Tesis por compendio / This PhD dissertation focuses on the development of renewable and biodegradable active films based on chemically-modified wheat gliadin proteins endowed with antimicrobial capacity owing to the incorporation of naturally-occurring bioactive compounds, namely cinnamaldehyde, natamycin, and lysozyme. Gliadin proteins were treated with cinnamaldehyde at acidic pH and films were produced by casting. The resulting protein-based films presented improved functional properties (mechanical, barrier, and water resistance), and biochemical evidence of the formation of a more compact network whose degree of cross-linking increased with the amount of cinnamaldehyde incorporated into the gliadin-ethanolic solution. Free cinnamaldehyde not participating in the cross-linked reaction remained entrapped in the protein matrix at low relative humidity conditions. The sensitivity of the films to moisture owing to the hydrophilic character of gliadins provided a trigger and control mechanism for the release of cinnamaldehyde in moderate and high relative humidity environments, similar to conditions occurring in packaged food products. The antimicrobial properties of the films developed were tested in vitro by vapor diffusion assays against common food spoilage fungi (Penicillium expansum and Aspergillus niger), showing great effectiveness. Application of these active films to the preservation of two foodstuffs, sliced bread and cheese spread, gave promising results, lengthening fungal growth lag phase and minimizing fungal growth extension. / Balaguer Grimaldo, MDLP. (2015). Development of active bioplastics based on wheat proteins and natural antimicrobials for food packaging applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48520 / Premios Extraordinarios de tesis doctorales / Compendio

Tesis por compendio / [ES] El uso masivo de plásticos sintéticos y su impacto medioambiental obliga a buscar alternativas biodegradables para el envasado de los alimentos,etapa necesaria para su adecuada conservación.Así mismo,la necesidad de incrementar la vida útil de los alimentos ha despertado gran interés en el desarrollo de materiales activos(antimicrobianos y antioxidantes)que mantengan su calidad y seguridad por más tiempo,mediante el uso de compuestos de origen natural,seguros para el consumidor.En este sentido,el desarrollo de materiales biodegradables activos para el envasado de alimentos constituye hoy en día un reto importante para la industria alimentaria.En la presente Tesis Doctoral,se ha estudiado la encapsulación de carvacrol mediante el electroestirado o extensión y secado de diferentes disoluciones poliméricas con carvacrol.Se han utilizado polímeros biodegradables portadores de diferente polaridad(almidón termoplástico:TPS,polivinil-alcohol:PVA, policaprolactona:PCL o ácido poliláctico:PLA)disueltos en el solvente adecuado,con el fin de obtener capas activas.Estas capas se han combinado con otras de polímeros con propiedades complementarias,para obtener laminados activos adecuados para el envasado de alimentos.Los laminados combinaron polímeros polares(TPS o PVA)y poliésteres no polares(PCL o PLA)incorporando el carvacrol en una de las capas.Se evaluó la cinética de liberación del activo,así como la acción antimicrobiana de los materiales obtenidos.Los laminados se caracterizaron en su funcionalidad como material de envase(prop. de barrera,mecánicas u ópticas)así como en su estructura y comportamiento térmico.Los estudios de encapsulación revelaron un mayor potencial encapsulante del carvacrol para los polímeros no polares(PCL;PLA),aunque el PVA mostró también una buena afinidad con el compuesto activo.La matriz de PVA mostró una mayor retención de carvacrol mediante electroestirado de sus disoluciones acuosas que por extensión y secado,sin necesidad de adición de tensoactivos como el Tween85.Para la encapsulación en PLA,se usaron mezclas binarias de solventes aptos para contacto con los alimentos(acetato de etilo y DMSO).En este caso,se obtuvo una mayor eficiencia encapsulante del PLA en los materiales obtenidos por extensión y secado que en los electroestirados.La cinética de liberación del carvacrol de las fibras de PCL explicó el mayor efecto antibacteriano contra E.coli,y el escaso efecto antilisteria.La velocidad de liberación del activo aumentó cuando disminuyó la polaridad de los simulantes alimentarios, mostrando una liberación completa en los sistemas apolares,pero solo hasta 75% en los sistemas acuosos,que requerirían una mayor proporción del activo en el envase para potenciar su efectividad.La combinación de láminas de TPS con fibras de PCL cargadas con carvacrol dio lugar a materiales con una permeabilidad al vapor de agua mejorada,en comparación con los films de almidón,sin efectos relevantes sobre las otras propiedades funcionales estudiadas.Cuando los laminados se probaron in vitro contra cepas G(+) y G(-) mostraron un efecto antibacteriano similar al de las fibras de PCL con carvacrol,pero retrasado en el tiempo.Los estudios de desintegración-biodegradación de los laminados almidón-PCL revelaron que las películas con carvacrol afectaron la actividad del inóculo del compost,disminuyendo ligeramente la biodegradabilidad de las películas,pero alcanzando valores de desintegración similares(75-80%)a las muestras libres de carvacrol.Se obtuvieron también laminados de PLA y PVA mediante la extensión y secado de disoluciones acuosas de PVA con carvacrol.La superficie del PLA fue sometida a aminolización a fin de mejorar la extensibilidad de las disoluciones acuosas.A pesar del incremento de la componente polar de la energía superficial del PLA y su mejorada humectabilidad con las soluciones de PVA,estas bicapas no mostraron una mejora significativa en las propied / [CA] L'ús massiu de plàstics sintètics i el seu impacte mediambiental obliga a buscar alternatives biodegradables per a l'envasament dels aliments necessari per a la seua conservació.Així mateix,la necessitat d'incrementar la vida útil dels aliments ha despertat gran interés en el desenvolupament de materials actius(antimicrobians i antioxidants)que mantinguen la seua qualitat i seguretat per més temps,per mitjà de l'ús de compostos d'origen natural,segurs per al consumidor.En este sentit,el desenvolupament de materials biodegradables actius per a l'envasament d'aliments constituïx un repte important per a la indústria alimentària.En la present Tesi Doctoral,s'ha estudiat l'encapsulació de carvacrol per mitjà de l'electroestirat o extensió i assecat de diferents dissolucions polimèriques amb carvacrol.S'han utilitzat polímers biodegradables portadors de diferent polaritat(midó termoplàstic:TPS, polivinil-alcohol:PVA, policaprolactona:PCL o àcid poliláctic:PLA)dissolts en el solvent adequat,a fi d'obtindre capes actives.Estes s'han combinat amb altres de polímers amb propietats complementàries,per a obtindre laminats actius adequats per a l'envasament d'aliments.Els laminats van combinar polímers polars(TPS o PVA)i poliésters no polars(PCL o PLA)incorporant el carvacrol en una de les capes.Es va avaluar la cinètica d'alliberament de l'actiu,així com l'acció antimicrobiana dels materials obtinguts.Els laminats es van caracteritzar en la seua funcionalitat com a material d'envàs(propietats de barrera, mecàniques o òptiques),així com en la seua estructura i comportament tèrmic.Els estudis d'encapsulació van revelar un major potencial encapsulant del carvacrol per als polímers no polars(PCL i PLA),encara que el PVA va mostrar també una bona afinitat amb el compost actiu.La matriu de PVA va mostrar una major retenció de carvacrol per mitjà d'electroestirat de les seues dissolucions aquoses que per extensió i assecat,sense necessitat d'addició de tensioactius com el Tween 85.Per a l'encapsulació en PLA,es van usar mescles binàries de solvents aptes per a contacte amb els aliments(acetat d'etil i DMSO).Es va obtindre una major eficiència encapsulant del PLA en els materials obtinguts per extensió i assecat que en els electroestirats.La cinètica d'alliberament del carvacrol de les fibres de PCL va explicar el major efecte antibacterià contra Escherichia coli,i l'escàs efecte antilisteria.La velocitat d'alliberament de l'actiu va augmentar quan va disminuir la polaritat dels simulants alimentaris,mostrant un alliberament complet en els sistemes no polars, però només fins a un 75% en els sistemes aquosos,que requeririen una major proporció de l'actiu en l'envàs per a potenciar la seua efectivitat.La combinació de làmines de TPS amb fibres de PCL carregades amb carvacrol va donar lloc a materials amb una permeabilitat al vapor d'aigua millorada,en comparació amb els films de midó, sense efectes rellevants sobre les altres propietats funcionals.Quan els laminats es van provar in vitro contra ceps Gram(+) i Gram(-) van mostrar un efecte antibacterià semblant al de les fibres de PCL amb carvacrol,però retardat en el temps.Els estudis de desintegració-biodegradació dels laminats midó-PCL van revelar que les pel·lícules amb carvacrol van afectar l'activitat de l'inocule del compost,disminuint lleugerament la biodegradabilitat,però aconseguint valors de desintegració semblants(75-80%)a les mostres lliures de carvacrol.Es van obtindre també laminats de PLA i PVA per mitjà de l'extensió i assecat de dissolucions aquoses de PVA amb carvacrol.La superfície del PLA va ser sotmesa a aminolizatció a fi de millorar l'extensibilitat de les dissolucions aquoses.A pesar de l'increment de la component polar de l'energia superficial del PLA i la seua millorada mullabilitat amb les solucions de PVA,estes bicapes no van mostrar una millora significativa en les propietats mecàniques i de barrera / [EN] The massive use of synthetic plastics and their environmental impact makes necessary the search for biodegradable alternatives for food packaging. Likewise, the need to increase the shelf life of food has aroused great interest in the development of active materials (antimicrobial and antioxidant) that maintain food quality and safety for longer periods of time through the use of compounds of natural origin, safe for the consumer. In this sense, the development of active biodegradable materials for food packaging is both a major imperative and challenge for the food industry today. In the present Doctoral Thesis, the encapsulation of carvacrol has been studied by means of the electrospinning or casting of different polymeric solutions with carvacrol. Biodegradable polymers with different polarities (thermoplastic starch: TPS, poly(vinyl-alcohol): PVA, poly-(¿-caprolactone): PCL or poly(lactic acid): PLA) dissolved in the appropriate solvent have been used to obtain active layers. These have been combined with other polymers with complementary properties, to obtain active laminates suitable for food packaging. The laminates combined polar polymers (TPS or PVA) and non-polar polyesters (PCL or PLA) incorporating carvacrol in one of the layers. The release kinetics of the active ingredient was evaluated, as well as the antimicrobial action of the materials obtained. The laminates were characterized in their functionality as a packaging material (barrier, mechanical or optical properties), as well as in their structure and thermal behaviour. Encapsulation studies revealed a higher encapsulating potential of carvacrol for non-polar polymers (PCL and PLA), although PVA also showed a good affinity with the active compound. The PVA matrix showed a higher retention of carvacrol by electrospinning of its aqueous solutions than by casting, without the need for addition of surfactants such as Tween 85. For the encapsulation in PLA, binary mixtures of solvents suitable for food contact (ethyl acetate and DMSO) were used. A higher encapsulation efficiency of PLA was obtained in the materials produced by casting than by electrospinning. The carvacrol release kinetics of PCL fibres explained the higher antibacterial effect against Escherichia coli and the lower antilisterial effect. The release ratio of the active ingredient increased when the polarity of the food simulants decreased, showing a complete release in non-polar systems and only up to 75% in aqueous systems that would require a higher proportion of the active ingredient in the packaging material to enhance its effectiveness. The combination of TPS films with carvacrol loaded PCL fibres resulted in materials with improved water vapour permeabilities, compared to starch films, with no relevant effects on the other functional properties. When the laminates were tested in vitro against Gram (+) and Gram (-) strains, they showed a similar antibacterial effect to that of PCL fibres with carvacrol, but delayed in time. Disintegration-biodegradation studies of PCL-starch laminates revealed that carvacrol films affected the activity of the compost inoculum, slightly decreasing the biodegradability of the laminates, but reaching similar disintegration values (75-80%) to the carvacrol-free samples. PLA and PVA laminates were also obtained by casting aqueous PVA solutions with carvacrol. The surface of PLA was submitted to aminolization in order to improve the extensibility of the aqueous solutions. Despite the increase in the polar component of the PLA surface energy and its improved wettability with PVA solutions, these bilayers did not show significant improvement in mechanical and barrier properties over the PLA monolayers. / The authors would like to thank the Ministerio de Economia y Competitividad of Spain, for funding this study as part of projects AGL2013-42989-R and AGL2016-76699-R and predoctoral research grant # BES-2014-068100. / Tampau, A. (2020). Carvacrol encapsulation by electrospinning or solvent casting to obtain biodegradable multilayer active films for food packaging applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/140313 / Compendio

Tesis por compendio / El desarrollo de materiales de envase biodegradables activos es uno de los retos de la sociedad para resolver los problemas medioambientales asociados a los residuos plásticos y mejorar la conservación de los alimentos, alargando su vida útil. En la presente Tesis Doctoral, se han analizado diferentes estrategias para la obtención y caracterización de películas biodegradables a base de hidrocoloides (almidón de yuca (A) y quitosano (Q)) con características antimicrobianas. Se obtuvieron películas bioactivas gracias a la incorporación de aceites esenciales de capacidad antimicrobiana comprobada: hoja de canela (AC), orégano (AO) y eugenol (EU). Los agentes activos se incorporaron en la matriz polimérica de quitosano por homogenización o encapsulación en liposomas de lecitina o microesferas de alginato, y las películas se obtuvieron mediante casting. Las propiedades fisicoquímicas de las películas se analizaron en función de su composición, así como su actividad antimicrobiana mediante análisis in vitro e in vivo. Se obtuvieron películas por termo- compresión, a base de mezclas A-Q, con dos proporciones polímeros: plastificante (70:30 y 60:40). Las propiedades estructurales, térmicas y físicas de las películas de almidón de yuca obtenidas se vieron afectadas por la incorporación de Q y la proporción polímero: plastificante. Las películas con la mayor proporción de plastificante tuvieron mayor contenido en humedad y fueron más permeables al vapor de agua, menos rígidas y menos resistentes a la rotura. La incorporación de Q tuvo un efecto positivo sobre las propiedades mecánicas de las películas, que aumentaron su rigidez y resistencia a la fractura, reduciéndose su extensibilidad. Sin embargo, el A y Q presentaron una miscibilidad limitada por mezclado en fundido, y las películas exhibieron una estructura heterogénea. A su vez, el polietilenglicol se cristalizó en gran medida en las películas, lo que limitó su efecto plastificante. La incorporación de quitosano proporcionó a las películas sólo una ligera actividad antimicrobiana. Se obtuvieron películas bicapa por procesado en seco de A y vertido/secado de una capa de Q. Ambos polímeros mostraron buena adhesión interfacial, y las bicapas mostraron mejor resistencia mecánica que las monocapas de almidón, aunque fueron menos extensibles debido al efecto de la interfase sobre la fractura. El quitosano fue efectivo en el control del crecimiento bacteriano en carne picada de cerdo, aunque su eficiencia se vio reducida debido al tratamiento térmico en las bicapas, lo que parece indicar la pérdida de grupos amino durante el tratamiento. La incorporación de los aceites esenciales (AC y AO) no mejoró la acción antimicrobiana en las monocapas y bicapas de CH al aplicarse sobre carne de cerdo picada. Se incorporaron aceite esencial de hoja de canela (AC) y eugenol (EU) en películas de Q utilizando nanoliposomas de lecitina. La encapsulación permitió una elevada proporción de retención de compuestos volátiles. La migración total de las películas en simulantes hidrofílicos superó el límite legal establecido para materiales de envase en contacto con alimentos. Sin embargo, la encapsulación en nanoliposomas redujo la migración en todos los simulantes. En ensayos in vitro de eficacia antimicrobiana, todas las películas fueron efectivas frente a L. innocua y E. coli, sin efecto significativo del compuesto activo ni del modo de incorporación. Sin embargo, la encapsulación propició una liberación controlada y sostenida en el tiempo en muestras de carne de cerdo almacenadas durante 13 días a 10 ºC. Se obtuvieron microesferas de alginato con eugenol y se incorporaron en películas de quitosano, cuyas propiedades físicas y estructurales se vieron afectadas. Las microesferas fueron visibles en la estructura de las películas por SEM. La incorporación de las microesfereas promovió una mejora significativa en las propiedad / El desenvolupament de materials d'envàs biodegradables actius és un dels reptes de la societat per a resoldre els problemes mediambientals associats als residus plàstics i millorar la conservació dels aliments, allargant la seua vida útil. En la present Tesi Doctoral, s'han analitzat diferents estratègies per a l'obtenció i caracterització de pel·lícules biodegradables de hidrocoloids (midó de mandioca i quitosano amb característiques antimicrobianes. Es van obtenir pel·lícules bioactives gràcies a la incorporació d'olis essencials de capacitat antimicrobiana comprovada: fulla de canyella (AC), orenga (AO) i eugenol (EU). Els agents actius es van incorporar en la matriu polimèrica de quitosano per homogenització o encapsulació en liposomes de lecitina o microesferes d'alginato, i les pel·lícules es van obtenir per "casting". Les propietats fisicoquímiques de les pel·lícules es van analitzar en funció de la seua composició, així com la seua activitat antimicrobiana mitjançant anàlisi in vitro i in vivo. Es van obtenir pel·lícules per termo- compressió de mescles midó-quitosano, amb dues proporcions polímers:plastificant (70:30 i 60:40). Les propietats estructurals, tèrmiques i físiques de les pel·lícules de midó de yuca obtingudes es van veure afectades per la incorporació de quitosano i la proporció polímer:plastificant. Les pel·lícules amb la major proporció de plastificant van tenir major contingut en humitat i van ser més permeables al vapor d'aigua, menys rígides i menys resistents al trencament. La incorporació de quitosano va tenir un efecte positiu sobre les propietats mecàniques de les pel·lícules, que van augmentar la seua rigidesa i resistència a la fractura, reduint-se la seua extensibilitat. No obstant açò, el midó i quitosano van presentar una miscibilidad limitada per termoprocessat, i les pel·lícules van exhibir una estructura heterogènia. El polietilenglicol va cristal·litzar en gran manera en les pel·lícules, la qual cosa va limitar el seu efecte plastificant. La incorporació de quitosano va proporcionar a les pel·lícules només una lleugera activitat antimicrobiana. Es van obtenir pel·lícules bicapa formades per una capa de midó obtinguda per processament en sec i un altra capa de quitosano obtinguda per "casting". Tots dos polímers van mostrar bona adhesió interfacial, i les bicapes van mostrar millor resistència mecànica que les monocapes de midó, encara que van ser menys extensibles a causa de l'efecte de la interfase sobre la fractura. El quitosano va ser efectiu en el control del creixement bacterià en carn picada de porc, encara que la seua eficiència es va veure reduïda a causa del tractament tèrmic en les bicapes, la qual cosa sembla indicar la pèrdua de grups amino durant el tractament. La incorporació dels olis essencials (AC i AO) no va millorar l'acció antimicrobiana en les monocapes i bicapes de CH en aplicar-se sobre carn de porc. Es van incorporar oli essencial de fulla de canyella (AC) i eugenol (EU) en pel·lícules de quitosano utilitzant nanoliposomes de lecitina. L'encapsulació va permetre una elevada proporció de retenció de compostos volàtils. La migració total de les pel·lícules en simulants hidrofílics va superar el límit legal establert per a materials d'envàs en contacte amb aliments. No obstant açò, l'encapsulació en nanoliposomes va reduir la migració en tots els simulants. En assajos in vitro d'eficàcia antimicrobiana, totes les pel·lícules van ser efectives enfront de L. innocua i E. coli, sense efecte significatiu del compost actiu ni de la manera d'incorporació. No obstant açò, l'encapsulació va propiciar un alliberament controlat i sostinguda en el temps en mostres de carn de porc emmagatzemades durant 13 dies a 10 ºC. Es van obtenir microesferes d'alginato amb eugenol i es van incorporar en pel·lícules de quitosano, les propietats físiques i estructurals de les quals es v / Valencia Sullca, CE. (2017). Different strategies to obtain antimicrobial biodegradable films for food applications, using starch and/or chitosan with or without essential oils [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/89094 / Compendio

Magnesium composites have the potential to be used within the medical setting as a material, particularly for bone implants. Their potential comes from their possession of biodegradability characteristics and material properties that resemble the cortical bone. The biodegradability of the magnesium biomaterials can reduce the need for a second surgery to remove implants when a level of bone regeneration is reached to be self-sufficient, therefore removing the dependency on the implant. However, magnesium in its naturally occurring state demonstrates high corrosivity and degradation when simulated in a biological context. We investigate a magnesium composite (magnesium-bioglass) by testing biodegradation and mechanical properties, evaluating the differences in properties when compared to the mechanical properties of pure magnesium, and analyzing scanning electron microscopy results applied to samples immersed in a solution to simulate the in vivo setting. Through the various modes of fabrication of the magnesium composites, increased bioactivity can be measured. The results support the potential of using the bioactive magnesium-bioglass composites for orthopedic implants.

Terrestrial microplastics are increasing in abundance and are an emerging contaminant of concern, particularly in agriculture ecosystems where plastic use and subsequent soil contamination are prevalent. Plastic film mulches make up a significant portion of the plasticulture industry and are directly linked to soil microplastic pollution where negative effects to soil biotic and abiotic functions have been observed. In response to this issue, biodegradable film mulches have been promoted as a sustainable alternative to conventional polyethylene-based mulches. These biodegradable mulches, composed of various bioplastics, are designed to be tilled back into the soil where they are expected to decompose. However, the degradation of biodegradable film mulches has proven to be inconsistent and unpredictable, potentially leading to the persistence of micro-bioplastic (MBP) particles in the soil that may cause adverse effects like those of microplastics from conventional mulches. To evaluate the efficacy of this novel technology as a viable alternative to conventional plastic mulches, this 2-month incubation study examined the effects of MBPs derived from polybutylene adipate terephthalate (PBAT)-based biodegradable mulch on a suite of soil health indicators. Using laboratory-prepared soils, the study assessed how clay mineralogy and organic matter content influence soil-MBP interactions under controlled conditions. Our results suggest there is a significant effect of MBPs on soil moisture and nutrient cycling with a potential negative priming effect, particularly in soils where organic matter is limited. Additionally, clay mineralogy significantly mediated soil-MBP interactions. While MBP presence altered C pools, a qualitative analysis suggests the MBP particles remained largely undegraded by the end of the incubation period. These findings suggest that MBPs have the potential to influence soil properties and functions, underscoring the need for further research to fully understand their environmental implications in field conditions.

Assimilable organic carbon (AOC) is a suspected contributor to growth of microbes, including pathogens, in plumbing systems. Two phases of research were completed to improve knowledge of AOC and other forms of organic carbon in premise plumbing. In the first phase, the AOC Standard Method 9217B was compared to a new luminescence-based AOC in terms of time, cost, convenience, and sources of error. The luminescence method was generally more accurate, as it better captured the peak growth of the test organisms. It was also less expensive and less time-consuming. A few approaches to improving the accuracy of the method and detect possible errors were also presented. In the second phase of research, the possibility of AOC generation in premise plumbing was reviewed and then tested in experiments. It has been hypothesized that removal of AOC entering distribution systems might be a viable control strategy for opportunistic premise plumbing pathogens (OPPPs), but if AOC was generated in premise plumbing systems this approach would be undermined. Possible sources of AOC creation in premise plumbing, which is herein termed "distribution system derived biodegradable organic carbon (DSD-BDOC)," include: leaching of organic matter from cross linked polyethylene (PEX) pipes, autotrophic oxidation of H2 generated from metal corrosion (e.g. sacrificial magnesium anode rods and iron pipes), rendering of humic substances more biodegradable by sorption to oxides such as Fe(OH)3, and accumulation of AOC on filters and sediments. The potential for various plumbing and pipe materials to generate AOC was compared in controlled simulated water heater experiments. Under the worst-case condition, generation up to 645 µg C/L was observed. IT was not possible to directly confirm the biodegradability of the generated organic carbon, and there were generally no correlations between suspected generation of organic carbon and either heterotrophic plate counts (HPC) or of bacterial 16S rRNA genes. DSD-BDOC was also explored in a simulated distribution system with two disinfectant types (chlorine and chloramine) and three pipe materials (PVC, cement, and iron). TOC increased with water age, probably due to leaching of organics from PVC and possibly the aforementioned DSD-BDOC due to autotrophic reactions of nitrifiers and iron-related bacteria. As before, relationships between the higher levels of organic carbon and either HPC or 16S were not observed. / Master of Science

Yes / Binary and ternary blends of a polylactic acid matrix with polycaprolactone (PCL) and polybutylene succinate (PBS) were produced by twin screw extrusion, containing up to 30 wt% loading. Mechanical, thermal and rheological characterisation techniques were used to quantify properties of the different blend formulations and miscibility was investigated using scanning electron microscopy. PCL is known to act as an impact modifier in PLA but to cause a corresponding reduction in strength. Results showed that addition of both PBS and PCL seperatly caused a reduction in melt viscosity, elastic modulus and tensile strength, but an increase in impact strength and strain at break. Analysis of morphology suggested that immiscibility was evident, particularly at higher PCL and PBS loadings. Results indicated that incorporation of a small loading of PBS had a synergistic effect on the PLA-PCL blend properties. Miscibility was improved and enhanced mechanical properties were observed for a ternary blend containing 5 wt% of both PBS and PCL compared to blends containing 10% of each polymer alone. / Financial support of Floreon- Transforming Packaging Ltd through the PhD sponsorship and materials provision.

Polylactic acid (PLA) is an aliphatic polyester, derived from sustainable natural sources that is biodegradable and can be industrially composted. This material has been in the spotlight recently due to its sustainability and properties. However it has been invented in 1932 by Carothers and then patented by DuPont in 1954 (Standau et al. 2019). The properties of this material though limit its use for applications mainly in the medical sector and in some cases single use packaging. In this research, PLA based blends with improved rheological and thermomechanical properties are investigated. The focus is based in proposing strategies in improving these properties based on commercial methods and processing techniques. In this work, commercial grade PLA has been blended with polycaprolactone (PCL) and polybutylene succinate (PBS) in binary and ternary formulations via twin screw extrusion. PCL has been known to act as an impact modifier for PLA, but to cause a corresponding reduction in strength. Results showed that the binary PLA blends containing PBS and PCL, had reduced viscosity, elastic modulus and strength, but increased strain at break and impact strength. Morphological and thermal analysis showed that the immiscibility of these additives with PLA caused these modifications. Incorporation of a small loading of PBS had a synergistic effect on the PLA-PCL blend properties. Miscibility was improved and enhanced mechanical properties were observed for a ternary blend containing 5wt% of both PBS and PCL compared to binary blends containing 10% of each additive. To increase heat resistance of PLA, the material’s crystallinity has to be increased. However PLA has a relatively slow crystallisation rate making it difficult and expensive to be used in commercial applications where heat resistance is needed. For this reason the chiral nature of PLA has been used to investigate the effect of stereochemistry of PLA in crystallisation. Optically pure PDLA was added to its enantiomer in small amounts (up to 15%) and the properties and crystallisation mechanism of these blends was investigated. Results showed that the addition of PDLA accelerated crystallinity and developed a stucture that increased heat resistance, melt strength and stiffness. Finally, a processing model of developing a fully stereocomplex PLA part based in commercial techniques is proposed. Injection moulded PLA showed even higher heat resistance without the need of further processing the product (increasing crystallinity). / Floreon

Researchers are discovering that the lighting sector is placing more of an emphasis on sustainable resources, cutting-edge technology, and ecological responsibility. The challenge facing today's craftsmen is producing functional items that complement urban growth and lifestyle choices.  The thesis project focuses on designing and developing a wall mounted luminaire product integrating modular design using biodegradable materials such as banana fiber, bamboo cane along with wood. Further, the project discovers the possibility of implementing ‘Do it yourself’ system in the product wherein user gets the unique experience of knitting bamboo cane to create patterns and build the whole luminaire product by themselves. Various mockups and test prototypes have been made to investigate pain points and to undertake various design decisions keeping primary focus on ‘Do it yourself’ kit.  The current project also collates business model by designing a single foldable packaging with the short story of the people and the place about the craft training organization. Packaging also comes with a nicely designed user instruction manual along with all the components have been included. Light source will have LED Opal strip with the corelated color temperature of 2700 K, warm chosen for the decorative purpose and to create ambient and cozy atmosphere in the living spaces. The luminaire product overall conveys sustainable design that allows biodegradable materials to be recycled into a new product that encourages the circular economy or be discarded in a landfill after its intended lifespan has been fulfilled.

Biological filtration (Biofiltration) processes have been used first in Europe and then in North America for decades, however currently there is not a good overall parameter to guide biofiltration design and operation except adopting parameters from traditional particle- removal filtration process. On the basis of the biofilm model developed by Rittmann and McCarty (1980a) and the pseudo-analytical solution for the model, Zhang and Huck (1996a) obtained an analytical solution for PF (plug flow) reactors (which can be used for biofilters approximately) after demonstrating that axial dispersion could be reasonably ignored and developed a new parameter, X*, which incorporates considerations of physical contact time, filter media particle size, kinetics, etc. A small-scale application on peers’ engineering/research data by Huck (1999) demonstrated it was a better indicator than other parameters for biofiltration performance. By collecting, screening and investigating literature on AOC, BDOC and odorous compounds removal by biofiltration process, this thesis applied the X* concept to the collected investigations to assess process performances among different target parameters, different filters and different investigations. To the author’s knowledge, this is the first such attempted comprehensive comparison of literature studies, interpreted in terms of a common parameter (X*). The wide ranges of particle sizes, EBCTs, temperatures and high diversity of pre-treatment and operation conditions for the collected cases were considered to be able to well represent biofiltration practices for studied removal targets. No significant relationship between EBCTs and removal percentages were found, indicating that EBCT alone is not able to guide biofiltration design and operation. Based on kinetics parameter comparison, BDOC removal-X* relationship was established. A new parameter, θα, was developed in this thesis to refer to estimated X* values only considering EBCT and particle size. θα parameter values were estimated by comparison of ratios of θα products ((θα)’) based on the properly chosen calculation bases. Distribution of the θα values for temperature-favored (i.e. temperature ≥15°C) AOC and BDOC removal biofiltration processes matched the established removal-X* relationship reasonably. Given the exploratory nature of this research and the complexity of attempting quantitations, fits were assessed based on visual comparison. With the assistance of supporting information and by adopting available temperature activity coefficients, temperature-adjustment coefficients for θα values were determined for the different temperature ranges. Temperature-adjusted AOC and BDOC removal-θα relationships were developed and temperature-adjusted θα parameter values for AOC and BDOC removal were also estimated. Comparisons were conducted, showing fair matches based on visual examinations, for most of the temperature ranges. No relationships were found between ozone dosages and AOC/BDOC removal percentages and the statistical analysis indicated there was significant difference of removal efficiencies between ozonated and non-ozonated influents for biofilters, suggesting ozonation may not only increase the amount of BOM for following biofilter and increase the biodegradability of bulk water; it may also increase the biodegradability of AOC and BDOC themselves. It may not be realistic to obtain the estimated θα values for MIB and geosmin removal by biofiltration. However, plotting θα product vs. removal percentage for the collected MIB and geosmin removal cases shows more positive co-relationships than EBCT-removal percentage relationships visually. A utilization factor η was proposed to guide biofilter design and operation and to assess “over-design” and “under-operated”. Biofilter over-design or under-operated is common for the collected cases. In general, examining X* (or θα, a parameter incorporating the physical components of X*) provided useful information in terms of evaluation and prediction of biodegradable organic compounds removal by biofiltration, which confirms that X* is a better parameter for biofiltration design and operation than other parameters, such as EBCT.