Clays are ubiquitous near the Earth’s surface. Medicinal properties of these nontoxic minerals have been intuitively recognized since ancient times. Up till now, clays have been used in pharmaceutical formulations as active agents and excipients. Currently, there is an urgent need to seek advanced, functional materials with low environmental impact. Answering to that trend, clay-biopolymer nanocomposites were synthesized in this thesis and applied in a drug delivery system. In the first part of the thesis, Portuguese clay from a bentonite deposit in Benavila (Portugal) was collected from six sampling sites and characterized. The highest content of clay fraction, approximately 30%, was found in two of the sampling sites. After purification, the smectite-rich samples were analyzed with respect to clay content, mineralogical and chemical composition, physicochemical and mechanical properties. SEM-EDS revealed that the smectite present in the ore is montmorillonite with varying Fe content. This was also indicated by the means of XRD, XRF and FTIR. The Benavila sample, which was richest in smectite, as well as the sodium Wyoming montmorillonite from the Source Clay Repository (SWy-2) were successfully used to synthesize clay-biopolymer nanocomposites. The chosen biopolymers were the plant-extracted polysaccharides – neutral guar gum and its cationic form. The obtained materials were thoroughly characterized by XRD, TGA and NMR, and the intercalated structure was reported. The prepared nanocomposites were loaded with an anti-inflammatory drug ibuprofen and tested in an in-vitro release system. The drug-loaded materials were characterized with XRD, TGA and NMR. A membrane diffusion method was chosen as a dissolution testing strategy and the drug was quantified by UV-Vis spectroscopy. The materials exhibited improved properties as a noticeable reduction of release rate was achieved.

Orientador: Luiz Francisco Malmonge / Resumo: Os fertilizantes de liberação modificada têm conquistado âmbitos cada vez maiores nas pesquisas e em utilizações agrícolas devido a suas principais características de menores perdas de nutrientes e por seu menor custo, que envolve menos aplicações no campo e menores quantidades de fertilizantes utilizados, comparado aos fertilizantes convencionais. Este trabalho teve como objetivo elaborar fertilizantes com possível comportamento de liberação modificada, através da incorporação do fosfato de potássio monobásico (KH2PO4) no polímero quitosana, contribuindo, dessa forma, com as três fontes de nutrientes primários essenciais requeridos pelas plantas: nitrogênio, fósforo e potássio, por apenas dois recursos. Foram elaboradas duas amostras diferentes para posterior comparação, análise e aplicação. Os métodos utilizados no preparo das amostras foram: gotejamento em solução básica coagulante e casting. Foram feitas soluções de 8% de quitosana (m/v) dissolvidas em soluções de 5% de ácido acético, e subsequentemente foi adicionado o KH2PO4 (em diferentes concentrações para análise e para aplicação agrícola, foi usada a concentração de 60% (m/m) em relação à massa de quitosana). Foram feitas Microscopia eletrônica de varredura (MEV) para análise morfológica das amostras, Energia dispersiva de raios-X (EDX) para constatação dos elementos contidos nas amostras, o estudo da liberação dos nutrientes em solução aquosa (em pHs 5,4 e 6,7) e por fim, as amostras foram aplicadas em mudas de alf... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Modified-release fertilizers have been increasingly used in research and in agricultural uses due to their main characteristics of lower nutrient losses and their lower cost, which involves fewer applications in the field and less quantities of utilized fertilizers, compared to the conventional ones. This work aimed to elaborate fertilizers with possible modified release behavior, through the incorporation of monobasic potassium phosphate (KH2PO4) in the chitosan polymer, thus contributing with the three sources of essential primary nutrients required by plants: nitrogen, phosphorus and potassium, from only two resources. Two different samples were prepared for later comparison, analysis and application. The methods used in preparing the samples were: dripping in a basic coagulant solution and casting. Solutions of 8% chitosan (w/v) were prepared dissolved in solutions of 5% acetic acid, and subsequently KH2PO4 was added (in different concentrations for analysis and for agricultural application, the concentration of 60% (w/w) in relation to the chitosan mass). Scanning electron microscopy (SEM) was performed for the morphological analysis of the samples, energy dispersive X ray (EDX) to verify the elements contained in the samples, the study of the release of nutrients in aqueous solution (at pH 5.4 and 6, 7) and finally, the samples were applied to lettuce seedlings for comparative effect and material efficiency. The results of the EDX spectra showed that in the samples made... (Complete abstract click electronic access below) / Mestre

Världens fokus på hållbarhet ökar och utveckling inom biobaserade material är nödvändig för att nå det globala klimatmål som satts upp. Biologiska material kommer frånförnyelsebara resurser, dvs att det både kommer från naturen och är tänkt att brytas ner av naturen. Inom kategorin naturliga polymerer finns proteiner, polysackarider och lipider där framförallt polysackarider fått fokus för användning både som biobränsle och som regenererade fibrer inom textilindustrin. Vete är ett spannmål som består av alla dessa tremakromolekyler. Vete används framförallt inom matindustrin men har på senare tid odlats för dess höga mängd av stärkelse som utvunnits och använts till bland annat biobränsle. Vid denna utvinning av stärkelsen blir resterande proteiner och lipider en biprodukt. Mängden protein är mellan 20-30% i vetet och stor del av detta är gluten. Denna rapport går igenom vad gluten är, hur gluten kan modifieras, vilken potential gluten har att regenereras till en textil fiber och hur en sådan process kan se ut. Gluten är ett vegetabiliskt växtprotein som består av ämnena gliadin och glutenin. Gluten är stabil i högre temperaturer och vattenolöslig, men det har visat sig att gluten vid kontakt med vatten får försämrade mekaniska egenskaper och att gluten har en glasomvandlingstemperatur på ca 38℃, vilket leder till att materialet är sprött vid rumstemperatur. Proteinerna inom gluten innehåller även olika mängder disulfidbindningar, även kallade tvärbindningar. Dessa tvärbindningar påverkar även glutens mekaniska egenskaper, och dess möjlighet att processas vidare. En rapport från 2009 diskuterar glutens potential som en regenererad fiber och tar även upp vilka modifieringar som krävs för att gluten ska kunna regenereras genom våtspinning. Olika modifieringar har olika betydelse för glutens fortsatta processande och med hjälp av en litteratursökning där artiklar och rapporter från tidigare forskning sammanfattats har denna studie gett ett resultat om en potentiell metod för att genomföra vidare tester inriktade mot att producera gluten till en regenererad fiber. Resultatet ger en metod där flera modifieringar sammanflätas i olika steg, där förhoppningen är att hitta den optimala metoden för att processa gluten till en textil fiber. Vidare presenteras en marknadsanalys där resultatet pekar på att odling av vete är stor och stabil. En jämförelse mellan olika marknader och råvaror visar även på ett teoretiskt pris för gluten, där det hamnar i ett intervall mellansyntetiska fibrer och bomull. / Big focus all around the world is on sustainability, where the progress of using biobased material is necessary to reach the global goals of sustainable development. Biological materials is produced from renewable resources, they are extracted from nature and eventually broken down by nature. Within the category of natural polymers is proteins, polysaccharides and lipids, where polysaccharides have got large attention for their use as biofuel and regenerated textile fibers. Wheat is a grain that contains all of this three macromolecules. Wheat is mainly used in the food industry but have lately been produced for it´s high volume of starch which can be useful as biofuel. When starch are extracted, the by-product of this production is proteins and lipids. Proteins are responsible for 20-30% of the content in wheat and the majority of this protein is gluten. This study introduce gluten, it’s properties, how it can be modified, the potential to regenerate gluten as a textile fiber and how that process might look like. Gluten is a vegetable protein containing the substances gliadin and glutenin. Gluten is stable in high temperature and water-insoluble, but in contact with water, the mechanical properties of gluten is decreased. It has also been showed that the glass transition temperature of gluten is 38℃, witch make gluten brittle in room temperature. The proteins within gluten contains disulfide bonds, also called crosslinking bonding. This crosslinking affects the mechanical properties of gluten and also the ability to be processed. An article from 2009 discuss about the potential of gluten as regenerated textile fiber and what modifications that can be made to regenerate gluten in the process of wet-spinning. Different modifications have different implications for the gluten's continued processing, and with the help of a literature search that summarizes articles and reports from previous research, this study has yielded a potential method for conducting further tests aimed at producing gluten into a regenerated fiber. The result provides a method where several modifications are intertwined in different stages, where the hope is to find the optimal method for processing gluten into a textile fiber. Furthermore, a market analysis is presented where the result indicates that wheat cultivation is large and stable. Comparing different markets gives gluten a theoretical price range between synthetic fibers and cotton.

Microspheres are spherically shaped particles within the size range of 1-1000 μm in diameter. Due to the their small size and round shape, microspheres show many advantages in various applications such as pharmaceuticals, composites and coatings. The microspheres can be customized to fit a specific application and are manufactured in various forms such as solid, hollow and encapsulating. Encapsulating cellulose microspheres have been produced in this project by the emulsionsolvent evaporation technique. The purpose of this study was to further investigate the possibility of producing encapsulating microspheres with a size range of 10-50 μm that will have a high encapsulation. A second purpose of this study was optimizing the emulsifier system for the preparation of these spheres. This has been accomplished by varying several process parameters such as type of emulsifiers and solvents to study the effect on morphology and encapsulation efficiency. The analyses of the spheres were performed with optical microscopy, thermal gravimetric analyzer (TGA) and scanning electron microscopy (SEM). The emulsifier type and concentration affected the encapsulation and size distribution but had no direct effect on the internal and external structure, which was multi-cellular and porous, respectively. The highest encapsulation in relation to average size was obtained with 0.1 v/v- % of the emulsifier mixture Emulsifier 1 (E1)/Emulsifier 2 (E2) (70/30 %). The solvent used to dissolve the polymer had a direct effect on encapsulation, a combination of Solvent 2 (S2) and Solvent 1 (S1) proved best for the three tested cellulose derivatives with low, medium and high number average molecular weight. The solvent also had an effect on the internal structure of the microspheres, becoming more core-shell when using the S1/S2 combination.

Plasten Polyvinylklorid har under lång tid kritiserats ur miljösynpunkt på grund av plastens hälsofarliga beståndsdelar. PVC har medfört enorma miljöskador på ozonskiktet som orsakats av klorfluorkolväten men det som framförallt varit bekymrande på senare tid är mjukningsmedel som har skapat oro över deras möjliga hormonstörande effekter. Detta har medfört en politisk osäkerhet och otrygghet för företag som arbetar med PVC. Företaget HRD Carpets AB önskar utveckla ett alternativt ersättningsmaterial för PVC plastmattor och ser helst fram emot en biobaserad lösning. Syftet med denna studie är att finna ett lämpligt ersättningsmaterial för PVC plastmattor. Målet har varit att genomföra en studie som ger underlag för ett alternativt ersättningsmaterial som går att vidareutveckla i form av fortsatta studier. Kravspecifikationen har varit utgångspunkten i denna studie för att finna ett lämpligt ersättningsmaterial. De mekaniska egenskaperna för PVC plasten som används i fabriken har identifierats och tolkats genom ett dragprovningstest som genomförts. Dessa egenskaper har varit de elementära kraven tillsammans med övriga krav som framgår i kravspecifikationen. I denna studie undersöks alternativa biomaterial samt syntetiska material. Med hjälp utav programvaran Cambridge Engineering Selector har ett urval av material tagits fram och undersökts genom en urvalsprocess. Genom intervjuer, publikationer, journaler och litteraturer har biobaserade alternativ undersökts. Resultatet visade att den syntetiska plasten Polybutylentereftalat (PBT) tillsammans med färgämnen uppfyller de basala krav för det tillämpningsområdet som undersöks. Resultatet visade att biomaterialet Polymjölksyra (PLA) och Polybutensuccinat (PBS) uppfyller samtliga krav och kan lämpa sig som alternativa lösningar. Dessa material har dock en kort livslängd och att öka materialets hållbarhet är en utmaning med dessa biomaterial. / The Polyvinyl chloride (PVC) has been criticized from an environmental point of view due to the plastic's hazardous components for a long time. PVC has caused enormous environmental damage to the ozone layer caused by chlorofluorocarbons. The plasticizers used for PVC are concerning because of their possible endocrine disrupting effects. This has led to political uncertainty and insecurity for companies working with PVC. The company HRD Carpets AB wishes to develop an alternative replacement material for PVC plastic carpets and looks preferably towards a bio-based solution. The purpose of this study is to find a suitable replacement material for PVC plastic carpets. The goal of this study is to provide a basis for an alternative replacement material and can be further developed in the form of further studies. The requirements specifications have been the starting point in this study to find a suitable replacement material. The mechanical properties of PVC, which is used in the company, have been identified and interpreted through a tensile test. These properties have been the elementary requirements combined with other requirements that appear in the requirements specification. This study examines alternative biomaterials and synthetic materials. With the help of the Cambridge Engineering Selector software, a selection of materials was found through a selection process. Then through interviews, publications, journals and literature, bio-based alternatives have been explored. The results showed that the synthetic plastic Polybutylene Terephthalate (PBT) together with color additives meet the basic requirements specification being investigated. The results also showed that the biomaterial Polylactic Acid (PLA) and Polybutene Succinate (PBS) meet the requirements and can function as alternative solutions. However, these materials have a short lifespan, increasing the durability of the material is a challenge with these biomaterials.

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Polysaccharides and polypeptides are two types of biopolymers that are used in biomedical, industrial, and commercial applications. Both families of biopolymers are generally biodegradable, sustainable, and often exhibit low toxicity. Polysaccharides and polypeptides are polymers derived from natural resources and can be modified or synthesized through polymerization of various monomers. Polypeptides, specifically, are typically synthesized by polymerizing monomers such as N-carboxyanhydrides (NCAs) or N-thiocarboxyanhydrides (NTAs) to form homopolymers or random copolymers when using two different NCA/NTA monomers simultaneously. Chapter 1 begins with a background on polysaccharide and polypeptide-based materials with a focus on polysaccharide-block-polypeptide block copolymers. Previous work includes combining these two biopolymers through methods requiring post-polymerization purification. Chapter 1 introduces the field, challenges it faces, and how this work can help pose some solutions to these challenges. In this thesis, we utilized NTAs to synthesize polypeptides (Chapters 2 and 3) and as an H2S donor (Chapter 4). Combining polysaccharides and polypeptides into a block copolymer is useful for drug delivery and blend compatibilization applications. In Chapter 2, we synthesized a dextran-block-poly(benzyl glutamate) block copolymer that is amphiphilic; the differences in hydrophilicity among the two blocks allowed for nanostructures to form in situ in water, which we envision can be used for applications in drug delivery. Because nanostructures are formed in situ, this method negates the need for post-polymerization modification or purification, a requirement of many other nanostructure formation procedures. Coarse-grained molecular dynamics simulations were employed to shed light on interactions found on the molecular level. The interactions studied were then used to explain the nanostructures observed experimentally. In Chapter 3, we similarly formed another polysaccharide-block-polypeptide with the same poly(benzyl glutamate) polypeptide used in Chapter 2 but using ethyl cellulose for the polysaccharide. Poly(benzyl glutamate) is similar in structure to the commercial plastic polyethylene terephthalate (PET), a petroleum-based polymer that is not biodegradable. Therefore, this ethyl cellulose-block-poly(benzyl glutamate) BCP was used as compatibilizer to improve mixing in immiscible ethyl cellulose/PET blends. These blends afforded a more bio-derived alternative to PET/petroleum-based plastics. This chapter focuses on the synthetic efforts, a common challenge with polysaccharides, to produce this block copolymer as well as blend preparation and characterization. Chapter 4 utilizes an NTA as an H2S donor rather than a monomer for polymerization. H2S is an endogenous signaling gas that plays an important role in many organs and systems. In humans, H2S deficiency leads to a range of medical issues including hypertension, preeclampsia, liver diseases, and Alzheimer's disease. NTAs are advantageous for H2S delivery in the biomedical field due to their amino-acid origin and innocuous byproducts. The NTA donor in this work was attached to amylopectin via thiol-ene "click" photochemistry with the amino acid cysteine providing the thiol source on amylopectin. H2S release half-lives were in the range of several hours and depended on polymer molecular weight. Lastly, Chapter 5 summarizes the conclusions formed from these projects as well as potential future extensions from this work. / Doctor of Philosophy / Polysaccharides, long-chain sugars, and polypeptides, long-chain amino acid sequences, are two types of biopolymers that are used in biomedical, industrial, and other commercial applications. Both families of biopolymers are generally biodegradable, sustainable, and often exhibit low toxicity. Chapter 1 begins with a background on polysaccharide and polypeptide-based materials with a focus on polysaccharide-block-polypeptide block copolymers. Chapter 1 introduces the field, challenges it faces, and how this work can help pose some solutions to these challenges. In this thesis, we utilized N-thiocarboxyanhydrides (NTAs) to synthesize polypeptides (Chapters 2 and 3) and as an H2S donor (Chapter 4). In Chapter 2, we synthesized dextran-block-poly(benzyl glutamate), a polysaccharide-block-polypeptide block copolymer, that is both hydrophilic and hydrophobic. The differences in hydrophilicity among the two blocks allowed for nanostructures to form in situ in water, which we envision can be used for applications in drug delivery. Computational modeling was then employed to help explain the nanostructures observed experimentally. In Chapter 3, we similarly formed another type of polysaccharide-block-polypeptide. The polypeptide used is similar in structure to the commercial plastic polyethylene terephthalate (PET), a petroleum-based polyester that is not biodegradable. This block copolymer was then employed to improve mixing between blends of immiscible ethyl cellulose (polysaccharide) and PET. These blends afford a more bio-derived alternative to PET/petroleum-based plastics. This chapter focuses on the synthetic efforts, a common challenge with polysaccharides, to produce this block copolymer as well as blend preparation and characterization. Chapter 4 utilizes an NTA as an H2S donor rather than a monomer for polymerization. H2S is an endogenous signaling gas that plays an important signaling role in many organs and systems. In humans, H2S deficiency leads to a range of medical issues including hypertension, preeclampsia, liver diseases, and Alzheimer's disease. In this work, we synthesized a polymeric polysaccharide H2S donor with tunable release rates, which is beneficial for longer therapeutic time and increased patient compliance. Lastly, Chapter 5 summarizes the conclusions formed from these projects as well as potential future extensions from this work.

The design and discovery of new surface-active polymers that self-assemble on solid substrates to form brush layers will have a major impact on numerous applications. Through recombinant DNA technology, there exists the potential to harness a cell's protein synthesis machinery to produce a brush-forming poly(amino acid) (or PAA) with an exactly specified amino acid sequence, thus controlling the polymer's composition at a level unequaled by conventional organic polymer synthesis. The presented work demonstrates the cloning, expression, purification and characterization of de novo-designed PAA's designed to form brush layers on alumina surfaces. Using conventional recombinant DNA methods, the feasibility of producing a PAA consisting of a poly-glutamate block and a poly-proline block was demonstrated. However, the PAA design was limited by the inherent limitations of conventional cloning techniques. We introduce here the development of a simple and versatile strategy for producing de novo-designed, high molecular weight PAA's using recombinant DNA technology. The basis of this strategy is that small DNA modules encoding for short PAA blocks can be easily inserted directly into a commercially available and unmodified expression vector. The insertions can be made repeatedly until the gene encodes for a polymer of desired molecular weight and composition. Thus, sequential modifications can be made to the PAA without having to re-start the gene assembly process from the beginning, thereby allowing for quick determination of how these changes affect polymer structure and function. The feasibility and simplicity of this method was shown during the production of a PAA, consisting of a long zwitterionic tail block and a short acidic anchor block, designed to form optimal brush layers on alumina surfaces. The success and flexibility of this method indicates that it can be applied for production of de novo-designed polypeptides in general. It is hoped that this method will contribute towards the rapid development of bio-inspired protein-based polymers for a variety of applications. This dissertation also contains research that aimed to use phage display technology to develop a new liposome-based immunoassay against biological toxins. This work was part of a collaboration effort with the U.S. Department of Defense and Luna Innovations. / Ph. D.

Synthetic plastics are intrinsic to modern human existence. Unfortunately, many challenges exist related to the accumulation of plastic waste, including greenhouse gas emissions, contamination of natural environments, and entrance into the food chain through microplastics. Therefore, new polymers are being developed that both compete with the capabilities and costs of petroleum-based plastics and have assured biodegradability. Through decades of research, plant oils have emerged as one of the leading options for alternative starting materials because of their feasibility for use in polymerization reactions, wide availability, renewability, and cost-effectiveness. In this work, cottonseed oil (CSO) and soybean oil (SBO) are successfully utilized to synthesize polymers with a range of promising properties. A nanocomposite was produced by incorporating cellulose nanocrystals (CNCs) into an epoxidized CSO (ECSO) polymer matrix. A significant improvement in properties such as tensile stiffness and strength, without any substantial decrease in extensibility or thermal integrity has been observed. This demonstrated that CNCs can be used to tune the CSO- based polymer properties. Enzymes are excellent alternatives to traditional catalysts as they eliminate the necessity of elevated reaction temperatures and pressures. Epoxidized SBO (ESBO) was polymerized using immobilized candida antarctica lipase B (Novozyme N435). The resulting polymer was inhomogeneous, with soluble waxy and insoluble solid components. Analyses of the soluble component indicated the formation of a multi-branched polymer, showing that a greener system may be used to produce ESBO-based polymers. It is necessary to test the biodegradability of biobased polymers to confirm their validity as alternatives to traditional plastics. Degradation of the CNC-incorporated CSO-based network polymer was characterized by submersing specimens into various aqueous media, including artificial seawater and saltwater, to simulate realistic end-of-use scenarios. Decomposition occurred due to hydrolysis of the many ester linkages within the polymer structure. The presence of CNCs appeared to enhance the rate of degradation. Overall, the hydrolytic susceptibility of the CSO-based network polymer was observed as enhanced by incorporating CNCs. In summary, this work demonstrates the viability of using plant oils and CNCs to produce biodegradable polymers with a range of properties, thus aiding in the effort to replace traditional plastics.