Betulin is a naturally abundant compound in the outer bark of birch and can be easily obtained by solvent extraction. Herein, solutions of betulin were used to treat cellulosic textile fibers and improve their water repellency. Cotton fabrics impregnated in a 7.5 g L-1 solution of betulin in ethanol showed the highest water contact angle of about 153° while the impregnation in a 3.75 g L-1 solution resulted in a close effect. A terephthaloyl chloride-betulin copolymer was synthesized and dissolved in tetrahydrofuran to afford a solution with a concentration of 3.75 g L-1. The cotton fabric impregnated in this solution showed a water contact angle of 150°. Changes in morphology of the cellulose fibers before and after the treatment were observed by scanning electron microscopy, and the water repellency was measured by a standard spray test. The marketing strategy of the potential product, which will be developed based on this technique, was discussed.

Breathable water-repellent garments are common products on the outdoor market. There are many recommendations on how to wash and waterproof your garment in order to make sure that its water-repellence is cared for, but the advice given by different sources is inconsistent. Are expensive products really necessarily or are regular laundry products just as good? What waterproofing agents should one use in order to insure that the water-repellent layer is restored? Four different water-repellent wash-in products were tested on polyester and polyamide fabrics. Seven laundry products and two water-repellent wash-in products were tested on jackets with dendrimer based finishes and untreated polyamide fabrics. The results were evaluated by spray testing according to ISO EN 24920 and sessile drop tests. Not all wash-in products offer good water-repellence on polyamide and polyester fabrics. Two laundry detergents decreased the water-repellence of the jackets. The laundry detergents did not affect the function of wash-in waterproofing agents on the jackets. The water-repellence of one wash-in product was affected by the use of two different detergents on untreated fabric / Program: Textilingenjörsutbildningen

Steel producers use various organic and inorganic coatings to protect cold-rolled steel (CRS) sheets from corrosion during shipment and storage. It is well known that CRS sheets can be protected from corrosion by galvanizing, phosphating, chromating, topcoating with organic, or their combinations. The chromate rinsing is particularly effective for preventing white rusting of galvanized steel. But there is an increasing interest in a replacement for the chromating process because of environmental and health concerns. The objective of the present work is to develop a chrome-free conversion coating for steel sheets. Various carboxylic acids and their salts have been studied for coating phosphated electrogalvanized (EG) steel sheets, including 10-undecenoic acid (UA), oleic acid (OA), and other fatty acids such as stearic acid (SA) and palmitic acid (PA). When they were used alone, or subsequently coated with resin, they could produce a highly hydrophobic surface and improve the corrosion resistance. Thiols such as 1-octadecanethiol (ODT) can form a self-assembled monolayer on metal substrates. This close-packed monolayer could provide an excellent corrosion resistance for EG steel sheets. It was capable of withstanding 50~60 hours of salt spray test (SST) although its thickness was only a few nanometers. The EG steel itself usually started rusting only after 2~4 hours of salt spray. In another coating system, thiols were mixed with a conventional resin to improve the corrosion resistance of EG steel. This new technique gave 100~120 hours of corrosion resistance. When the resin was applied directly on EG steel surface, its corrosion resistance was less than 72 hours. It was shown that further optimization of this technique increased the corrosion resistance to 200 hours and more in the standard SST. / Ph. D.

The purpose of this research is to investigate the mechanical, microstructural and corrosion performance of the ferritic stainless steel coarse powders, used in Metal Injection Molding (MIM) process. Three coarser powders made by Höganäs AB, were examined along with a commercially available fine MIM powder and samples from sheet metal. The studied powders were individually mixed with binders and then injection molded in the shape of dog bone shaped tensile bars. These green samples were then debinded and sintered to examine under different characterization methods. The methods used for examining the samples were tensile test, hardness test, metallography, SEM, chemical analysis, and salt spray test. After a comparative study of these different materials, it turns out that the chemical composition and the process parameters have more effect on materials properties compared to only particle size distribution in studied materials. After this study, 434 coarse powder was preferred upon the PolyMIM 430 fine powder, because of its lower price and same performance as that of PolyMIM 430.

Varaktig vattenavvisning från engelskans Durable Water Repellents (DWR) är en kemi som appliceras på textil för att göra den motståndskraftig mot vätska. En DWR-kemi som visat sig vara till stor belastning för miljön och därför genomgått en utfasning inom industrin är fluorkarboner. Detta har lett till fluorfria alternativ och även modifierade fluorkarboner vilka det finns bristande information kring gällande risker för miljö och hälsa. I och med övergången från fluorerade DWR till de fluorfria alternativen aktualiserades frågan kring hur ”durable”, alltså motståndskraftiga mot tvätt och användning, dessa verkligen är. Detta har resulterat i ett stort utbud av konsumentprodukter för återupplivning av vattenavvisning på beklädnad i hemmamiljö. Dessa konsumentprodukter har benämnts som återimpregneringar i denna studie. Återimpregneringar kan göra att användaren förblir nöjd med beklädnaden och detta minskar i sin tur det textila avfallet. Området är outforskat och industrin vill veta mer om dessa konsumentprodukter inklusive hur det textila materialet påverkas av dem. Studien har utgått från ett kundperspektiv vid val av relevanta parametrar och på ett kreativt sätt översatt dessa till laborativa testmetoder. De parametrar som funnits med i studien har varit vattenavvisning, färgförändring, luftgenomsläpplighet samt känsla vilka har använts för analys och jämförelse mellan åtta stycken fluorfria återimpregneringar. Två etablerade appliceringstekniker, wash-in och spray-on, har undersökts på fyra olika textilier som skulle kunna representera frilufts- samt arbetskläder. Två av textilierna var av polyester och två var av polyamid. Samtliga återimpregneringar gav en ökad vattenavvisande effekt. Resultatet varierade beroende på vilket textilt material och vilken återimpregnering som användes. De övriga testmetoderna, färgförändring, luftgenomsläpplighet och böjstyvhet, visade även de liknande variationer i resultaten. Wash-in och spray-on teknikerna kunde generellt visa på statistiska skillnader. Även produkter med samma varumärke applicerade med wash-in och spray-on teknik visade skilda resultat. De laborativa testmetoderna som valts ut visade sig vara användbara verktyg för utvärdering av återimpregneringar vid textilapplicering.  Utifrån litteraturens rön och denna studies resultat har slutsatsen dragits att konsumentprodukter för återimpregnering av textil har betydande skillnader beroende av vilken DWR-kemi de består av samt textiliens konstruktion och fibersort. Det säkraste fluorfria alternativet ur miljösynpunkt tros av rapportförfattarna vara vax som klassas som en kolväteskemi, men det finns mycket kvar att utforska innan en sådan slutsats kan dras med säkerhet. Denna studie har varit ett inledande steg mot att undersöka återimpregneringar som förhoppningsvis i framtiden kan leda till ett minskat textilt avfall med minsta möjliga miljöbelastning. / The textile industry uses durable water repellents (DWR) to achieve water repellency on textiles. One of these DWR chemistries, fluorocarbons, is an environmental issue and has therefore been phased-out in the industry. This has resulted in a market where both modified fluorocarbons and fluorine-free alternatives are available and there is a lack of information about these DWR regarding health and environmental aspects. Due to the changeover from the fluorinated DWR to the non-fluorinated options, the question was raised about how durable these really are. This resulted in a wide range of do-it-yourself consumer products for the water repellency revival. These consumer products have been referred to as reimpregnations in this study. The purpose of reimpregnations is to give clothing a longer life cycle. The customer remains satisfied with the garment and this in turn reduces the textile waste. The industry wants to know more about these unexplored consumer products, including how the textile material is affected by them. A customer perspective has been the basis for selecting relevant parameters in this study, which has been creatively translated into laboratory test methods. Parameters in this study have been water repellency, color change, air permeability and fabric hand. These have been used for analysis and comparison of eight fluorine-free reimpregnations. The techniques used were wash-in and spray-on and have been investigated on four different textiles representing outdoor clothing and workwear, two made of polyester and two of polyamide. All the reimpregnations showed an increased effect in water repellency. The result varied depending on which textile material and what kind of reimpregnation that was used. The other test methods also showed variation according to these factors. Over all the wash-in and spray-on techniques showed a statistical significance. Products from the same brand applied with wash-in and spray-on techniques also showed different results. The selected laboratory test methods proved to be useful tools for evaluation of reimpregnations in textile applications. Based on the literature combined with the results from this study the conclusion has been made that reimpregnation, of textile materials, has a significant difference between DWR chemistries as well as the construction and fibre type of the textile. The safest fluorine-free option, from an environmental point of view, is believed to be wax, which is classified as a hydrocarbon chemistry, however there is much left to explore before such a conclusion can be made with certainty. This study has been an initial step towards the investigation of reimpregnations, which hopefully in the future can lead to reduced textile waste with as little environmental impact as possible.

Corrosion protection is very significant for metals in modern society from the view of industrial development. This thesis work project involves a research study that is aimed to investigate the effect of corrosion on the mechanical strength and magnetic properties of four no treated or treated Somaloy® component samples (Somaloy®700 1P,  Somaloy®700 3P, Somaloy®700HR 5P and Somaloy®110i 5P) provided by Höganäs AB and laminated steel sheets by salt spray test. The coatings for protection are phosphoric acid coating, sodium silicate coating, DCA-Modified silicone conformal coating and water-borne single coat paint respectively. Then the protective properties are evaluated by Electrochemical Impedance Spectroscopy (EIS) in 0.1 mol/L NaCl solution after 7 days exposure.   From transverse rupture strength (TRS) and hysteresis loop measurements by salt spray test, although the bar samples are treated coating, the corrosion decreases the mechanical strength to a certain extent more or less over time. For the magnetic properties, the corrosive environments hardly influence the magnetic parameters of the no treated or four types of coatings treated Somaloy® components. But the all kinds of magnetic parameters for laminated ring samples have a great variation after salt spray test.   In the EIS measurements, for the no treated samples, the initial corrosion resistance is only several hundred ohms and decreases after 1 hour, 8 hours and 1day exposure, then increases to a certain extent with time due to the corrosion products formed on the surface. For the sodium silicate coating, the initial corrosion resistance is approximately several ten thousands ohms and decreases rapidly only after 1 day exposure to several hundred ohms due to the sodium silicate film dissolves in the electrolyte solution and has no effective protective property. Then the following corrosion process is almost same as the no treated samples. For the water-borne single coat paint, the initial corrosion resistance can reach to several Giga-ohms and decreases over time, but can still stay at  level, indicating that this coating has a very good and effective protective properties.   EIS experiments indicate that water-borne single coat paint has a more effective protection than sodium silicate coating and can apply a better corrosion protection for the Somaloy® components   Key words: corrosion protection, soft magnetic composites, phosphoric acid coating, sodium silicate coating, DCA-Modified silicone conformal coating , water-borne single coat paint, salt spray test, TRS, hysteresis loop, EIS

Influence of atmospheric and chemical environments on metal products leads usually to the corrosion damage. This master´s thesis deals with way to protect metals from corrosion, especially by polysiloxane coatings in combination with coatings containing zinc. Corrosion resistance of created coatings systems is tested by laboratory accelerated tests in corrosion chamber, where the natural atmospheric conditions are simulated. Chemical resistance in selected environments is verified by drop test. Quality characteristics coatings – thickness, adhesion to the underlying material, hardness and stability of the coating colour and gloss are evaluated too.

Organic coatings are extensively used as protective coatings in several industries including the automotive and aircraft industries. The last few years have witnessed an increased interest in improving not only the mechanical properties but also the corrosion protection properties of organic coatings. Among the currently investigated methods of improving the performance of organic coatings is the incorporation of additives in the organic paint matrix. Vapor grown carbon nanofibers (VGCNFs) are a class of carbon fibers that are produced by catalytic dehydrogenation of a hydrocarbon at high temperatures. Depending on the method of synthesis and the post-treatment processes, the diameter of the VGCNFs is normally in the 10-300 nm range. The small size, light weight, high aspect ratio, and unique physical, thermal, mechanical, and electrical properties of VGCNF make it an ideal reinforcing filler in polymer matrix nanocomposites to enhance the mechanical properties of the pure polymeric material in high performance applications in several industries such as the automotive, aircraft, battery, sensors, catalysis, electronics, and sports industries. The main objective of the current investigation was to study the corrosion protection offered by the incorporation of VGCNFs into a commercial alkyd paint matrix applied to the surface of mild steel coupons. The corrosion protection was investigated by immersing samples in air saturated 3% NaCl solution (artificial seawater). The samples were studied by electrochemical impedance spectroscopy (EIS) along with other measurements, including electrochemical (open circuit potential, cyclic voltammetry), chemical (salt spray test), electrical conductivity, and surface analysis (SEM, AFM, optical profilometry, and nanoindentation). The study involved the investigation of the effect of the weight percent (wt %) of the VGCNF as well as the coating film thickness on the corrosion protection performance of the coated steel samples when exposed to the corrosive electrolyte. By way of contrast, the EIS behavior of steel coupons coated with a paint coating incorporating different weight percents of powdered silicon carbide (SiC) particles was also studied. The EIS spectra were used to calculated and graph several corrosion parameters for the investigated systems. At the end, the studied coatings were ranked in order of their anticorrosive properties.