This work describes how a fatty acid methyl ester (FAME) derived from a vegetable oil can be introduced as reactive diluent in a solvent-borne thermally cured coil-coating system. The evaluated reactive diluent, rape seed methyl ester (RME), has been evaluated both in a fully formulated clear coat system and via model studies. A reactive diluent is a compound that acts as a solvent in the liquid paint, lowering the viscosity, and chemically reacts into the final film during cure. Introduction of a reactive diluent derived from vegetable oil give a more environmental compliant coating since a renewable material is incorporated in the coating and the amount of traditional solvent can be decreased. These positive environmental factors have increased the industrial interest. The fully formulated clear coat studies describes how addition of reactive diluent affects rheological properties of the wet paint, film formation, incorporation, and final film properties in a hydroxyl-functional polyester/melamine coil-coating system. The coating were cured under industrial coil-coating cure conditions and analyzed with Raman, carbon-14 dating, extraction, dynamic mechanical analysis, and visually observed. Viscosity measurement of the wet paint show that RME works as a diluent. RME increase the mobility in the system enhancing the film formation process and occurrence of defect-free films. The incorporation of RME could not be confirmed by Raman analysis. However, carbon-14 dating did indicate the presence of RME that could not be extracted from the films. The appearance and mechanical properties of the films were also significantly affected by addition of RME. Dynamic mechanical analysis of the free standing films showed that the final film properties were affected by oven temperature, choice of co-solvent, and flash-off period. Model studies were performed to further clarify how RME chemically can react through transesterification with the hydroxyl-groups of the polyester. RME and its two main components methyl oleate and methyl linoleate were reacted with primary alcohols with and without tertiary hydrogen both under low temperature (110, 130, 150, 170°C) and industrial cure conditions. The transesterification reaction was monitored with 1H-NMR and real time IR. Evaporation and side reactions, e.g. oxidation, are competing factors with the transesterification reaction. The fatty acid structure affects the conversion as a higher amount of unsaturations triggers higher degree of oxidation. The study also showed that reaction time and temperature affects the transesterification conversion, degree of side reactions, and catalyst choice. / QC 20101117

Combined microwave assisted extraction/degradation of technical lignin in green solvents was successfully employed to generate polyphenolic oligomers with lower Mw than the starting material. For Lignoboost, the highest liquid yield (65 %) was obtained in 20 min at 160 °C using ethanol as solvent. This is an increase in ethanol soluble yield with 38 % compared to solvent extraction. The highest yield for Lignosulfonate was obtained with methanol as solvent, at 160 °C for 20 min. Obtained liquid fractions were analysed by SEC, FT-IR, DSC, TGA, 31P-NMR and 2D-HSQC NMR in order to explain the mechanism of the increased yield, and to study the structural changes after microwave extraction/degradation. 2D-NMR indicates cleavage of β-O-4 inter-unit linkages, but also that some modification around the bond could take place. Lignin based thermosets were synthesised employing the polyesterification between lignin, citric acid and poly(ethylene glycol) (PEG). It was concluded that introduction of PEG into the system was crucial for a homogenous thermoset synthesis with a high gel content. From TGA analysis it could be concluded that the thermoset based on original Lignoboost had a lower thermal stability than the counterparts prepared from lower molecular weight fractions. This implies that the esterification reaction between original Lignoboost and the other co-monomers is obstruct by sterically hindrance, which means that pre-conditioning is positive for the final material properties. / I denna studie utnyttjades en mikrovågsbaserad teknik, för att framgångsrikt extrahera och bryta ner lignin till polyfunktionella oligomerer med lägre molekylvikt än ursprungsmaterialet. Både lignin extraherat genom sulfat- och sulfitprocessen, d.v.s. kraft lignin (Lignoboost) och lignosulfonat, undersöktes. Det högsta lösliga utbytet för Lignoboost (67 %) kunde uppnås efter 20 min vid 160 °C genom att använda etanol som lösningsmedel, vilket är en ökning med 38 % jämfört med enbart extraktion i etanol. Under samma förhållanden uppnåddes även det högsta lösliga utbytet för Lignosulfonat, fast genom att använda metanol som lösningsmedel. De erhållna lösliga fraktionerna analyserades med hjälp av SEC, FT-IR, DSC, TGA, 31P-NMR samt 2D-HSQC NMR, med syftet att förklara ökning i lösligt utbyte samt studera eventuella strukturella förändringar efter bearbetning i mikrovågsugnen. Resultat från 2D-NMR indikerar på nedbrytning av β-O-4 bindningar, men även på att modifikationer kring bindningen kan ha uppkommit. Tvärbundna, ligninbaserade material syntetiserades genom att nyttja polykondensationsreaktionen mellan lignin, citronsyra och polyetylenglykol (PEG), vilket resulterade i esterbindningar. Det var möjligt att dra slutsatsen att introducering av PEG in i systemet var avgörande för att nå homogena material med hög andel tvärbindningar. Genom TGA analyser kunde det fastslås att tvärbundna material baserade obehandlad Lignoboost hade lägre termisk stabilitet än dess motsvarigheter baserade på fraktioner med lägre molekylvikt. Detta tyder på att esterreaktionen mellan obearbetad Lignoboost och de två andra monomererna försvåras genom steriskhindring, vilket innebär att bearbetning av ligninet medför positiva effekter på egenskaperna hos det slutgiltiga materialet.

The innovative technology behind production of strong biofilaments involves the process of spinning filaments from nanoparticles extracted from wood. These nanoparticles are called cellulose nanofibrils (CNFs). The spun filaments can have high mechanical properties, rivaling many other plant based materials, and could be an environmentally friendly replacement for many materials in the future such as fabrics and composites. Before mass production might be possible, the optimal dispersion properties must be determined for the intended use, with regard to concentration, method of oxidation (TEMPO-oxidation or carboxymethylation) and pretreatment through sonication and centrifugation. In this bachelor’s thesis attributes of spun filaments were investigated in order to find a correlation between mechanical properties and the effects of concentration, method of oxidation as well as sonication and centrifugation of the dispersions. The mechanical properties were also compared to the fibrils’ ability to entangle and align during flow-focusing. A variety of analytical methods: flow-stop, tensile testing, scanning electron microscopy (SEM) and wide angle X-ray scattering (WAXS) were implemented for the dispersions and filaments. The results from this study show that flow-stop analysis could be used to determine which CNF dispersions are spinnable and which are non-spinnable, along with which spinnable dispersion would yield the strongest filament. It was also concluded that crystallinity of fibrils affects the mechanical properties of filaments and that TCNFs are generally more crystalline than CMCs. Pretreatment through sonication and centrifugation seems to have a negative impact on spinnability and sonication in combination with low concentration seems to lead to non-spinnable conditions. On the other hand, sonicated dispersions seem to yield a greater number of samples without aggregates than non-sonicated ones. Aggregates, however, seem to only affect ultimate stress out of the measured mechanical properties. Furthermore, concentration and viscosity affect spinnability and CMC dispersions seem to yield thicker filaments than TCNF dispersions. However, due to lack of statistically validated data any definitive conclusions could not be drawn.

vardagligen världen över. Deras användningsområden påverkas ofta genom att blanda dem med förstärkningsmaterial för att bilda kompositer. En sådan komposit är blandningen av polypropylen (PP) och glasfiber. Framställningen av PP och glasfiber orsakar dock miljöproblem då de produceras med hjälp av fossila råvaror, vilket leder till utsläpp av växthusgaser. Det är därmed av intresse att minska effekten som kompositer har på miljö och hälsa genom att istället använda grönare förstärkningsmedel som exempelvis cellulosa.  I denna studie användes cellulosaoxalat (COX) som förstärkningsmedel, maleinsyraanhydridpolypropylen (MAPP) som kopplingsmedel och polypropylen (PP) som matris. COX:et pH-justerades till pH 8 för att öka dess termiska stabilitet med 30°C, sedan torkades det i ugn och mortlades därefter till ett fint pulver. Hydroxylgrupper i oxalatet ökar bindningsstyrkan mellan den hydrofila änden av MAPP:en och COX:et, medan den hydrofoba änden av MAPP:en binder till PP via van der Waals krafter. Två koncentrationer av MAPP, 1 vt% och 2 vt% per 10 vt% COX av slutkompositen testades. Genom att använda COX och MAPP istället för obehandlad cellulosa kan interaktionen vid gränsskiktet förbättras och ett starkare material erhållas. Extrudering och injektionsformsprutning användes för att producera och forma kompositen samt referensprover. De två former som producerades var enligt ISO 527-2-1 och ISO 178 för drag- respektive böjtester. Testerna används för att bestämma provernas mekaniska egenskaper. Smältflödesindex utfördes också enligt standarden ISO 1133 för att få en indikation om ändringar i viskositeten. Resultatet visade att ett förhållande på 1:10 vt% MAPP till COX gav upphov till större E - modul, dragspänning och böjspänning, men lägre brottgräns, än om förhållandet var 1:5. Användningen av MAPP minskar E-modulen i kompositen, men gav upphov till högre maximal drag- och böjspänning samt högre brottpunkt jämfört med prover utan MAPP. Detta är en tydlig indikation att interaktionen vid gränsskiktet har förbättrats och att användning av kopplingsmedel vid produktion av kompositer är väsentlig. Högre koncentrationer av COX gav dessutom upphov till att E-modulen och den maximala kraften provet kunde motstå ökade. Data för glasfiber som förstärkningsmaterial i PP erhölls från äldre litteratur och jämfördes med resultaten för COX. Vid jämförelsen visades att alla mekaniska egenskaper, bortsett från töjningen vid brottgränsen, var lägre för kompositer med COX än för glasfiber. COX kan alltså inte användas som en direkt ersättning till glasfiber i alla situationer, utan en del av användningsområdena blir begränsade. Resultatet av smältflödesindex påvisade att smältflödet av kompositen nästan halverades för varje 10 vt% av tillsatt COX, en tydlig indikation på att viskositeten ökat.

Rapporten presenterar en studie där tre trätyper, balsa, ask och björk, fabriceras genom en förutbestämd metod till transparent trä. Detta material har många möjliga applikationer, inklusive energieffektiva byggnader, förpackningar, solceller och elektroniska apparater. Syftet med studien är att jämföra de erhållna proverna av transparent trä utifrån morfologi och optiska egenskaper samt koppla dessa resultat till mikrostruktur. Detta för att avgöra huruvida den specifika fabriceringsmetoden lämpar sig för trätyperna och vilken som är mest lämpad. Den valda fabriceringsmetoden består av tre steg, delignifiering, tvätt med lösningsmedel samt polymerinfiltration. Syftet med det första steget i processen, delignifieringen, är att ta bort lignin, beståndsdelen i trä som ger träet dess färg. Detta skedde genom kemikaliebehandling med acetatbuffer och natriumklorit i sur miljö under uppvärmning, varvid träproverna blev vita. Proverna placerades därefter i en vakuumdesickator där de tvättades med etanol och därefter aceton. Etanol hindrar fibrerna från att krympa och acetonet tar bort de sista kemikalieresterna i trästrukturen. Inför det sista steget, polymerinfiltrationen, polymeriserades monomerer av metylmetakrylat till oligomerer, varpå dessa pressades in i träproverna med vakuum där de polymeriserades till polymetylmetakrylat (PMMA). PMMA har ett liknande brytningsindex till trä, vilket minskar ljusspridningen och ökar transparensen i provet. Vidare placerades träproverna mellan två glasplattor och lindades in i aluminiumfolie. Proverna värmdes i ugn där polymeriseringen slutfördes och det transparenta träet erhölls. Träprovernas optiska egenskaper och morfologi karakteriserades. För att bestämma optiska egenskaper uppmättes transmittans och haze. Transmittansen anger hur mycket ljus som kan passera genom provet, medan haze anger hur mycket ljusspridning som sker i förhållande till transmittansen. Dessa parametrar uppmättes enligt ASTM D1003 “Standard Method for Haze and Luminous Transmittance of Transparent Plastics”. Provernas morfologi karakteriserades med ett svepelektronmikroskop (SEM) och resultaten presenterades med högupplösta bilder. Från dessaanalyserades mikrostrukturen i träproverna och graden av delignifiering och polymerinfiltration bedömdes. Resultaten från mätningarna av de optiska egenskaperna visade att balsa har den högsta transmittansen (81–87%), följt av björk (74–83%) och sedan ask (66–78% för sommarved och 74–83% för vårved). Vidare uppmättes haze till ca 65–70% för balsa, ca 70–75% för björk och 74-80% för ask. Genom analys av SEM-bilderna bedömdes graden av delignifiering som högst i balsaträet. För att avgöra detta studerades mellanrummet mellan fibrerna som i obehandlat trä är ligninfyllda. Det observerades då att dessa mellanrum var mest tomma i det delignifierade balsaträt, vilket antydde på att graden av delignifiering var högst för denna trätyp. Graden av polymerinfiltrering ansågs likvärdig för de tre träsorterna då det förekom luftfickor i samtliga träprov. Sammanlagt ledde detta till att balsa blev mest transparent av de tre träsorterna, och är den mest lämpade träsorten för denna fabriceringsmetod.

Plastic waste is a severe environmental problem in today's society which has been noticed and discussed during the last couple of years. A constant increase of production over the last decades hasled to a large amount of plastic waste ending up in oceans as microplastics. With harder restrictions of plastic use from the European Parliament, alternative plastics that are bio-based and therefore degradable have increased in demand. The aim of this project was therefore to synthesize alignocellulose-based material which contains the minimum amount of latex, the plastic component, while still satisfying the same requirements as a thermoplastic. The original idea was to create the latex with PISA-RAFT technique however, this was not possible since the needed materials could not be delivered due to COVID-19, therefore radical emulsion polymerization was carried out. Two latexes were synthesized to create composites with wheat-straw, latex A and latex B. Both latexes consisted of 75% of monomer vinyl acetate (VAc) which was the main component but with different weight percentages of monomers methacrylic acid (MAA) and methyl methacrylate (MMA). Latex A consisted of 20 % MAA and 5% MMA and latex B consisted of 20% MMA and 5% MAA. Latex A and latex B were then mixed with wheat straw to create composites. Due to problems withthe wheat-straw composites one additional composite was created to be able to do all of the analyses. This composite was created by using filter paper as biofiber to mix with the two different latexes. Various characterization analyses including FE-SEM, DLS, DSC, FTIR, NMR, TGA and tensile tests were performed on the composites. The NMR and DSC analyses indicated that the actual composition of monomers differs from the theoretical composition and demonstrates that the presence of MAA is hard to detect. This is due to the DSC value for latex A experimental Tg being lower than latex B experimental Tg when latex A consists of more MAA which has a higher detected Tg. During the NMR analysis MAA was also not detected in either latex A nor latex B. The analyses of FTIR contradicts the NMR and DSC analyses hence peaks believed to be from MAA are detected. When comparing the analysis for latex A and B, DLS analysis resulted in latex A having a low PDI and a bigger emulsion sphere size which is preferred when producing composites. The tensile test resulted in latex B achieving the higher values for Young’s modulus and max stress while latex A had a higher value for strain at break. The TGA and DSC analysis however resulted in latex B having a higher Tg and higher thermal stability. The overall analyses indicated that latex B was the most optimal choice for composite production with aslight difference. The analysis of the composites indicated by FE-SEM that the interaction between latex and filter paper were higher than for latex and wheat straw. A total of four wheat-straw composites were created with the weight-ratio of wheat-straw:latex, 50:50 and 75:50 for both latex A and B. Due to not being able to grind the wheat straw to the minimum size needed to create composites only FE-SEM and FTIR analyses of the wheat-straw composites could be made. Because of this no conclusion could be made whether the 75:50 or 50:50 weight ratio was the most optimal. / Plastavfall är ett allvarligt miljöproblem i dagens samhälle som uppmärksammats mycket under de senaste åren. En ständig ökning i produktionen under de senaste decennier har lett till att stora mängder plast hamnat i haven där de sönderdelas till mikroplaster. Med strängare krav av plastanvändning från Europaparlamentet har nya alternativa plaster som är biobaserade och därmed nedbrytbara ökat i efterfråga. Målet med detta projekt var därför att syntetisera ett lignocellulosabaserat material som innehåller så lite icke-nedbrytbar latex, plastkomponenten, som möjligt utan att behöva mista de egenskaper som efterfrågas av termoplaster idag. Den ursprungliga idén var att syntetisera latexen genom PISA-RAFT tekniken, dessvärre pga rådande omständigheter gällande COVID-19 var detta inte möjligt då materialen som behövdes inte kunde levereras. Därför syntetiserades latexen genom emulsionspolymerisation istället. På grund av problem med halmen skapades två olika typer av kompositer, halm kompositer och filterpapper kompositer. De två kompositerna gjordes i två varianter, en innehållande latex A och en med latex B. Latex A och B syntetiserades av olika mängd monomerer vilka var metakrylsyra (MAA) och metylmetakrylat (MMA). Både latex A och B innehöll 75 % av monomeren vinylacetat (VAc). Olika karakteriseringsmetoder, FE-SEM, DLS, DSC, FTIR, NMR, TGA och tensile test utfördes på kompositerna. NMR och DSC analyserna indikerade att den analyserade kompositionen av monomererna skiljer sig åt från den teoretiska kompositionen då närvaron av MAA var svår att detektera. FTIR analysen motsäger dock de analyserade värdena av NMR och DSC då MAA tros ha detekteras då. För jämförelsen av latex A och B resulterade DLS i lägre PDI och större emulsions sfärer för latex A vilket föredras vid produktion av kompositer. Genom analys av tensile test uppnådde latex B högre värden för Young`s modul och max stress medans latex A uppnådde högre värden för belastning vid brottet. TGA och DSC analysen resulterade dock i högre Tg och högre termisk stabilitet för latex B. Den övergripande analysen indikerade att latex B var det mer optimala valet för kompositproduktion meden liten skillnad i jämförelse. Analysen av kompositerna genom FE-SEM indikerade att interaktionen mellan latex och filterpapper var högre än latex och halmen. Total skapades fyra halm kompositer med halm:latex viktförhållandet 50:50 och 75:50 för både latex A och B. Till följd av att halmen inte kunde malas ned till den minimala storleken som behövdes för att bilda kompositer, kunde endast FE-SEM och FTIR analyser utföras. På grund av detta kunde ingen slutsats dras om vilket viktförhållande, 50:50 eller 75:50, som bildade den mest optimala kompositen.

Superhydrophobic fabrics have gained a huge interest in the industries recently. New legislation pushes the industries to eliminate the use of fluorinated materials in the production of these type of fabrics. Hydrophobic and self-cleaning garments textiles can deliver stable water repellent properties without the need for fluorinated chemicals and reduce the consumption of detergents. New methods that could be implemented in current textile industry processes without major changes in instruments or materials is essential to move this industry to the next level. Filament development with the hydrophobic structure without coating could be strategic on one side and tricky on the other side. It has been proved that a stable hydrophobic self cleaning surface needs a hierarchical micro-nano structure to present sustainable properties. In this thesis, we used common materials in the textile industry for filament production which are polyethylene terephthalate (PET) and high molecular weight polystyrene (PS) and low molecular weight polystyrene (LMPS) to shape the microstructures on the surface of filaments. By adding the common compatibilizer polystyrene-co-maleic anhydride (PSMA) to the blend, PS in the matrix of PET could migrate to the surface. Even 1% wt. of PSMA boosted the migration of PS polymer droplets to the surface. The blend including compatibilizer was compounded, melt-spun into the monofilament, drawn, and annealed for various time durations in the furnace. Next, the filaments were immersed in tetrahydrofuran(THF) to remove the PS component obtaining the rough surface. We investigated the effect of mixture components content and different process parameters such as draw ratio and annealing time on hydrophobicity by the aid of statistical design. Applying the Wilhelmy method for contact angle measurement, we could achieve an advancing contact angle (ACA)of 114º and the average ACA of 96º by making micro-size structure on raw PET with an average ACA of 80º and the intrinsic contact angle of around 70º.

Organic solar cells have shown great promise of becoming a cheaper alternative to inorganic solar cells. Additionally, they can also be made semitransparent. To avoid using expensive indium tin oxide electrodes in organic solar cells the electrodes can be made from conductive polymer, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). However, these so-called PEDOT-PEDOT solar cells are prone to short-circuiting. The work behind this thesis thus aimed to find the cause of these short circuits. The initial working hypothesis assumed the hygroscopic PSS in the bottom electrode could attract water across the active layer when the top electrode layer was applied. This would then swell the bottom electrode and cause the active layer to crack leading to short circuits. Accordingly, swelling was investigated as it was suspected to be the main cause of the shorts. This was achieved by coating reflective substrates with different layers from the solar cell, dropping water on top of the stack and then filming the thin film interference effects. SEM, AFM and IR were also used for further analysis. Although the bottom electrode swells, it was found that water does not cause permanent cracking. Instead, the research unveiled that water causes a formation of blisters, which are suspected to be made of PSS. The exact mechanism for the formation of the shorts remains unclear however.

The present work describes the preparation of hyaluronan derivatives and hydrogels with potential use in tissue engineering applications. A potentially injectable hydrogel consisting of hyaluronan and collagen was successfully used to grow neurons in vitro by encapsulation of neural stem and progenitor cells. Attempts were further made to establish a suitable modification strategy which could be used for the preparation of in vivo cross-linkable hyaluronan derivatives. The synthesis of a model substance consisting of a D-glucuronate derivative which could simplify the development of such a modification technique is described, although a new method to prepare hyaluronan derivatives was found without its use. The modification strategy involves the use of a triazine-reagent which enables the covalent attachment of hydrophilic and hydrophobic amines to hyaluronan carboxyl groups in a controlled fashion under mild conditions. Using triazine-activated amidation we synthesized an aldehyde-derivative of hyaluronan which was used to prepare gels by cross-linking with hydrazide-modified polyvinyl-alcohol. Gels were formed in less than 1 minute by mixing equal volumes of the polymer derivatives and they were subsequently used as a carrier for bone morphogenetic protein-2. An in vitro release study showed that approximately 88% of the growth factor is retained in the gel over a 4 week period. The ability to form new bone in vivo was further evaluated in an ectopic rat model by the injection of gels containing 30 µg BMP-2. Radiographic and histological examination 4 and 10 weeks after injection showed the formation of new bone without any signs of inflammation or foreign body response. Hydroxyapatite particles were further added to improve the mechanical properties of the gel, and a comparative study was conducted. This time the induced tissue consisted not only of bone, but also of interconnected cartilage and tendon, as confirmed by histology and immunohistochemistry.

Linear and branched poly(butylene adipate) polyesters with number-average molecular weights ranging from 700 to 10 000 g/mol, and degrees of branching ranging from very low to hyperbranched were solution cast with PVC to study the effects of chemical structure, molecular weight, end-group functionality, and chain architecture on plasticizing efficiency and durability. Miscibility was evaluated by the existence of a single glass transition temperature and a shift of the carbonyl group absorption band. Desirable mechanical properties were achieved in flexible PVC films containing 40 weight-% of polyester plasticizer. Methyl-ester-terminated polyesters with a low degree of branching and an intermediate molecular weight enhanced the plasticizing efficiency, as shown by greater elongation, good miscibility, and reduced surface segregation. A solid-phase extraction method was developed to extract the low molecular weight products that migrated from pure poly(butylene adipate) and PVC/ poly(butylene adipate) films during aging in water. The effects of branching, molecular weight, end-group functionality, and polydispersity on plasticizer permanence were evaluated by quantification of low molecular weight hydrolysis products, weight loss, surface segregation, and the preservation of material properties during aging. A more migration-resistant polymeric plasticizer was obtained by combining a low degree of branching, hydrolysis-protecting end-groups, and higher molecular weight of the polyester. Films plasticized with a slightly branched polyester showed the best durability and preservation of material and mechanical properties during aging. A high degree of branching resulted in partial miscibility with PVC, poor mechanical properties, and low migration resistance. The thermal stability of polyester-plasticized films was higher than that of films containing a low molecular weight plasticizer, and the stabilizing effect increased with increasing plasticizer concentration. / QC 20100805