Superacidic mesoporous materials containing covalently embedded PTA were synthesized by sol-gel method. Tetraethyl orthosilicate (TEOS) and phosphotungstic acid (PTA) were used as precursors in the synthesis, ionic and nonionic surfactants were used as pore-forming agents, the reaction proceeded in acidic media. TEM images revealed mesoporous structure with embedded PTA clusters. FT-IR spectra of obtained materials contained characteristic bands of PTA at 957 cm-1. Synthesized catalysts had high BET surface area and high concentration of acidic sites. Alkylation of 1,3,5-trimethylbenzene by 1-decene demonstrated high catalytic activity. The catalyst obtained with Pluronic P123 as a template was the most effective and resulted in highest conversion of 1-decene into alkylated products. Covalent embedding of PTA clusters in addition to thermal and chemical stability of synthesized catalysts enabled their recyclability. Catalysts remained active during subsequent cycles of alkylation.

The layer-by-layer (LbL) technique was used to modify the surface of cellulose fibers by consecutive adsorption of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) followed by a final adsorbed layer of anionic paraffin wax colloids. Paper hand sheets made from the modified fibers were found to be highly hydrophobic with a contact angle of 150°. In addition to the significantly increased hydrophobicity, the sheets showed improved mechanical properties, such as a higher tensile strength. Heat treatment of the prepared sheets further enhanced both the mechanical properties and the hydrophobicity. These results demonstrate the flexibility and robustness of the LbL technique, which allows us to combine the known adhesive effect of PAH/PAA LbL films with the functionality of wax nanoparticles, creating a stronger and highly hydrophobic paper. It was further observed that LbL modified sheets without wax also displayed increased hydrophobicity when heat treated. The mechanism was studied through model experiments where LbL films of PAH/PAA were assembled on flat non-porous model cellulose surfaces. Contact angle measurements showed the same trend due to heat treatment of the model films, although, the absolute value of the contact angles were smaller. Analysis using the highly interfacial sensitive vibrational sum frequency spectroscopy technique showed an enrichment of CH3 groups (from the polymer chain ends) at the solid/air interface. These results indicate that during the heat treatment, a reorientation of polymer chains occurs to minimize the surface energy of the LbL film. In the second part of this work, the adhesive interactions between the main constituents of wood fibers were studied using high-resolution measuring techniques and well-defined model films of cellulose, hemicellulose and lignin. Successful surface modification of polydimethylsiloxane (PDMS) caps, needed in the Johnson-Kendall-Roberts (JKR) measuring methodology, by LbL deposition of nanofibrillated cellulose (NFC) and poly(ethylene imine) (PEI) allowed for the first known all-wood biopolymer JKR measurements of the adhesion between cellulose/cellulose, cellulose/lignin and the cellulose/glucomannan surfaces. The work of adhesion on loading and the adhesion hysteresis were similar for all three systems, suggesting that adhesion between the different wood biopolymers does not differ greatly. / <p>QC 20120314</p>

Avzinkningshärdiga och blyfria mässingslegeringar används i stor utsträckning för att ersätta blyinnehållande mässingslegeringar som används för dricksvattensapplikationer. På grund av det begränsade antalet korrosionsstudier av dessa legeringar är syftet med denna studie att belysa hur vattensammansättning, temperatur och exponeringstid kan påverka legeringarnas korrosionsegenskaper. Tre avzinkningshärdiga mässingslegeringar studerades i kranvatten; två blyfria mässingslegeringar (CW511L och CW724R) och en blyinnehållande mässingslegering (CW602N) som betraktades som ett referensmaterial. En kombination av elektrokemiska, mikroskopiska och ytanalystekniker användes för att utforska korrosionstyp, mekanismer samt korrosionshastighet. Även om samtliga legeringar visade godkända egenskaper i avzinkningstestet enligt ISO 6509-1:2014 var målet att bedöma deras korrosionsbeteende i kranvatten. Vattenkemin justerades för att undersöka effekten av pH, kloridkoncentration och alkalinitet hos de tre mässingslegeringarna under kortvarig exponeringstid (24 timmar). Vattnets korrosivitet varierade beroende på mässingslegeringens sammansättning. Det visade sig att CW511L var känsligare för höga kloridkoncentrationer (44.7 mg/L) och hög alkalinitet (310 mg/L) än för lågt pH (6.9). Det motsatta observerades dock för både CW724R och CW602N. Testvattnets aggressivitet påverkades också av temperaturen när den ökades från 22 °C till 50 °C under exponering i 24 timmar. Medan ingen tydlig avzinkning upptäcktes observerades en kombination av både allmän och lokal korrosion i varierande utsträckning mellan de olika legeringarna. Initieringen av det lokala korrosionsangreppet varierade både med testvattnets kemi och med legeringssammansättningen. Medan CW724R och CW602N bägge uppvisade hög känslighet för lokal korrosion i vattnet med högst pH (8.2), var CW511L mer känslig i det vatten med lågt pH (6.9) vid 50 °C. Effekten av exponeringstid undersöktes i vattnet med högst pH (8.2) för de tre mässingslegeringarna upp till 72 dagar. Korrosionshastigheten baserad på viktminskning visade en förväntad hög korrosionshastighet som minskade med kontinuerlig exponeringstid, vilket ledde till en låg korrosionshastighet för alla tre mässingslegeringarna efter 72 dagar. De blyfria mässingslegeringar uppvisade ur detta perspektiv goda korrosionsegenskaper som är konkurrenskraftiga med mässing som innehåller bly. / Dezincification resistant (DZR) and lead-free brass alloys continue to be widely applied replacing lead containing brasses in the drinking water sector. Due to the limited number of corrosion studies of these alloys in tap water, the present thesis was initiated with the aim to understand how the water type, its temperature and exposure duration can affect the corrosion behavior. Three DZR brass alloys were studied in order to evaluate their corrosion behavior in tap water of varying characteristics. The alloys included were two lead-free brasses (CW511L and CW724R) and a leaded brass alloy (CW602N) considered as a reference material. A combination of electrochemical, microscopic and surface analytical techniques were adopted to explore the corrosion form, mechanisms and corrosion rate. While these alloys passed the dezincification test as per ISO 6509-1:2014, the aim was to assess their corrosion performance in tap water. The influence of water chemistry parameters including pH, chloride concentration and alkalinity on the corrosion resistance of the three DZR alloys was investigated in short-term exposures (24 h). Depending on the brass alloy, the corrosivity of the test waters varied. The results show grade CW511L to be more sensitive in tap water of higher chloride concentration (44.7 mg/L) and alkalinity (310 mg/L) compared with low pH (6.9). However, opposite results were obtained for both CW724R and CW602N. The corrosivity of the test water was also affected by the temperature when increased from 22°C to 50°C during 24 h of immersion. While no dezincification features were observed on the surfaces, a combination of general and localized corrosion was observed to a largely variable extent between the alloys. The extent of initiation of localized corrosion varied with test water and alloy composition. While CW724R and CW602N showed similar high susceptibility to localized corrosion in the alkaline (pH 8.2) tap water, CW511L was more prone to pitting corrosion in tap water of low pH (6.9). The effect of exposure duration was explored in the alkaline test water for the three brasses up to 72 days. Corrosion rates based on weight loss showed an expected initial high corrosion rate which declined with continuous immersion, leading to low and similar corrosion rates for all three brass alloys after 72 days. Thus, at given test conditions, the lead-free brasses showed good corrosion behavior being competitive to the performance of lead containing brass. Therefore, lead-free brass alloys are good candidates to substitute lead-containing brasses in tap water applications.

Metal organic frameworks (MOFs) is a quite recently discovered porous material group which shows potential in many different areas. One of these areas is carbon capture; the framework structure of the porous materials allows gas molecules to adsorb to the surface of the pores. MOFs are conventionally synthesised at high temperatures and with hazardous solvents. The goal of this projectwas to synthesise highly porous MOFs at room temperature with water as the main solvent, using environmentally friendly and non-hazardous precursors. As well as the room temperature synthesis, conventional synthesis methods were used with the same precursors as comparison. The materials were characterised with X-ray diffraction, thermogravimetrical methods and IR-spectroscopy. To assess the porosity of the materials, gas adsorption evaluation was performed with CO2, N2, SF6, and CH4 at 20⁰C. In the end, three novel porous magnesium-based materials and one zirconium-based material were successfully synthesised. One of the magnesium-based materials showed a moderately high CO2 adsorption (2.38mmol/g), and could be synthesised at room temperature. The zirconium-based material showed a remarkably high selectivity (17.7) for SF6 over N2 and a high surface area (550m2/g)

This diploma work was done at Seco Tools AB (SECO) in Fagersta and aimed to evaluate the possibility to model the relationship between deposition data, deposition properties and, cutting performance of a (Ti,Al)N coating on cutting inserts by applying the Multivariate Data Analysis (MVDA) modeling technique Partial Least Squares Projection to Latent Structures Modeling (PLS). Cathodic Arc Deposition (Arc-PVD) was the PVD technique focused on this study. The deposition technique that was focused on in this study was Cathodic Arc Deposition (Arc-PVD). For this purpose, two series of Arc-PVD coatings were manufactured. The first series aimed to generate a supervised explorative model for the deposition process. The second manufactured series was aimed to generate a batch-to-batch variation model of a deposition process. In the first supervised explorative model, the deposition parameters were set by a Design of Experiment (DOE) setup using a quarter factorial design with resolution III. In the second batch-to-batch model, the non-fixed deposition parameters and the cathode wear were monitored, and all other parameters were kept the same for every run. The results demonstrate good possibilities to model Arc-PVD coating properties and its performance in metal cutting with respect to the applied deposition parameters. The supervised explorative model confirmed previously established relationships, while the batch-to-batch model shows that variations between batches could be related to the wear of the cathode. This wear was shown to have a negative influence on the properties of the deposited coating.

Nanotechnology as a field has the potential to answer some of the major challenges that mankind faces in regards to environmental sustainability, energy generation and health care. Though, solutions to these concerns can not necessarily rely on our current knowhow. Instead, it is reasonable to expect that humanity must adapt and learn to develop new materials and methods to overcome the adversities that we are facing. This master thesis has involved developing novel materials, serving as a small step in the continuous march towards a bright future where this is possible. More specifically, this work sought to combine mesoporous magnesium carbonate with various metal-organic frameworks to utilize the beneficial aspects from each of these constituents. The ambition was that these could be joined to render combined micro-/mesoporous core-shell structures, with high surface areas and many active sites whilst maintaining a good permeability. Numerous different synthesis routes were developed and explored in the pursuit of viable routes to design novel materials with potential future applications within for instance drug delivery, water harvesting from air and gas adsorption. Coreshell structures of the hydrophilic mesoporous magnesium carbonate covered with the hydrophobic zeolitic imidazole framework ZIF-8 was successfully synthesized for the first time, and practical studies demonstrated a dramatically enhanced water stability, which is perceived to have an impact on further research on these materials. ZIF-67 was also combined with mesoporous magnesium carbonate in a similar manner. Further, Mg-MOF-74 was grown directly from mesoporous magnesium carbonate, where the latter acted as a partially self-sacrificing template, with the aim of rendering a porous hierarchical structure with contributions from the micro- and mesoporous ranges. The outcomes of all these syntheses were characterized using several analyzing methods such as scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and nitrogen sorption analysis.

High power impulse magnetron sputtering has shown a lot of promise as a way of depositing photocatalytic thin films of titanium dioxide at low temperatures, however, the films deposited are often amorphous and display uncertain photocatalytic abilities. This thesis explores the deposition and characterization of photocatalytic thin films deposited with high power impulse magnetron sputtering.  Multiple films were deposited with reactive sputtering in both the oxide and metal mode of operations at different temperatures, duty cycles and substrate biases. The crystal structure, microstructure and photocatalytic activity of the samples were then characterized in order to correlate to each other as well as the growth conditions. Crystallinities were determined via a combined use of gracing incidence x-ray diffraction and Raman spectroscopy, microstructures were explored in cross-sectional images taken using scanning electron microscopy and the photocatalytic ability was measured by quantifying the rate constant during degradation of stearic acid while under UV-illumination.  It was found that the crystal structure of the sputtered films was influenced by the deposition mode used: oxide mode depositions yielded an anatase structure while metal mode depositions resulted in rutile or mixed structures. The only crystalline films were formed with substrate heating, the application of bias was found to correlate with the formation of more rutile and the most crystalline films were deposited with a higher duty cycle.  Photocatalytic films were successfully deposited at room temperature, even though they were amorphous. Interestingly, the anatase samples were not found to be the most reactive, instead it was found that the crystal structure only displayed a weak correlation to the reactivity of the films. The findings in this work suggest that the reactivity was also heavily influenced by the surface roughness of the samples as well as their microstructures.

<p>  </p> <p>Organic semiconductors have been considered a promising candidate to replace Silicon-based inorganic semiconductors in our electronics due to their lightweight, high flexibility, and solution processability. Recently, conjugated polymers were shown to be functional at up to 200°C, expanding organic semiconductors application territory into high-temperature electronics, which sorely depends on wide-bandgap semiconductors. To push the operational temperature boundary of polymer transistors even further than 200°C, our understanding of temperature impacts on the materials and charge transport mechanism in such harsh conditions needs to be improved. Here, we study the high temperature effect on polymer transistors from two main directions: via molecular design and via device engineering. First, via sidechain design, we explored the impact of close π-π packing on the thermal stability of semiconducting polymers. We discovered that maintaining close π-π packing can lead to lower chain distortion, thus improving the polymer transistors' operational stability at high temperatures. Then we study the impact from device factor, specifically contact resistance in device behavior at extreme conditions. We found that the contact area is more susceptible to high temperatures than other regions in the channels and is the main reason for the degraded performance. We then propose a facile method to minimize the contact problem, to achieve stable devices at above 200°C. And last, we proposed a simple method to attain quasi-temperature independent charge transport in polymer transistors from room temperature to 140°C by simply applying a prolonged bias gate voltage before heating. This research expands our knowledge on charge transport in conjugated polymers at high temperatures and provides a guide to make conjugated polymer transistors for extreme conditions in the future.</p>

<p> Cellulose-based materials have been attracting significant attention in recent years for their potential as renewable and biodegradable materials. Cellulose nanofibrils (CNFs) in particular are readily attainable from woody biomass in high purity and without harsh chemical processes. These CNFs can undergo chemical surface modifications after a simple workup, imbuing them with new attributes that differ from their naturally paper-like structure and properties. In this research, CNFs are modified with oleic acid—another common biomass found in high concentrations in some vegetable oils—which transforms the naturally hydrophilic cellulose into a superhydrophobic material. This transformation can be carried out using solventless mechanochemistry and worked up in ethanol, supporting a green process from start to finish.</p> <p><br></p> <p>Since cellulose contains many free, exposed hydroxyl groups, carboxylic acids can be condensed onto exposed hydroxyls to form esters. In this research, we focus specifically on the oleic acid moiety because its internal alkene has potential for further reactivity. Here we explore methods to introduce crosslinks into esterified CNF (eCNF) for structural and mechanical reinforcement between fibrils. Several methods are attempted, including methods involving thiolene chemistry and epoxide ring opening.</p> <p><br></p> <p>Additionally, efforts have been made to develop a method to disperse eCNF materials in ethyl acetate for deposition by spray coating. Dispersions of eCNF in ethyl acetate are sufficiently stable to enable deposition using simple airbrushing tools. The eCNF coatings are homogenous, superhydrophobic, and have good adhesion to a wide variety of surfaces. </p>

Cement is produced in three main steps: grinding of a mixture of raw materials, sintering of the raw meal to form clinker, and grinding and mixing of clinker, gypsum and additives to make cement. Slag from steel manufacturing can be used to replace some of the raw material, but since slag is a carrier of some unwanted compounds, problems arise. Excess sulphur circulating in the system during clinker production can cause various problems such as clogging. In this report, the circulation of sulphur and other volatile compounds as well as the composition of gaseous and solid materials in the cyclone tower has been studied using old data from 2014 and new measurements. No sulphuric gases were found in the cyclones, so it was concluded that most of the sulphur condenses at the bypass at the inlet to the cyclone closest to the kiln. Condensation is assumed to occur early in the pre-heating tower because of air leaking in. Sulphur balances from 2014 and 2020 showed that usage of slag increases the amount of sulphur that circulates in the system and that the critical amount has been exceeded as of the measurements taken 2020. It is recommended that further measurements are performed, such as qualitative analysis of the solid material to distinguish the different sulphuric compounds, as well as more experiments with varied parameters such as the amount of slag and kiln fuel used.