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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Biodegradable packaging for corrosion inhibition via supercriticial fluid

Leavitt, Leah A., January 2007 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on December 28, 2007) Includes bibliographical references.
2

Synthesis, Characterization, and Cyclic Stress Influenced Degradation of a Poly(Ethylene) Glycol Based Poly(Beta-Amino Ester)

Keim, Terra Ann 23 August 2007 (has links)
Poly(beta-amino esters) are photopolymerizable and biodegradable polymers prepared by the combination of amines with diacrylates. This study aims to fundamentally understand the polymer network formed by poly(ethylene)glycol diacrylate (PEGDA) MW 700 and 3-methoxypropylamine (3MOPA) as well as to characterize the degradation response of this material with and without cyclic loading. The networks were formed by a two-step process; (1) the synthesis of amine-co-peg diacrylate macromers through a step growth reaction, followed by (2) UV initiated chain growth network formation of the diacrylated macromers. Macromer reaction chemistry was confirmed by 1H NMR measurements. UV calorimetric analysis revealed that network formation was dependent on molecular weight of the PEGDA monomer and light intensity, but not temperature in the range of 20 °C to 40 °C. The glass transition temperature of all networks was measured to be in the range of -40 °C to -30°C with a rubbery moduli ranging from 4 to 10 MPa, depending on the molecular weight of the PEGDA monomer. Partial crystallization was discovered to occur in the networks containing higher molecular weight PEGDA only in the presence of humidity and high frequency cyclic loading. Degradation studies were performed with and without applied cyclical stress, and in both cases elastic modulus decrease and mass loss occurred steadily over a 24-hour period. Increasing frequency of applied compressive stress during degradation served to slightly lower degradation rates, especially in samples cycled at high frequency, which crystallized. In all materials, applied cyclic load resulted in catastrophic fracture of the material prior to an appreciable decrease in modulus. The experiments reveal that degradation rate and failure mode can be influenced by the addition of cyclic loading and this should be considered when screening biodegradable polymers for applications that include mechanical loading.
3

Fabrication of PHBV and PHBV-based composite tissue engineering scaffolds through the emulsion freezing/freeze-drying process and evaluation of the scaffolds

Sultana, Naznin. January 2009 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 253-274). Also available in print.
4

Fabrication of PHBV and PHBV-based composite tissue engineering scaffolds through the emulsion freezing/freeze-drying process andevaluation of the scaffolds

Sultana, Naznin. January 2009 (has links)
published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy
5

Synthesis, degradation and practical applications of a glycerol/citric acid condensation polymer /

Trenkel-Amoroso, Jan. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 53-54). Also available on the World Wide Web.
6

Fabrication of PHBV and PHBV-based composite tissue engineering scaffolds through the emulsion freezing/freeze-drying process and evaluation of the scaffolds /

Sultana, Naznin. January 2009 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 253-274). Also available online.
7

Enhanced adhesion of biodegradable drug delivery vehicles to inflamed endothelium

Sakhalkar, Harshad S. January 2005 (has links)
Thesis (Ph.D.)--Ohio University, November, 2005. / Title from PDF t.p. Includes bibliographical references (p. 165-167)
8

Sorbetes de Tallo de Trigo Biodegradables: Allihuasi

Jurado Espinoza, Luis Miguel, Lescano Subelete, Lily Laidy, Lopez Vilcas, Carmen Rosa Consuelo, Salazar Caldas, Judith Beylith, Vasquez Julcahuanca, Delmira 05 November 2019 (has links)
El presente proyecto desarrollado durante el ciclo 2019-2, se denomina Allihuasi, la cual es una empresa que ofrece sorbetes ecológicos y biodegradables a negocios en el sector de bebidas y alimentos para el consumo humano. La idea de negocio surge a partir de las consecuencias del excesivo uso del plástico y por la entrada en vigor de la Ley N°30884, la cual progresivamente busca que las personas y los negocios dejen de usar y comercializar productos de plástico de un solo uso. Por otro lado, para la realización del proyecto se identificaron factores como las preferencias de los clientes por el uso de productos ecológicos y el aumento de uso de productos biodegradables. Allihuasi cuenta con una alianza con los agricultores de trigo, en la cual ambas partes obtienen beneficios. Por un lado, los proveedores generan ingresos por la venta de una materia prima que no utilizan y por el otro, la empresa genera ganancias comercializando sorbetes de trigo. Asimismo, la empresa atiende al segmento de bares en los distritos de Miraflores y Barranco, debido a que están dispuestos a pagar un precio mayor por productos ecológicos de calidad que el segmento de restaurantes o juguerías Al culminar este trabajo de investigación se puede concluir que el negocio puede expandirse a otros sectores como restaurantes de fast food, cadenas de cine y cualquier otro negocio que requiera el uso de sorbetes para sus actividades. Sin embargo, esto se dará a largo plazo, cuando la ley prohíba completamente el uso, comercialización y la fabricación de sorbetes de plástico. / The present project developed during the 2019-2 cycle is called AlliHuasi, a company that offers organic and biodegradable sorbets to companies in the food and beverage sector for human consumption. The business idea arises from the consequences of excessive use of plastic and with the entry into force of Law No. 30884, which progressively seeks that people and companies stop using and marketing single-use plastic products. On the other hand, for the realization of the project were identified factors such as customer preferences for the use of organic products and the increased use of biodegradable products. AlliHuasi has an alliance with wheat producers, in which both parties have benefits. On the one hand, suppliers have income from the sale of a raw material that they do not use and, on the other, the company generates profits by marketing wheat sorbets. Besides, the company also attended the bar segment in the Miraflores and Barranco districts, because they are willing to pay a higher price for quality organic products than the restaurant or stores that sell juices segment. The conclusion of the project is that the business can expand to other sectors such as fast food restaurants, movie chains and any other business that requires the use of sorbets for its activities. However, this will occur in the long term, when the law completely prohibits the use, commercialization and manufacture of plastic sorbets. / Trabajo de investigación
9

Proyecto BioPack. Platos biodegradables / BioPack Project. Biodegradable plates

Aymara Leon, Rossmery Luz, Félix Limas, María del Pilar, Maguiña Quispe, Ginna Alejandra, Ticona Avalos, Nataly, Ventosilla Laverio, Yady Elizabeth 27 November 2019 (has links)
La contaminación ambiental se ha convertido en uno de los problemas sociales más importantes a nivel internacional. Este impacto tiene como causa principal el uso excesivo de plástico, el cual demora en degradarse entre 150 a 1000 años, dependiendo del tipo de producto. En el Perú, el uso promedio de plásticos es de 30 kilogramos por persona al año. Con el fin de poder contribuir con la disminución del uso de plástico de un solo uso y ser una huella de sostenibilidad en el planeta, nace BioPack, una empresa eco-amigable que ofrece platos biodegradables a base de residuos orgánicos, dando un nuevo valor a los productos que ya no se utilizan. En el presente trabajo de investigación, se podrá apreciar el análisis y desarrollo de esta empresa en sus diferentes etapas de evolución. En primer lugar, se presenta el modelo de negocio de BioPack, a través de la herramienta del Business Model Canvas y la validación de cada uno de sus cuadrantes. Seguido de ello, se explica el desarrollo del plan de negocio, mostrando el análisis interno y externo de BioPack. A continuación, se explica el concierge, es decir, la validación de la intención de compra de los usuarios objetivos de la empresa, por medio de ventas reales. Finalmente, se presenta el desarrollo de cinco importantes planes operativos de la empresa. Uno de ellos es el Plan Financiero, uno de los más importantes, debido a que, con este, se concluyó si la empresa era viable y rentable en el tiempo. / Environmental pollution has become one of the most important social problems in the world. This impact has as its main cause the excessive use of plastic, which takes about 150 to 1000 years to degrade, depending on the type of product. In Peru the average use of plastics is 30 kilograms per person per year. In order to contribute to the decrease in the use of single-use plastic and be a mark of sustainability on the planet, BioPack is born, an eco-friendly company that offers biodegradable dishes based of organic waste, giving new value to products that are no longer used. Throughout this research paper, you will appreciate the analysis and development of this company in its different stages of evolution. First, the BioPack business model is presented, through the Business Model Canvas tool and the validation of each of its quadrants. Following this, the development of the business plan is explained, where the internal and external analysis of BioPack is shown. Then, the concierge is explained, that is the validation of the purchase intention of the objective users of the company, through real sales. Finally, the development of five important operational plans of the company is presented, such as the Financial Plan, the latter one of the most important, because, from this, it was concluded if the company was viable and profitable over time. / Trabajo de investigación
10

Synthesis and characterization of a biocomposite derived from banana plants (Musa cavendish)

Paul, Vimla January 2015 (has links)
Submitted in fulfillment of the requirements of the degree of Doctor of Philosophy in Chemistry, Durban University of Technology. Durban, South Africa, 2015. / Over decades synthetic composites have become an indispensable part of our lives with their various applications such as packaging, sporting equipment, agriculture, consumer products, medical applications, building materials, automotive industry, and aerospace materials among others. Although these polymers have the desired properties for the above applications, they are invariably costly. Furthermore, they cannot be easily disposed of at the end of their useful lives and simply pile up and cause significant damage to the environment. However, the dwindling supply of fossil fuel, increased oil prices, together with the growing public concern of greenhouse gas emissions and global warming, has forced scientists to search for new development of sustainable materials from renewable resources. Hence in recent years, there is an increased interest in biocomposite manufacturing with natural resources as environmental issues are addressed. The research work presented in this dissertation is to the best of the author’s knowledge a world-first overall investigation pertaining to the concept of synthesizing a banana sap based bio-resin (BSM) reinforced with banana fibres. In this work the chemical composition of banana sap was determined to investigate the chemical reactions taking place in the resin formulation. BSM was synthesized, characterized and proposed as a potential bio-resin to be used in the biocomposite manufacture for non-functional motor vehicle components. BSM, a hybrid bio-resin was synthesized with equimolar quantities of maleic anhydride and propylene glycol and 50% banana sap. A control resin without the banana sap was also synthesized for comparison purposes. It was proposed that the presence of sugars, esters and pthalates from the sap, determined by HPLC and GC-MS, contributed to the cross-linking of the polymer chain. The acid value and viscosity of BSM were determined and found to be within specification of an industry resin. The molecular weights of the BSM and control resins were 2179 and 2114 units respectively. These were within the required molecular weight of unsaturated polyester resins. The gel and cures times of the BSM were 60% lower than the control resin suggesting that the banana sap behaved as an accelerator for the curing process. The lower cure time meant that using the banana sap in the formulation was cost effective and time saving. The thermal properties of BSM showed improved degradation temperatures and degree of crystallinity compared to the control resin. A parametric study showed that increasing banana sap concentration in the resin formulation led to increased tensile and flexural properties with 50% being the optimum amount of sap to be added to the formulation. The synthesized bio-resin and control resin were applied to biocomposites and characterized in terms of physical, thermal, mechanical, morphological, chemical and biodegradable properties. Mechanical tests indicated a 15 % increase in tensile strength, 12 % improvement in tensile modulus and a 25 % improvement in the flexural modulus, when compared to structures produced without banana sap. Natural fibres present the challenge of poor adhesion to the matrix. Chemical treatment of the banana fibre was done to improve on the compatibility of resin to fibre. Fibre pull-out showed that treated fibres had a better bond than the untreated fibre. Parametric studies were also done to evaluate the effect of fortifying the BSM resin with nanoclay. A 5% clay loading resulted in a 24% increase in tensile strength and 28% increase in flexural properties. Finally biodegradation studies of the BSM bio-resin, BSM biocomposite, control resin and control composite were investigated and compared to a positive reference, cellulose. Results showed that over a period of 55 days the BSM biocomposite showed 17.6% biodegradation compared to 8% with the control composite. No difference in biodegradation between the BSM bio-resin and the control resin was recorded. BSM biocomposite was proposed as a potential replacement to synthetic composites that contribute to the environmental landfill problems. The main contribution of this research is the use of the reinforcement and matrix from the same natural source. An enriched understanding of the synthesis, characterization and performance of the banana sap based bio-resin and biocomposite for the use of non-functional motor vehicle components is the key outcome of this investigation.

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