Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.5/1082
Título: Estudo da molhabilidade da madeira de pinho pela resina ureia-formaldeído
Outros títulos: Study of the wettability of pine wood by urea-formaldehyde resins
Autor: Cruz, Maria Manuela Silva
Orientador: Carvalho, Luísa Maria Hora
Martins, Jorge Manuel Silva
Palavras-chave: madeira de pinho
resina de ureia formaldeido
tensão superficial
aglomerado de particulas
pine wood
urea formaldehyde resins
surface energy
particleboard
Data de Defesa: 2006
Resumo: Wettability phenomena is related to macroscopic manifestations of molecular interaction between liquids and solids interfaces. A better knowledge of these phenomena in wood is important to improve the capacity of interaction between wood and adhesives in applications involving gluing, because a good wettabilty is crucial for a good adhesion. The main objective of this work was to study the wettability of pine (Pinus Pinaster) and eucalypt (Eucalyptus Globulus), subjected to different treatments using urea-formaldehyde resins of different composition with the aim of improving bonding in the production of particleboard. Pine and eucalypt logs were collected at the wood-yard of a particleboard plant, including burned wood from forest fires, representing the major wood supply used in Portugal. Several wood samples were subjected to different treatments (over-drying, extraction with water and ageing under sunlight), similar to those of the industrial process. In a first approach, the surface tension of wood was determined using the acid-base theory and the influence of wood species and treatments on the total surface tension and Lifshitz-van der Waals (LW) and acid-base components was evaluated. Then, in order to compare the ability of three resin formulations for bonding wood of these species, measurements of contact angle of these resins and mechanical tests were carried out in fresh wood samples and in samples subjected to the treatments. The influence of several factors and levels on wettability and bond strength, were analysed using ANOVA: two species, sapwood/heartwood, burned/normal wood, three treatments and three commercial resins.
Descrição: Mestrado em Engenharia de Materiais Lenhocelulósicos - Instituto Superior de Agronomia
URI: http://hdl.handle.net/10400.5/1082
Aparece nas colecções:BISA - Dissertações de Mestrado / Master Thesis

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