vanligaste aromatiska biopolymeren och framställs som en biprodukt i pappersindustrin. Fraktionering av lignin har gjort det möjligt att erhålla lignin med låg dispersitet och molekylvikt vilket är lämpligt för vidare applikationer. Modifiering av lignins struktur ger upphov till nya reaktiva grupper som kan anpassas för ens behov. Den aromatiska strukturen som lignin besitter resulterar i en lovande förnybar resurs för produktion av härdplast. I detta projekt är Kraft lignin sekventiellt fraktionerat med lösningsmedel och modifierat med hjälp av en allyleringsprocess i närvaro av allylklorid. Det allylerade ligninet reagerar med en tvärbindare och används vidare för att impregnera kolfiber. De impregnerade kolfibermattorna härdades i ugn vid 125 oC för att erhålla kompositmaterial. Projektet omfattar även karaktärisering av den kemiska strukturen i lignin från de olika fraktionerna. Morfologin och vidhäftningsförmåga av lignin, kolfiber och likaså kompositmaterialet undersöktes. Ett kompositmaterial bestående av kolfiber och lignin erhölls med framgång under projektets gång, dock var bubbelbildning ett stort problem under förångningen av lösningsmedel och även under härdningsprocessen. Addition av harts till kolfibermattorna i flera steg, där tryck är adderat efter det första lagret har blivit applicerat, anses vara en lovande metod för att en hög vidhäftningsgrad ska kunna erhållas. Detta medan ett adekvat förhållande mellan harts och kolfiber upprätthålls.

Multifunctional drug delivery systems incorporated with stimuli-sensitive drug release, magnetic nanoparticles and magnetic resonance (MR) T2 contrast agents is attracting increasing attention recently. In this thesis, works on polymer nanospheres response to temperature change, superparamagnetic iron oxide nanoparticles (SPION)/polymeric composite materials for MR imaging contrast agents are summarized. A “shell-in-shell” polymeric structure has been constructed through a “modified double-emulsion method”. Thermosensitive inner shell is comprised of poly(N-isopropylacrylamide) which undergoes phase transition at body temperature. Such a feature could facilitate drug release at an elevated temperature upon administration. Furthermore, the dual-shell structure is covered by a layer of gold nanoparticles. According to the cytotoxicity tests, the biocompatibility is shown to be enhanced due to the layer of gold. SPION have been prepared using a high temperature decomposition method. Particle growth of SPION is monitored by transmission electron microscope and synchrotron X-ray diffraction. Poly(L,L-lactide)@SPION (PLLA@SPION) composite particles have been prepared through surface-initiated ring-opening polymerization which has been developed in our lab. For biomedical applications, it is essential to transfer the particles to physiological solutions from organic solutions. Phase transfer of SPION has been carried out by utilizing small molecules. Stability at the neutral pH is of large concern for such transfer systems. A novel phase transfer agent, Pluronic F127 (PF127), a triblock copolymer has been applied and the stability of the aqueous PF127@oleic acid (OA)@SPION solution has been greatly enhanced over a broad pH range. Most interestingly, PF127@OA@SPION show remarkable efficacy as T2 contrast agents as indicated by relaxometric measurements compared with commercially available products. / QC 20101115

The global transition to renewable energy sources is placing high demands on the development of effective energy storage methods, the most prevalent being batteries. Dual-ion batteries are a new battery technology that takes advantage of the simultaneous intercalation of both cations and anions. Dual-ion batteries can be made from environmentally friendly materials such as organic compounds or conductive polymers that are made up of highly abundant elements. These often have a lower cell voltage than metal-based batteries, allowing water-based electrolytes to be used without decomposing. This master’s thesis presents the synthesis, and electrochemical testing of a nanofibrous polyaniline cathode. It also presents the synthesis and electrochemical testing of two anodes being and graphene-enhanced polyimide, and perylene tetracarboxylic diimide (PTCDI). Aqueous ammonium sulfate of 1 M or 3 M concentration is used as electrolyte. A novel full-cell dual-ion battery is also constructed using polyaniline and PTCDI as electrodes. The addition of graphene to polyimide results in changes in morphology with decreased pore size and increased surface area for supposed improved reaction kinetics with the electrolyte. The electrochemical testing of this anode is however not successful. The polyaniline cathode has an early charge/discharge capacity of 184.5/85.2 mAh/g that decreases to 40.4/45.8 mAh/g after 100 cycles. The PTCDI anode has an early charge/discharge capacity of 80.2/87.3 mAh/g but cannot be evaluated after a few cycles due to electrolyte decomposition. For this reason, the electrolyte dependence on ammonium sulfate concentration is also investigated. An increase in molarity from 1 M to 3 M leads to increased stability of the electrolyte. The polyaniline//PTCDI full-cell has a voltage of 1.2 V and shows an early charge/discharge capacity of 17.6/11.9 mAh/g that decreases to 9.1/7.2 mAh/g after 100 cycles where the efficiency stabilizes at 80%.

The purpose of this lab was to investigate the printability of cellulose nanofiber/carbon nanotubes, their functions as actuators, and to compare these properties with MXene/nano cellulose gels. Data on MXene/nano cellulose gel was obtained from previous research made by Hamedi labs. Data on carbon nanotubes were collected through experiments evaluating different concentrations and sonication times to yield a gel with high conductivity and viscosity. While it was concluded that both gels could be printed into 2D or 3D shapes, the latter failed to maintain its structure over time due to issues with drying. However, it was found that only 2D MXene/CNF could be used as a reversible actuator. / Syftet med laborationen var att undersöka 3D skrivningsförmågan för nanocellulosa/ kolnanorör samt samt deras förmåga att fungera att svälla elektroniskt. Vidare jämfördes dessa egenskaper med MXene/nanocellulosageler. Data på MXene/nanocellulosa insamlades från tidigare experiment gjorda av Hamedi labs. Data på kolnanorör insamlades genom en rad experiment, vilka utvärderade olika koncentrationer och sonikeringstider för att producera geler med hög konduktivitet och viskositet. Slutsatsen blev att båda gelerna kunde 3D printas, men endast MXene/nanocellulosageler kunde användas för elektronisk svällning och avsvällning. Inga geler kunde göras till 3D strukturer.

In this study a sample of particles in a size region of 0.05-10 μm were run through a centrifugation process with the ambition to make it monodisperse. The product requirements were stated as follows, particles within the size range of 2 to 3.8 μm should be isolated and separated from the sample with a D90/D10 < 1.4 where the D90/D50/D10 values should be approximately 3.8 μm/2.5 μm/2 μm. It was found that two layers of sucrose with a 50/50 volume distribution of 45w% sucrose solution and 60w% sucrose solution respectively, was the most efficient density gradient arrangement for separation of this particular sample. The optimal time and RPM combination was found to be 5 min 3000 RPM with a fast acceleration and slower deceleration, ratio 9:6. Two centrifugation rounds on the same sample improved D90/D10 drastically. The effect of centrifugation rounds on D90/D10 was not investigated further than 3 rounds, however this would be a good starting point for further studies. The upscaled test runs indicated a positive result, i.e. the yields with respect to both mass and purity were reproducible. It is worth mentioning that the upscale was only in the volume, sample load volume and surface area factors. The gradient height or particle travel distance remained the same.

Anthropogenic emission of greenhouse gases has long been suspected to contribute to global warming and climate change. Most greenhouse gases are emitted in a mixture, so efficient methods and materials to separate and capture the gases are in demand in order to reduce emissions. A promising material group for this purpose is metal-organic frameworks (MOFs). This class of material have the ability to selectively adsorb green house gases due to its high porosity and high surface area. Zeolitic imidazolate frameworks (ZIFs) are a subclass of MOFs that are topologically similar to zeolites and are known for their good chemical and thermal stability.   The aim of this project was to investigate if the greenhouse gas (i.e. CO2 and SF6) capture performance of ZIFs could be improved and tuned using a mixed-linker approach with seven different imidazolate-based organic linkers of different sizes or with various functional groups. As well as to investigate the processability of MOFs using 3D printing. ZIFs composed of different ratios of 2-methylimidazolate as base linker and a second linker of imidazolate, benzimidazolate, 2-aminobenzimidazolate, 5,6-dimethylbenzimidazolate, and 4,5-dichloroimidazolate were succesfully made. The materials were all found to be crystalline, however, mixed-linker ZIFs containing 2-aminobenzimidazole, 5,6-dimethylbenzimidazole and dichloroimidazole were observed to contain more than a single phase. All samples showed to be somewhat porous towards CO2 and SF6, and there seem to be a trend where a low % of a bulkier linker (eg. bIm, ambIm) resulted in a higher uptake of SF6 whereas a high % resulted in a higher uptake of CO2. For dcIm it was the other way around, a low % showed a higher uptake for CO2  whereas a high % showed a higher uptake for SF6. For CO2, the ZIF containing 80% benzimidazolate showed the highest uptake of 9.81 wt%. For SF6, the 25% 4,5-dichloroimidazolate showed the highest uptake of 17.73 wt%. Furthermore, direct ink writing (DIW) 3D printing was also successfully utilized to process and structure a Mn-based MOF using carbopol as binder. The printed structure was found to have similar properties to the pristine MOF in regards to crystallinity and porosity.

Fem metoder har använts för att modifiera barrvedslignin med syftet att öka reaktiviteten av ligninet mot epoxidgrupper. Ligninprover analyserades med NMR och FTIR medan reaktivitet var mätt genom reometri. Metoder som ökade mängden karboxylsyragrupper på ligninet minskade ligninets reaktivitet. Modifikation av lignin med resorcinol minskade reaktiviteten medan modifikation med fenol ökade reaktivitet mot epoxidgrupper. / Five different methods were used to modify softwood kraft lignin with the goal of increasing the reactivity of lignin towards epoxide groups. Lignin samples were characterized with NMR and FTIR while reactivity was measured through rheometry. Methods that increased carboxylic acid content in lignin decreased reactivity. Lignin modification with resorcinol decreased reactivity while lignin modified with phenol increased reactivity.

The increasing energy demand requires a transition from fossil fuels to renewable resources. Lithium-ion batteries (LIBs) offer a promising solution as efficient energy storage devices. However, the aluminum current collector (CC) in LIBs is susceptible to anodic dissolution above 3 V vs. Li+/Li in commercial carbonate liquid electrolytes, compromising the battery performance. In this study, various approaches were explored to mitigate anodic dissolution in LiFSI EC:DEC at high voltages of the aluminum CC in LIBs, employing cyclic voltammetry (CV) and scanning electron microscopy (SEM). It was found that boiling the Al foil in water in an air atmosphere to increase the thickness of the surface Al2O3 layer improved the anodic stability and offered enhanced protection against proton attack (due to the oxidation of the carbonate solvent at high voltage). However, increasing the LiFSI electrolyte concentration to 2 M did not increase the anodic stability due to the absence of a passivating AlF3 layer. Notably, in 4 M LiFSI, impurity-induced high F- concentration facilitated the formation of a passivating AlF3 layer, resulting in improved anodic stability. Moreover, specific volume ratios of LiFSI EC:DEC and 1 M LiPF6 EC:DEC (1:1) (LP40) yielded the F- concentration necessary for forming a passivating AlF3 layer and significantly enhanced the anodic stability. On the other hand, carbon-coating the Al foil did not show significant improvements regarding the anodic stability. It was found that the corrosion was time-dependent at a low scan rate, a drastic anodic dissolution of the aluminum was seen at higher temperatures, and the corrosion also became more pronounced. At room temperature, carbon-coated Al foils exhibited increased stability.