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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

Painel OSB de resíduo de madeira Balsa (Ochroma Pyramidale) / Oriented Strand Board (OSB) of residual Balsa wood (Ochroma Pyramidale)

Hellmeister, Victor 23 November 2017 (has links)
Este trabalho teve como objetivo produzir e ensaiar painéis OSB (Oriented Strand Board) com resíduo de madeira Balsa (Ochroma Pyramidale) proveniente de reflorestamento, aglomerados com resinas uréia-formaldeído (UF), fenol-formaldeido (FF) e poliuretana à base de óleo mamona (PU-Mamona), e os caracterizar por meio de ensaios termo-físico-mecânicos e microestruturais. A escolha da madeira Balsa residual ocorreu devido a fatores como baixa densidade, alta resistência específica, elevada taxa de crescimento e disponibilidade de matéria-prima. Inicialmente as partículas de madeira Balsa foram caracterizadas por ensaios físicos, químicos (densidade por picnometria de gás hélio, pH e composição química) e microestruturais (microscopia eletrônica de varredura - MEV, espectroscopia de infra-vermelho - FTIR, Difração de Raios-X - DRX e termogravimetria - TG). As resinas foram caracterizadas por ensaios microestruturais (DRX, FTIR e TG-DSC). A partir dessas informações foram produzidos painéis de madeira Balsa em escala laboratorial de baixa e média dendidade com partículas do tipo strand de resíduo de madeira Balsa aglomerado com as referidas resinas, os quais foram caracterizados por ensaios físicos (inchamento em espessura, absorção de água e densidade aparente), mecânicos (flexão estática e adesão interna), microestruturais (MEV, FTIR, DRX e TG-DSC) e ensaios de condutividade térmica. Os resultados obtidos foram comparados com as indicações da norma européia EN 300:2006 e indicaram que apenas os painéis OSB de madeira Balsa residual aglomerada com resina poliuretana à base de óleo de mamona atendem os requisitos estabelecidos para painéis OSB de Classe 1 de uso interno e não-estrutural. / The objective of this work was to produce and test OSB (Oriented Strand Board) with residual wood balsa (Ochroma Pyramidale) from reforestation, agglomerated with urea-formaldehyde (UF) resins, phenol-formaldehyde (FF) and oil-based polyurethane castor bean (PU-Mamona), and characterize them by means of thermo-physical-mechanical and microstructural tests. The choice of residual Balsa wood occurred due to factors such as low density, high specific strength, high growth rate and availability of raw material. Initially the particles of Balsa wood were characterized by physical, chemical tests (density by helium gas picnometry, pH and chemical composition) and microstructural (Scanning Electron Microscopy - SEM, infrared spectroscopy - FTIR, X- Ray Diffraction DRX and Thermogravimetry - TG). The resins were characterized by microstructural tests (XRD, FTIR and TG-DSC). Based on this prior information, OSB wood panels were produced in laboratory scale of low and medium density with strand type particles of wood residue Balsa agglomerated with refered resins, which were characterized by physical tests (swelling in thickness, absorption of water and (static flexural and internal adhesion), microstructural (SEM, FTIR, XRD and TG-DSC) and thermal conductivity tests. The results obtained were compared to the European standard EN 300: 2006 and indicated that only OSB panels of wood Residual Balsa agglomerated with polyurethane resin based on castor oil comply with the requirements established for Class 1 OSB panels for internal and non-structural use.
2

Painel OSB de resíduo de madeira Balsa (Ochroma Pyramidale) / Oriented Strand Board (OSB) of residual Balsa wood (Ochroma Pyramidale)

Victor Hellmeister 23 November 2017 (has links)
Este trabalho teve como objetivo produzir e ensaiar painéis OSB (Oriented Strand Board) com resíduo de madeira Balsa (Ochroma Pyramidale) proveniente de reflorestamento, aglomerados com resinas uréia-formaldeído (UF), fenol-formaldeido (FF) e poliuretana à base de óleo mamona (PU-Mamona), e os caracterizar por meio de ensaios termo-físico-mecânicos e microestruturais. A escolha da madeira Balsa residual ocorreu devido a fatores como baixa densidade, alta resistência específica, elevada taxa de crescimento e disponibilidade de matéria-prima. Inicialmente as partículas de madeira Balsa foram caracterizadas por ensaios físicos, químicos (densidade por picnometria de gás hélio, pH e composição química) e microestruturais (microscopia eletrônica de varredura - MEV, espectroscopia de infra-vermelho - FTIR, Difração de Raios-X - DRX e termogravimetria - TG). As resinas foram caracterizadas por ensaios microestruturais (DRX, FTIR e TG-DSC). A partir dessas informações foram produzidos painéis de madeira Balsa em escala laboratorial de baixa e média dendidade com partículas do tipo strand de resíduo de madeira Balsa aglomerado com as referidas resinas, os quais foram caracterizados por ensaios físicos (inchamento em espessura, absorção de água e densidade aparente), mecânicos (flexão estática e adesão interna), microestruturais (MEV, FTIR, DRX e TG-DSC) e ensaios de condutividade térmica. Os resultados obtidos foram comparados com as indicações da norma européia EN 300:2006 e indicaram que apenas os painéis OSB de madeira Balsa residual aglomerada com resina poliuretana à base de óleo de mamona atendem os requisitos estabelecidos para painéis OSB de Classe 1 de uso interno e não-estrutural. / The objective of this work was to produce and test OSB (Oriented Strand Board) with residual wood balsa (Ochroma Pyramidale) from reforestation, agglomerated with urea-formaldehyde (UF) resins, phenol-formaldehyde (FF) and oil-based polyurethane castor bean (PU-Mamona), and characterize them by means of thermo-physical-mechanical and microstructural tests. The choice of residual Balsa wood occurred due to factors such as low density, high specific strength, high growth rate and availability of raw material. Initially the particles of Balsa wood were characterized by physical, chemical tests (density by helium gas picnometry, pH and chemical composition) and microstructural (Scanning Electron Microscopy - SEM, infrared spectroscopy - FTIR, X- Ray Diffraction DRX and Thermogravimetry - TG). The resins were characterized by microstructural tests (XRD, FTIR and TG-DSC). Based on this prior information, OSB wood panels were produced in laboratory scale of low and medium density with strand type particles of wood residue Balsa agglomerated with refered resins, which were characterized by physical tests (swelling in thickness, absorption of water and (static flexural and internal adhesion), microstructural (SEM, FTIR, XRD and TG-DSC) and thermal conductivity tests. The results obtained were compared to the European standard EN 300: 2006 and indicated that only OSB panels of wood Residual Balsa agglomerated with polyurethane resin based on castor oil comply with the requirements established for Class 1 OSB panels for internal and non-structural use.
3

Development of a Humidity-Resistant Coating to Impart High Oxygen Barrier Performance to Food Packaging Films

Cox, Ryan Yinghua 01 June 2017 (has links)
Oxygen barrier coatings have the potential to greatly extend the lifetime of certain food products by incorporating them into existing food packaging. Present technologies face definite challenges of maintaining high performance, while attaining simple and inexpensive preparation methods. The oxygen barrier effect obtained with these coatings is also susceptible to a plasticization effect when exposed to high humidity, since water vapor molecules are readily soluble in typically hydrophilic resins. In this work, we demonstrate a 1 – 2 micron thick oxygen barrier coating, prepared on a 12 micron poly(ethylene terephthalate) substrate, that has oxygen transmission rates as low as 1.44 cc m-2 day-1 under standard conditions and can maintain similar oxygen barrier performance at high humidity. This degree of oxygen barrier meets the standard of 1 – 10 cc m-2 day-1 established for food packaging applications. The coating is prepared through use of sol-gel chemistry between poly(vinyl alcohol) and vinyltrimethoxsilane molecules, which form a strong network resin through hydrolysis and condensation reactions. The formulation of these oxygen barrier coatings allows for variability of solids percentage and viscosity without significant change in performance. The ability to scale up the preparation of these coated films was tested successfully on an industrial flexographic printing press.

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