Organic electrode materials represent an intriguing alternative to their inorganic counterparts due to their sustainable and environmental-friendly properties. Their plastic character allows for the realization of light-weight, versatile and disposable devices for energy storage. Conducting redox polymers (CRPs) are one type of the organic electrode materials involved, which consist of a π-conjugated polymer backbone and covalently attached redox units, the so-called pendant. The polymer backbone can provide conductivity while it is oxidized or reduced (i. e., p- or n-doped) and the concurrent redox chemistry of the pendant provides charge capacity. The combination of these two components enables CRPs to provide both high charge capacity and high power capability. This dyad polymeric framework provides a solution to the two main problems associated with organic electrode materials based on small molecules: the dissolution of the active material in the electrolyte, and the sluggish charge transport within the material. This thesis introduces a general synthetic strategy to obtain the monomeric CRPs building blocks, followed by electrochemical polymerization to afford the active CRPs material. The choice of pendant and of polymer backbone depends on the potential match between these two components, i.e. the redox reaction of the pendant and the doping of backbone occurring within the same potential region. In the thesis, terephthalate and polythiophene were selected as the pendant and polymer backbone respectively, to get access to low potential CRPs. It was found that the presence of a non-conjugated linker between polymer backbone and pendant is essential for the polymerizability of the monomers as well as for the preservation of individual redox activities. The resulting CRPs exhibited fast charge transport within the polymer film and low activation barriers for charge propagation. These low potential CRPs were designed as the anode materials for energy storage applications. The combination of redox active pendant as charge carrier and a conductive polymer backbone reveals new insights into the requirements of organic matter based electrical energy storage materials.

Plant derived oils bear intrinsic double-bond functionality that can be utilized directly for the thiol–ene reaction. Although terminal unsaturations are far more reactive than internal ones, studies on the reversible addition of thiyl radicals to 1,2-disubstituted alkenes show that this is an important reaction. To investigate the thiol–ene coupling reaction involving these enes, stoichiometric mixtures of a trifunctional propionate thiol with monounsaturated fatty acid methyl esters (methyl oleate or methyl elaidate) supplemented with 2.0 wt.% Irgacure 184 were subjected to 365-nm UV-irradiation and the chemical changes monitored. Continuous (RT– FTIR) and discontinuous (NMR and FT–Raman) techniques were used to follow the progress of the reaction and reveal details of the products formed. Experimental results supported by numerical kinetic simulations of the system confirm the reaction mechanism showing a very fast cis/trans-isomerization of the alkene monomers (<1.0 min) when compared to the total disappearance of double-bonds, indicating that the rate-limiting step controlling the overall reaction is the hydrogen transfer from the thiol involved in the formation of final product. The loss of total unsaturations equals thiol consumption throughout the entire reaction; although product formation is strongly favoured directly from the trans-ene. This indicates that initial cis/trans-isomer structures affect the kinetics. High thiol–ene conversions could be easily obtained at reasonable rates without major influence of side-reactions demonstrating the suitability of this reaction for network forming purposes from 1,2-disubstituted alkenes. To further illustrate the validity of this concept in the formation of cross-linked thiol–ene films a series of globalide/caprolactone based copolyesters differing in degree of unsaturations along the backbone were photopolymerized in the melt with the same trithiol giving amorphous elastomeric materials with different thermal and viscoelastic properties. High thiol–ene conversions (>80%) were easily attained for all cases at reasonable reaction rates, while maintaining the cure behaviour and independent of functionality. Parallel chain-growth ene homopolymerization was considered negligible when compared with the main coupling route. However, the comonomer feed ratio had impact on the thermoset properties with high ene-density copolymers giving networks with higher glass transition temperature values (Tg) and a narrower distribution of cross-links than films with lower ene composition. The thiol–ene systems evaluated in this study serve as model example for the sustainable use of naturally-occurring 1,2-disubstituted alkenes at making semi-synthetic polymeric materials in high conversions with a range of properties in an environment-friendly way. / Vegetabiliska oljor som innehåller dubbelbindningar kan användas direkt för thiolene reaktioner. Trots att terminala dubbelbindningar är mycket mer reaktiva än interna visar dessa studier att den reversibla additionen av thiyl radikaler till 1,2-disubstituerade alkener är en viktig reaktion. För att undersöka tiol–ene reaktionerna, som ivolverar dessa alkener förbereddes stökiometriska blandningar av en trifunktionell propionat tiol och enkelomättade fettsyrametylestrar (metyloleat eller metyl elaidat) samt 2.0 vikt.% Irgacure 184. Dessa blandningar utsattes för 365-nm UV strålning och de kemiska förändringarna studerades. De kemiska förändringarna analyserades med olika kemiska analysmetoder; realtid RT–FTIR, NMR och FT–Raman. Dessa användes för att analysera de kemiska reaktionerna i realtid och följa bildandet av produkterna. Reaktionsmekanismen bekräftades med hjälp av experimentella data och beräkningar av numeriska och kinetiska simuleringar för systemet. Resultaten visar en mycket snabb cis/trans-isomerisering av alkenmonomeren (<1.0 min) jämfört med den totala förbrukningen av dubbelbindningarna, vilket indikerar att det hastighetsbegränsande steget kontrolleras av väteförflyttningen från tiolen till slutprodukten. Förbrukningen av den totala omättade kolkedjan är lika med tiolförbrukningen under hela reaktionen, även om bildandet av produkten gynnas från trans-enen. Detta indikerar att den första cis/trans-isomerstrukturen påverkar kinetiken. Höga tiol-ene utbyten kan enkelt erhållas relativt snabbt utan inverkan av sidoreaktioner. Detta innebär att denna reaktion kan användas som nätverksbildande reaktion för flerfunktionella 1,2-disubstituted alkenmonomerer. Vidare användes fotopolymerisation i smälta på en serie globalid/kaprolaktonbaserade sampolyestrar med varierad grad av omättnad med samma tritiol vilket resulterade i bildandet av amorfa elastomeriska material med olika termiska och viskoelastiska egenskaper. Hög omsättning (>80%) uppnåddes relativt enkelt för samtliga blandningar oberoende av den initiala funktionaliteten. Homopolymerisation av alkenen var försumbar i jämförelse med den tiol–en-reaktionen. Mängden alkengrupper har inverkan på härdplastsegenskaperna där en hög andel alken ger en nätstruktur med högre glastransitionstemperatur (Tg). Tiol–ene reaktionen utvärderades i modellsystem baserade på naturlig förekommande 1,2-disubstituterade alkener för att demonstrera konceptet med tiol-förnätade halvsyntetiska material. / QC 20110915

The subject of the present licentiate thesis is density functional theorybased electronic structure calculations of organic thermoelectric materials and novel organic molecules. We used the Car-Parrinello molecular dynamics method in order to investigate the electronic structure of “green energy” and “greenchemistry” compounds. First, we have investigated the electronic structure of the poly(3,4-ethylene-dioxythiophene) (PEDOT) and its derivatives - the best studied and successfully implemented by industry organic thermoelectric material. Its transparency, low toxicity and high stability in the oxidized state are combined withan ability to produce electrical current when applying a temperature gradient. This makes PEDOT a perfect “organic metal” and a first candidate for organic thermoelectrogenerators - devices that can produce “green energy” from a temperature difference. The average structures found in these quantum dynamical simulations agree well with earlier static electronic structure studies. The energy gap of two, four and six unit oligomers of PEDOT was calculated and was found to lie in the range of previous theoretical studies. We have also calculatedthe point-charge distributions along the polymer backbone in order to investigate the polaron formed by doping agents of PEDOT. Our analysis allowed us to predict possible localization of the charge in the center of the polymer chain. However, further calculations of the twelve unit PEDOT and its selenium and tellurium derivatives will provide more information. First-principles calculations for the tellurium derivative of PEDOT are here presented for the first time. The second part of our investigation concerns theoretical calculations of novel piperidine-containing acetylene glycols. These molecules were newly synthesized by our experimental collaborators and are expected to provideplant growth stimulation properties, the same as its diacetylene analogs. We performed quantum mechanical calculations of four compounds, presented ananalysis of the highest occupied and lowest unoccupied molecular orbitals and collected detailed information on point-charges for further parametrization of novel molecules for future computational studies. According to these results, the low production yield found in the experiments cannot be attributed to chemical instability in these novel compounds. / <p>QC 20150629</p> / ScalTEG SSF

Thermoset polymers are widely used polymers in the world, but Increase in global plastic pollution and lack of fossil fuel stimulates intense research towards environmentally sustainable materials. Bio-based unsaturated polyesters (UPs) would be an excellent solution to replace oil-based synthetic polyesters. Most of the unsaturated polyesters have been synthesised by ring opening polymerisation (ROP) of cyclic esters or lactides.  In this study, different resins were developed using different initiators such as isosorbide (IS),1,4 butanediol (BD), and cis-2 butene 1,4 diol (C2BD) with monomers like lactide (L) and alpha angelica lactone (AAL) through the ring opening polymerisation process. The produced resins were further characterised by using Fourier Transform Infrared Spectroscopy (FTIR),Nuclear Magnetic Resonance (NMR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimeter (DSC), and Dynamic Mechanical Analysis (DMA).  Synthesis of resin with lactone monomer was not successful while with lactide monomer it was successful. IS-based resin showed better thermal properties compared to other obtained resins. Tg value of IS containing resin was 63°C, thermal stability up to 235°C and Storage modulus about 3841 MPa. These values are comparable with other bio-based resins produced using the same monomer.

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.

Lignin, en av huvudkomponenterna i lignocellulosabiomassa, utgör en stor mängd av sidoströmen från massaindustrin. Lignin är aromatiska makromolekyler som förekommer i rikliga mängder i naturen och uppvisar unika antioxidant-, uv-skyddande, anti-ultravioletta, antikorrosiva och antimikrobiella egenskaper, etc. Ligninbaserade produkter är ännu inte kommersialiserade eftersom de är begränsade av den kemiska heterogeniteten hos lignin som separerats från olika råvaror och producerats i olika industriella processer. Istället förbränns lignin vanligtvis för värme- och elproduktion efter extraktion. Tillvägagångssätt för att bevara värdefulla egenskaper hos lignin och samtidigt övervinna begränsningar har blivit heta ämnen. I detta projekt genomfördes kemiska modifieringar av kraftlignin från olika naturliga råvaror, gran och eukalyptus, där fenolgrupperna ersattes av alkylgrupper med olika kedjelängder (kolnummer 1, 6 och 12). De kemiska strukturerna och de termiska egenskaperna hos kraftlignin studerades med en kombination av analytiska metoder. Egenskaperna hos två typer av tekniska kraftligniner och dess derivat undersöktes även för jämförelse. Resultaten visade att kemiskt modifierat lignin kan vara ett lovande råmaterial för förädlade produkter som till exempel ligninbaserade nanopartiklar. / Lignin, one of the major components in lignocellulose biomass, makes up a large amount of sidestream from the pulp industry. As an abundant feedstock of bio- originated aromatic macromolecules, lignin shows unique antioxidant, UV-protective, anticorrosive, and antimicrobial properties, etc. However, limited by the chemical heterogeneity of lignin separated from different bioresources and industrial procedures as well as its recalcitrance as macromolecules, lignin-based products are not yet commercialized, while lignin is commonly burnt for heat or power generation after extraction. Approaches of preserving valuable properties of lignin meanwhile overcoming limitations have become heated topics. In this project, chemical modifications of kraft lignin from different natural bio-origins, spruce and eucalyptus, were conducted, with alkyl groups of various chain lengths (carbon numbers 1, 6 and 12) substituting the phenolic groups. A combination of analytical methods for characterizing the chemical structures and thermal properties of kraft lignin and chemically modified kraft lignin were studied. Meanwhile, the characteristics of two kinds of technical kraft lignin and their derivatives were investigated for comparison. Results highlighted that chemically modified lignin could be a promising material to serve as a feedstock for value-added products such as lignin-based nanoparticles.

The use of degradable biomedical materials has during the past decades indeed modernized medical science, finding applications in e.g. tissue engineering and drug delivery. The key question is to adapt the material with respect to mechanical properties, surface characteristics and degradation profile to suit the specific application. Degradation products are generally considered non-toxic and they are excreted from the human body. However, large amounts of hydroxy acids may induce a pH decrease and a subsequent inflammatory response at the implantation site. In this study, macromolecular design and a combination of cross-linking and adjusted hydrophilicity are utilized as tools to control and tailor degradation rate and subsequent release of degradation products from biomedical polyester-ethers. A series of different homo- and copolymers of -caprolactone (CL) and 1,5-dioxepan-2-one (DXO) were synthesized and their hydrolytic degradation was monitored in phosphate buffer solution at pH 7.4 and 37 °C for up to 546 days. The various materials comprised linear DXO/CL triblock and multiblock copolymers, PCL linear homopolymer and porous structure, and random cross-linked homo- and copolymers of CL/DXO using 2,2’-bis-(ε-caprolactone-4-yl) propane (BCP) as a cross-linking agent. The results showed that macromolecular engineering and controlled hydrophilicity of cross-linked networks were useful implements for customizing the release rate of acidic degradation products in order to prevent the formation of local acidic environments and thereby reduce the risk of inflammatory responses in the body. / QC 20101109

The use of synthetic materials for tissue and organ reconstruction, i. e. tissue engineering, has become a promising alternative to current surgical therapies and may overcome the shortcomings of the methods in use today. The challenge is in the design and reproducible fabrication of biocompatible and bioresorbable polymers, with suitable surface chemistry, desirable mechanical properties, and the wanted degradation profile. These material properties can be achieved in various manners, including the synthesis of homo- and copolymers along with linear and star-shaped architectures. In many applications the materials’ three-dimensional structure is almost as important as its composition and porous scaffolds with high porosity and interconnected pores that facilitate the in-growth of cells and transportation of nutrients and metabolic waste is desired. In this work linear and star-shaped polymers have been synthesized by ring-opening polymerization using a stannous-based catalyst and a spirocyclic tin initiator. A series of linear copolymers with various combinations of 1,5-dioxepane-2-one (DXO), Llactide (LLA) and ε-caprolactone (CL) have been polymerized using stannous octoate as catalyst. It is shown that the composition of the polymers can be chosen in such a manner that the materials’ mechanical and thermal properties can be predetermined. A solvent-casting and particulate leaching scaffold preparation technique has been developed and used to create three-dimensional structures with interconnected pores. The achieved physical properties of these materials’ should facilitate their use in both soft and hard tissue regeneration. Well defined star-shaped polyesters have been synthesized using a spirocyclic tin initiator where L-lactide was chosen as a model system for the investigation of the polymerization kinetics. Neither the temperature nor the solvent affects the molecular weight or the molecular weight distribution of the star-shaped polymers, which all show a molecular weight distribution below 1.19 and a molecular weight determined by the initial monomer-to-initiator concentration. / QC 20101217

Cross-linked films of ε-caprolactone (CL) and 1,5-dioxepan-2-one (DXO) having various mole fractions of monomers and different cross-link densities were prepared using 2,2’-bis-(-caprolactone-4-yl) propane (BCP) as cross-linking agent and Sn(Oct)2 as catalyst. Reaction parameters were examined to optimize the film-forming conditions. Networks obtained were elastomeric materials, easy to cast and remove from the mould. Effect of CL content and cross-link density on the final properties of the polymer network was evaluated. Thermal, mechanical and surface properties of the films were controlled by monomer feed composition and cross-link density. The films have potential to be used for tissue engineering applications as shown by preliminary cell growth studies. To avoid organometallic catalysts in the synthesis of poly(1,5-dioxepan-2-one) (PDXO), the enzyme-catalyzed ring-opening polymerization (ROP) of DXO was performed with lipase-CA (derived from Candida antarctica) as a biocatalyst. A linear relationship between number-average molecular weight (Mn) and monomer conversion was observed, which suggested that the product molecular weight can be controlled by the stoichiometry of the reactants. The monomer consumption followed a first-order rate law with respect to monomer and no chain termination occurred. Effect of reaction water content, enzyme concentration and polymerization temperature on monomer conversion and polymer properties was studied. An initial activation by heating the enzyme was sufficient to start the polymerization as monomer conversion occurred at room temperature afterwards. Terminal-functionalized polyesters and tri-block polyesters were synthesized by lipase-CA catalyzed ROP of DXO and CL in the presence of an appropriate alcohol as initiator. Alcohol bearing unsaturation introduced a double bond at the chain end of the polyester, which is a useful pathway to synthesize comb polymers. Dihydroxyl compounds were used as macro-initiators to form tri-block polyesters. The enzyme-catalyzed polymerization of lactones has been shown to be a useful method to synthesize metal-free polyesters. / QC 20101221

Polyhydroxyalkanoates (PHAs) are a group of bioplastics, which are produced through microorganisms. They are accumulated in granules inside bacteria’s cell cytoplasm and serve as an energy reserve. Moreover, PHAs are completely biodegradable and biocompatible biopolyesters, which make them to suitable materials for medical applications and replace conventional petrochemical plastics. However, it is not economically feasible to produce PHAs yet, as it is four to nine times as expensive as to produce fossil fuel-based plastics. In order to reduce the price, it is possible to use waste streams rich in carbon and mixed cultures as microorganisms, which was applied in this thesis work. In this study, PHAs were synthesized from a volatile fatty acid (VFA) mixture rich in hexanoic acid, which was produced by anaerobic digestion of waste streams. To be able to obtain the maximum PHA content, the experimental work was separated into a selection phase and a production phase respectively. During the selection step, enrichment of the mixed culture took place during 50 days altering feast/famine cycles. The production phase was then conducted in a fed-batch cultivation to accumulate as much PHAs as possible, while utilizing the enriched mixed culture.  The selection phase was seen as successful since the quantity of synthesized PHA increased with time. Solely polyhydroxybutyrate (PHB) was formed during this period. The specific consumption rates for the hexanoic acid and acetic acid were almost the same in this phase (0.10 g hexanoic acid/(g volatile suspended soilds (VSS),h) and 0.11 g acetic acid/(g VSS,h)), which suggests that the consumption of these majoritarian fatty acids was simultaneous. However, the determined consumption rate for butyric acid was approximately solely half of the values for hexanoic acid and acetic acid. The highest PHA yield obtained in the enrichment phase was 0.26 g PHB/g VFA.  In the production phase, the highest achieved PHA content was 31.4 % of VSS, which was obtained after five hours. Both PHB and polyhydroxyvalerate (PHV) were formed in this phase, even though the quantity of accumulated PHB dominated with its approximately 97 weight-%. / Polyhydroxialkanoater (PHA:er) är en grupp bioplaster som produceras med hjälp av mikroorganismer. De ackumuleras inuti granulater som finns i bakteriers cellcytoplasma, och används som en energireserv. PHA:er är dessutom fullständigt bionedbrytbara och biokompatibla biopolyestrar, vilket gör dem till lämpliga material att applicera inom medicinska preparat och för att ersätta konventionella petrokemiska plaster. Det är däremot inte ekonomiskt fördelaktigt att producera PHA:er än så länge, då det är fyra till nio gånger dyrare att producera än i jämförelse med att producera plaster från fossila bränslen. Ett tillvägagångssätt för att reducera priset är genom att applicera kolrikt avfall som råmaterial och en blandad kultur av mikroorganismer. Det var detta som tillämpades i detta examensarbete vid PHA produktionen. I denna studie syntetiserades PHA:er från en blandning av flyktiga fettsyror rik på hexansyra, som framställts av avfall genom anaerobisk digestion. Det experimentella arbetet delades in i två faser: en selektionsfas och en produktionsfas. Detta för att kunna erhålla högsta möjliga PHA innehåll. Den blandade kulturen av bakterier berikades under selektionsfasen genom applicering av alternerande svält/frossa cykler i 50 dagar. Produktionsfasen utfördes därefter i en så kallad ”fed-batch odling” för att ackumulera högsta möjliga kvantitet av PHA, med hjälp av den berikade kultur blandningen.  Selektionsfasen ansåg vara lyckad, då mängden ackumulerad PHA ökade med tiden. Endast polyhydroxibutyrat (PHB) producerades under berikelsefasen. De erhållna specifika konsumptionshastigheterna för hexansyra och ättiksyra var i samma storleksordning (0.10 g/(g flyktiga suspenderade ämnen, h) respektive 0.11 g/(g flyktiga suspenderade ämnen, h)), vilket tyder på att förbrukningen av dessa fettsyror skedde samtidigt. Konsumptionshastigheten för butansyra var däremot endast cirka hälften av hastigheterna för hexansyra samt ättiksyra. Det högsta PHA-utbytet beräknades till 0.26 g PHB/g flyktiga fettsyror. Det högsta PHA-innehållet som erhölls i produktionsfasen var 31.4 % av de flyktiga suspenderade ämnena, vilket uppmättes efter fem timmar. Både PHB och polyhydroxivalerat (PHV) bildades under denna fas, även om mängden ackumulerad PHB dominerade med 97 vikt-%. / <p>I och med COVID-19 presenterades examensarbetet via zoom</p> / Carbon Neutral Next Generation Wastewater Treatment Plants