The thesis deals with composting and ways of handling biodegradable waste and biodegradable municipal waste. It explains the terms related to composting and processing of BW and BMW and clarifies the difference between humus and primary organic matter and its composition. Furthermore, the thesis covers qualitative and quantitative features of compost, raw material composition of the dump, and factors influencing the process of decomposition itself. The practical part of the thesis describes the quality of the compost from the municipal composting plant Písek. This part also includes a description of the composting plant and a description of the composting process. The main part and the goal of the thesis is to determine the ion-exchange capacity T according to Sandhoff and to suggest the optimal composting technology in the Municipal composting plant Písek.

Made available in DSpace on 2014-07-29T15:12:47Z (GMT). No. of bitstreams: 1 dissertacao Leonardo Francois quimica.pdf: 194110 bytes, checksum: 750a31eb02f149c7536ac63de960592b (MD5) Previous issue date: 2008-11-27 / In this study PLGA copolymers were synthesized with molecular weight above 10 kDa through direct polycondensation of L-lactic acid and glycolic acid monomers. Catalysts based on sulfonated styrenedivinylbenzene copolymer (SC) containing or not Sn2+ íons adsorbed as SnCl2.H2O colloidal particles from neutral solution or [SnCl3]- complex anions from acid solution were prepared. All catalysts were evaluated by specific surface area and pore volume measurements, infrared spectroscopy, X-ray diffraction, atomic absorption spectrophotometry and ion exchange capacity. The obtained PLGA copolymers were characterized by infrared spectroscopy, X-ray diffraction and inherent viscosity measurements. Independent of pH solution of the adsorptions, it was observed that Sn2+ ions were oxidized to Sn4+ forming SnO2. This oxidation probably occurred during catalysts drying process in the presence of oxygen. The PLGA copolymers with highest inherent viscosities, i.e., highest molecular weights were obtained with SC catalyst containing SnO2 prepared by adsorption of SnCl2.H2O colloidal particles in neutral solution. It was estimated that the highest PLGA molecular weights were equal or larger than 35 kDa. The produced PLGA presented white or lightly yellow color and Sn contamination less than 1 ppm which is below the limit allowed by the Brazilian legislation / No presente trabalho foram sintetizados copolímeros PLGA com massa molar acima de 10 kDa por policondensação direta dos monômeros ácido L-láctico e ácido glicólico. Foram preparados catalisadores à base de copolímero estireno-divinilbenzeno sulfonado (CS) contendo ou não íons Sn2+ adsorvidos na forma de partículas coloidais de SnCl2.H2O em meio neutro ou na forma do ânion complexo [SnCl3]- em meio ácido. Todos os catalisadores foram avaliados por medidas de área superficial específica e volume de poros, espectroscopia de infravermelho, difração de raios X, espectrofotometria de absorção atômica e capacidade de troca iônica. Os copolímeros PLGA obtidos foram caracterizados por espectroscopia de infravermelho, difração de raios X e medidas de viscosidade inerente. Foi verificado que independente do pH do meio de adsorção, os íons Sn2+ foram oxidados a Sn4+ formando o óxido SnO2. Essa oxidação ocorreu, provavelmente, durante o processo de secagem dos catalisadores na presença de oxigênio. Os copolímeros PLGA com maiores viscosidades inerentes, ou seja, maiores massas moleculares foram obtidos pelo uso de catalisador CS contendo SnO2 preparado pela adsorção de partículas coloidais de SnCl2.H2O em meio neutro. Foi estimado que as maiores massas moleculares de PLGA foram iguais ou maiores que 35 kDa. Os copolímeros PLGA produzidos apresentaram coloração branca ou levemente amarelada e contaminação por Sn inferior a 1 ppm bem abaixo do limite permitido pela Legislação Brasileira

Theoretical part of present study gives a comprehensive overview of the methods used for the disposal of biodegradable waste with emphasis placed on highly effective techniques. Composting process is studied in detail and machinery used is thoroughly described. Acquired information from extensive research was applied to create a model of composting plant. Operation manual for this specific model forms part of the study. Afterwards various decomposing scenarios are analyzed and their economic sustainability is evaluated.

Master of Science / Department of Grain Science and Industry / Sajid Alavi / Plastics from petroleum sources are the main raw materials used for producing food packaging films. But these plastic films cause a great environmental concern due to their non-degradable nature and non-renewable source. Biodegradable polymers like starch can be used as a base material which can replace petroleum based plastics packaging. In this study, starch (0-80%) and polyvinyl alcohol (PVOH) (20-100%) were used as base polymers to produce nanocomposites. Glycerol (30%) and sodium montmorillonite (0-20%) were used as a plasticizer and nano-filler, respectively. Nanocomposites were produced through two methods: solution and melt extrusion method. Extrusion method resulted in greater exfoliation of nanocomposites than solution method because it provided more shear stress to disrupt the layered silicate structure. In extrusion method, a lab scale extruder was used to produce these nanocomposites and films were made by casting. Process parameters, including screw speed (200-400 RPM) and barrel temperature (145-165[superscript]oC), were varied systematically. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were conducted to characterize the nanostructure of these nanocomposites. Thermal characterization of these films was carried out through differential scanning calorimetric (DSC) studies. Results from XRD and TEM explained the phenomenon of intercalation and exfoliation in these nanocomposites. Structural and thermal data indicated important role for Na[superscript]+MMT along with process parameters in controlling exfoliation and glass transition temperature of the nanocomposites. These results also helped in understanding the fundamental interactions among all the components. The tensile strength and elongation at break of films ranged from 4.72 to 23.01MPa and 63.40 to 330.15% respectively, while water vapor permeability ranged from 1.68 to 0.79g.mm/kPa.h.m[superscript]2. These results provide a great understanding for further improvements in order to bring these films close to commercial plastic films which have superior tensile strength (10-80MPa), elongation at break (200-800%) and water vapor permeability (0.002- 0.05g.mm/kPa.h.m[superscript]2). The cost for polyethylene is approximately $0.70/lb while the raw material cost for this starch based films is approximately $0.85/lb.

Doctor of Philosophy / Department of Grain Science and Industry / X. Susan Sun / Biobased polymers derived from renewable resources are increasingly important due to acute concerns about the environmental issues and limited petroleum resources. Poly(lactic acid) (PLA) is such a polymer that has shown great potential to produce biodegradable plastics. However, low glass transition temperature (Tg), low thermal stability, slow biodegradation rate, and high cost limit its broad applications. This dissertation seeks to overcome these limitations by reinforcing PLA with inorganic nanoparticles and low-cost agricultural residues. We first synthesized PLA nanocomposites by in situ melt polycondensation of L-lactic acid and surface-hydroxylized nanoparticles (MgO nanocrystals and TiO2 nanowires) and investigated the structure-property relationships. PLA grafted nanoparticles (PLA-g-MgO, PLA-g-TiO2) were isolated from the bulk nanocomposites via repeated dispersion/centrifugation processes. The covalent grafting of PLA chains onto nanoparticle surface was confirmed by Fourier transform infrared spectroscopy and thermalgravimetric analysis (TGA). Transmission electron microscopy and differential scanning calorimetry (DSC) results also sustained the presence of the third phase. Morphological images showed uniform dispersion of nanoparticles in the PLA matrix and demonstrated a strong interfacial interaction between them. Calculation based on TGA revealed that more than 42.5% PLA was successfully grafted into PLA-g-MgO and more than 30% was grafted into PLA-g-TiO2. Those grafted PLA chains exhibited significantly increased thermal stability. The Tg of PLA-g-TiO2 was improved by 7 °C compared with that of pure PLA. We also reinforced PLA with low-value agricultural residues, including wood flour (WF), soy flour (SF), and distillers dried grains with solubles (DDGS) by thermal blending. Tensile measurements and morphological images indicated that methylene diphenyl diisocyanate (MDI) was an effective coupling agent for PLA/WF and PLA/DDGS systems. MDI compatibilized PLA/WF and PLA/DDGS composites showed comparable tensile strength and elongation at break as pure PLA, with obviously increased Young’s modulus. Increased crystallinity was observed for PLA composites with SF and DDGS. Such PLA composites have similar or superior properties compared with pure PLA, especially at a lower cost and higher biodegradation rate than pure PLA. The results from this study are promising. These novel PLA thermoplastic composites with enhanced properties have potential for many applications, such as packaging materials, textiles, appliance components, autoparts, and medical implants.

In our practice the choice of materials is mostly driven by practical reasons, aesthetics and a given budget, and it is often applied rather at the end of the process – rarely is it the driver of any design process. What often gets forgotten is that materials can carry an immaterial layer of connotations. This means that materials are not perceived neutrally but are instead always loaded with certain meanings and values we attribute to them which in return can evoke different emotions in us. In my thesis project I explore the effect of analternative design process that uses materials as the point of departure.Through experimental explorations I have produced my own materials and investigated possibilities to use them in a spatial context. I created different scenarios to speculate about the potential these materials could have. Could they become applicable materials for interior and furniture design as well as for being a carrier of meaning?

Polymeric fibres influence our everyday life in numerous aspects; the area of applications ranges from industrial to everyday commodities, textile and non-textile. As the global demand for the polymeric fibres increases rapidly, new innovative classes of fibres and the manufacturing processes are sought after. This thesis develops an approach to produce fine cell structure and low void fraction foams, which is then used in the manufacturing of lightweight, biodegradable foam fibres. Poly (lactic) acid-clay nanocomposite have been foamed with nitrogen and drawn to different melt draw ratio to produce foam fibres. The foam fibres are then characterized for crystallinity, Young’s modulus and the yield stress. While the drawability of foam has been demonstrated, the crystallinity as well as the mechanical properties of the foam fibres are not drastically enhanced by drawing, as would be expected. Further drawing processes of the as-spun foam fibres are recommended.

Polymeric fibres influence our everyday life in numerous aspects; the area of applications ranges from industrial to everyday commodities, textile and non-textile. As the global demand for the polymeric fibres increases rapidly, new innovative classes of fibres and the manufacturing processes are sought after. This thesis develops an approach to produce fine cell structure and low void fraction foams, which is then used in the manufacturing of lightweight, biodegradable foam fibres. Poly (lactic) acid-clay nanocomposite have been foamed with nitrogen and drawn to different melt draw ratio to produce foam fibres. The foam fibres are then characterized for crystallinity, Young’s modulus and the yield stress. While the drawability of foam has been demonstrated, the crystallinity as well as the mechanical properties of the foam fibres are not drastically enhanced by drawing, as would be expected. Further drawing processes of the as-spun foam fibres are recommended.

<p>Predmet doktorske disertacije je razvoj aktivnog jestivog omotača na bazi hitozana sa dodatkom etarskih ulja začinskog bilja i pčelinjeg voska, kao i njegova aplikacija u cilju produženja održivosti suve fermentisane Petrovačke kobasice.<br />U cilju realizacije programa teze, formirane su tri osnovne grupe filmova: hitozan-etarsko ulje origana, hitozan-etarsko ulje kima i hitozan-etarsko ulje kima-pčelinji vosak. Paralelno sa pripremom filmova, proizvedeni su i odgovarajući kolagen-hitozan laminirani omotači. U pripremi filmova i omotača su primenjena dva vlažna postupka. Filmovi su dobijeni razlivanjem, a laminirani omotači premazivanjem filmogene emulzije preko kolagenog omotača. Tokom razvijanja, ispitivan je uticaj različitih parametara na svojstva dobijenih filmova: viskozitet i koncentracija hitozana, dodatak polietilenoksida kao kopolimera u film, dodatak različite koncentracije etarskog ulja, uslovi me&scaron;anja i temperature, kao i dodatak različite koncentracije pčelinjeg voska.<br />Dobijeni filmovi i omotači su okarakterisani ispitivanjem osobina značajnih za primenu materijala, a to su fizičko-mehanička (debljina, zatezna jačina i izduženje pri kidanju), strukturna (ATR-FTIR spektrometrija i elektron skenirajuća mikroskopija), fizičko-hemijska (sadržaj vlage, bubrenje, rastvaranje), barijerna (propustljivost gasova i brzina propustljivosti vodene pare) svojstva i biolo&scaron;ka aktivnost (antioksidatino i antimikrobno delovanje). Na osnovu detaljne karakterizacije, odabrani su filmovi i omotači optimalnih svojstava za primenu u za&scaron;titi Petrovačke kobasice tokom skladi&scaron;tenja.<br />Ispitano je dejstvo premaza na očuvanje kobasice sa i bez dodate komercijalne i autohtone starter kulture. Efekat primene premaza izučavan je ispitivanjima parametara kvaliteta Petrovačke kobasice i to, praćenjem promene sadržaja vlage, pH vrednosti, boje, oksidacije lipida, kao i senzorne ocene mirisa i ukusa ove kobasice tokom skladi&scaron;tenja.<br />Na osnovu prikazanih rezultata, može se zaključiti da je sintetisan aktivan jestivi premaz na bazi hitozana optimizovanih barijernih, fizičko-hemijskih, antioksidativnih i antimikrobnih svojstava. Sintetisani premaz ima manju brzinu propustljivosti vodene pare, uz očuvanu nisku propustljivost za gasove, smanjenu osetljivost na delovanje vlage i izraženiju antimikrobnu i antioksidativnu aktivnost. Upkos optimizovanim barijernim svojstvima za vodenu paru, hitozanski premaz sa dodatkom etarskih ulja i/ili pčelinjeg voska nije imao efekta u očuvanju sadržaja vlage suve fermentisane kobasice tokom skladi&scaron;tenja. Ispitivani premazi su doprineli očuvanju boje preseka kobasice, ali ovaj efekat nije bio potpuno izražen kod svih tipova kobasice i svih premaza. Sva tri parametra za praćenje oksidativnih promena u kobasici ukazuju na to da je nano&scaron;enjem hitozanskog premaza sa etarskim uljem origana ili kima i pčelinjim voskom, kobasica efikasno za&scaron;tićena od nepoželjnih oksidativnih promena. Između eksperimenata se može povući paralela, da hitozanski premaz pokazuje za&scaron;titni efekat prema senzornom profilu mirisa i ukusa, do blizu 5 meseci skladi&scaron;tenja. Na ovom nivou razvoja premaza, on se može preporučiti kao pomoćan ambalažni materijal.</p> / <p>The subject of the doctoral dissertation is development of active edible coating based on chitosan with added herb essential oils and beeswax, as well as its application for dry fermented sausage shelf life extension.<br />In order to realize the program of investigation, three basic groups of films were produced: chitosan-essential oil of oregano, chitosan-essential oil of caraway and chitosan-essential oil of caraway-beeswax. Simultaneously with the production of films, collagen-chitosan laminated casings were produced. In the production of films and laminated casings, two wet methods were applied. Films were produced by casting method, while laminated casings were produced by coating collagen casing with filmogenic emulsion. During production, the influence of different parameters on properties of produced films and casings was investigated: viscosity and concentration of chitosan, addition of poly (ethylene oxide) as copolymer in the films, addition of different concentration of essential oils, mixing and temperature conditions, as well as addition of different concentration of beeswax.<br />Produced films and laminated casings were characterized by the investigation of properties that are important for material application, namely physical-mechanical (thickness, tensile strength and elongation at break), structural (ATR-FTIR spectrometry and scanning electron microscopy), physical-chemical (water content, swelling, solubility), barrier (gas permeability and water vapor transmission rate) properties and biological activity (antioxidative and antimicrobial activity). Based on detail characterization, films and casings with optimal properties were selected for application on Petrovac sausage with and without the addition af commercial or indigenous starter culture for preservation during storage.<br />The effect of coating application was analyzed based on the quality parameters of Petrovac sausage, namely: water content, pH value, color, lipid oxidation and sensory profile of taste and odor of the sausage during storage.<br />Based on presented results, it can be concluded that active edible coating based on chitosan was synthesized, with optimized barrier, physical-chemical, antioxidant and antibacterial properties. Synthesized coating has lower water transmission rate with preserved low gas permeability, lowered sensibility to humidity and more pronounced antimicrobial and antioxidant activity. Despite optimized water vapor barrier properties, chitosan coating with addition of essential oils and/or beeswax did not show the effect in preserving the water content in the sausage during storage. Investigated coatings contributed to the preservation of core color of the sausage, but this effect was not fully expressed in all types of sausages and coatings. All three parameters for investigation of oxidative changes in the sausage showed that chitosan coating with essential oils of oregano and caraway and beeswax efficiently preserved sausage from unwanted oxidative changes. Mutual conclusion from the experiments is that chitosan coating shows preservative effect on the sensory profile of taste and odor till approximately 5 months of storage. On this level of coating development, it can be recommended as auxiliary packaging material.</p>

The synthetic biodegradable polymer poly(lactide-co-glycolide) (PLGA) has been widely explored as substrate biomaterials for controlled drug delivery and tissue engineering. ECM component heparin and bone mineral hydroxyapatite (HA) are attractive biomaterials which can functionalize the PLGA surface to improve cell cell response and to bring in the dual growth factor delivery, because heparin and HA both can improve cell responses and bind with various proteins. To combine the osteoconductivity of HA and the controlled drug release of PLGA microspheres, HA coated PLGA microspheres were developed by a 3 hour rapid HA precipitation on the PLGA microsphere surface. Effects of various fabrication parameters on microsphere and HA coating morphology were evaluated. This core-shell composite worked as a dual drug delivery device and demonstrated better cell cell response than PLGA microspheres without HA coating. Three different methods, including osmogen, extractable porogen and gas-foaming porogen, were evaluated to fabricate porous microspheres as injectable cell scaffolds in the tissue engineering. The gas-foaming method produced covered porous PLGA microspheres, on which a skin layer covered all the surface pores. The skin layer was hydrolysed by NaOH to control the surface porosity. The modified open porous microspheres have large continued surface areas between pores, which provided more continued areas for cell adhesion. The porous microspheres with controllable surface porosity and large surface continuity between pores could be novel injectable cell scaffolds. Heparin was immobilized on the open porous PLGA microspheres by a facile layer-by-layer assemble to combine the advantages of porous structure and the protein binding from heparin. The heparin-coated porous microspheres promoted cell adhesion, spreading, proliferation and osteogenic differentiation. Growth factor-like protein lactoferrin was immobilized on the heparin coated porous microspheres, which further enhanced MG-63 proliferation and osteogenic differentiation. The heparin-coated porous microspheres are promising multi-functional devices for controlled drug delivery and injectable cell delivery.