Thesis (M. Sc.)--University of Manitoba, 1996. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

This labor is based on penetration of adhesives into a wood cell walls. It focuses mainly on adhesives that are currently used for construction purposes. It also contains a methodics of selecting adhesives and wood, which will be used for glued joints and summarizes the methods used for detect these adhesives in the wood cell wall. It experimentally verifies the appropriate selection of the dye-solvent combination used in the adhesive.

No description available.

Lead-tin solder has been widely used as interconnection material in electronics packaging for a long time. In response to environmental legislation, the lead-tin alloys are being replaced with lead-free alloys and electrically conductive adhesives in consumer electronics. Lead-free solder usually require higher reflow temperatures than the traditional lead-tin alloys, which can cause die crack and board warpage in assembly process, thereby impacting the assembly yields. The high tin content in lead-free solder forms tin whiskers, which has the potential to cause short circuits failure. Conductive adhesives are an alternative to solder reflow processing, however, conductive adhesives require up to 80 wt% metal filler to ensure electrical and thermal conductivity. The high loading content degrades the mechanical properties of the polymer matrix and reduces the reliability and assembly yields when compared to soldered assemblies. Carbon nanotubes (CNTs) have ultra high aspect ratio as well as many novel properties. The high aspect ratio of CNTs makes them easy to form percolation at low loading and together with other novel properties make it possible to provide electrical and thermal conductivity for the polymer matrix while maintaining or even reinforcing the mechanical properties. Replacing the metal particles with CNTs in conductive adhesive compositions has the potential benefits of being lead free, low process temperature, corrosion resistant, electrically/thermally conductive, high mechanical strength and lightweight. In this paper, multiwall nanotubes (MWNTs) with different dimensions are mixed with epoxy. The relationships among MWNTs dimension, volume resistivity and thermal conductivity of the composite are characterized. Different loadings of CNTs, additives and mixing methods were used to achieve satisfying electrical and mechanical properties and pot life. Different assembly technologies such as pressure dispensing, screen and stencil printing are used to simplify the processing method and raise the assembly yields. Contact resistance, volume resistivity, high frequency performance, thermal conductivity and mechanical properties were measured and compared with metal filled conductive adhesive and traditional solder paste.

A research project at Linnaeus University focuses on optimizing theadhesives joints between wood and glass, with the aim of obtain stiffcomponents that can act as a load and stabilizing elements and still betransparent. But there is, however, still a lack of knowledge regarding theadhesive materials which need to be further investigated. This thesis focused on testing six different adhesives in relaxation and todetermine the viscosity (η) and modulus of elastic (MOE, E). Viscosity andMOE are then used in combination in a standard linear solid model (SLS)describing the viscoelasticity mathematically. Figures and tables are used topresent the results and the evaluation. The so determined parameters can beused in e.g. finite element models for the design of load bearing timber glasscomposites.

A series of studies on monomer to polymer conversion in adhesive systems was undertaken using micro-Raman spectroscopy. A database of micro-Raman spectra was compiled for identification of tooth tissues and materials. The degree of conversion was assessed as a function of time and light source. Linear and two-dimensional micro- Raman characterisations of the adhesive-dentine and resin-based composite-adhesivedentine interfaces were performed. The degree of monomer to polymer conversion of adhesive systems was correlated with the amount of eluted monomers obtained by highperformance liquid chromatography. The degree of conversion varied significantly depending on adhesive chemical composition, curing time and light source. It was impossible to specify one curing time applicable to all adhesive systems, due to differences in conversion kinetics. In general, conventional halogen light-curing units at twenty seconds curing time produced similar or higher degree of conversion in adhesive systems compared to high-power LED units at ten seconds. Significantly higher monomer conversion was found in the adhesive layer compared to the hybrid layer in both etch-and-rinse and self-etch systems. Etch-and-rinse adhesive systems formed thicker hybrid layers compared to self-etch systems. Micro-Raman spectroscopy gave a more precise indication of dentine demineralisation and adhesive penetration than scanning electron microscopy and indicated that the hybrid layer is a gradual transitional zone between the adhesive layer and un-affected dentine. The absolute amount and weight percent of eluted monomers varied in all tested adhesive systems. In most adhesive systems, more than 90% of eluted monomers were detected within the first one hour of immersion. Overall, no correlation was found between the degree of conversion and the amount of eluted monomers.

This study was made to determine the advantages of the use of epoxy resins in the industrial arts laboratory. The purpose of this study was to determine the feasibility of using epoxy resins as a wood adhesive. Data was gathered from texts, periodicals, and unpublished data. Tests were conducted using epoxy samples acquired from three epoxy manufacturers on three different woods and joints. The study discusses the advantages and disadvantages of using epoxy resins as a wood adhesive and the material and equipment necessary for the use of epoxy resins. Strength tests were performed on the joints adhered with epoxy and on joints adhered with white glue. A hand operated high tensile strength machine was used to conduct the tests. Epoxy Resins were found, in most cases, to give a more durable bond than white glue. Further studies should be made using epoxy resins as adhesives for metal, glass, plastic, and other materials used in the industrial arts laboratory.

Master of Science / Department of Grain Science and Industry / Xuzhi Susan Sun / Large amount of fiberboard are used for packaging applications every year, which generate a large amount of solid wastes causing environmental pollution if these packaging materials are not recycled. Also, a large amount of wood are needed for making fiberboard, which is limited resource in the earth. Reducing the weight of fiberboard and recycling the fiberboard materials are two methods to save quantities of wood fiber in fiberboard manufacture, which benefit the environment and economy. Besides, most adhesives used for producing the fiberboard contain environmental hazardous chemicals. It is necessary to develop new technology to produce cellulosic fiberboards with environmental friendly bio-based adhesives. The soybean is an agricultural product, and its resource is abundant. Soybean protein is a bio- material that offers an alternative to the existing synthetic adhesives to reduce petroleum dependence of the U.S. energy strategy. The newly developed soy-based adhesive is also competitive in cost. Material cost based on food-grade soybean protein is around 20 cents/Lb. The cost of commercial PF resin is about 14 ~ 17 cents/Lb. Price of hot-melt adhesive for fiberboard is around $6/Lb. In this study, soybean protein was modified with sodium dodecyl sulfate as an adhesive for two bio-based fiberboards products, medium density fiberboard by dry processing and light weight cardboard by wet processing. The mechanical and water soaking properties of these cellulosic fiberboards were stronger than or as same as commercial solid fiberboard. This research suggests that these cellulosic fiberboards with modified soybean protein based adhesive have great potential as alternative to current commercial fiberboard.

Orientador: Sandro D, Mancini / Banca: Sandra Andrea Cruz / Banca: Rogerio Scatena Biscaro / Resumo: O processo de fabricação das pás de turbinas eólicas envolve a colagem de estruturas fabricadas em plásticos reforçados com fibra de vidro. Neste trabalho foram analisadas os três principais tipos de adesivos estruturais utilizados pelos fabricante de pás (epóxi, poliuretano e metil-metacrilato), com o objetivo de desenvolver critérios que auxiliem na seleção de adesivos e de tratamentos superficiais aplicados às estrutuaras a serem coladas. A caracterização dos adesivos envolveu dois tipos de ensaios mecânicos: o cisalhamento de juntas de sobreposição simples e a clivagem de juntas adesivas. Dois tipos de tratamento das superfícies dos aderentes foram utilizados: camada de sacrifício removível (peel-ply) e abrasão. Também foi realizada a análise dos modos de falha das juntas ensaiadas como auxílio de compatibilidade entre adesivo e substrato. Os resultados mostram que o tratamento via peel-ply foi o mais eficiente para as juntas coladas com epóxi e testadas em cisalhamento, ao apresentar um aumento de 28% na resistência em relação às superfícies sem tratamento. Imagens de microscopia eletrônica de varredura sugerem que esse tratamento gerou uma área maior de contato em relação à superfície não tratada e que causou menos danos à superfície do aderente do que o método abrasivo. Os grupos colados com adesivo metil metacrilato, independentemente do tipo de tratamento, obtiveram os maiores valores nos ensaios de clivagem, cerca de 170% superiores aos demais grupos. Para estruturas de pás corretamente projetadas para evitar cargas de peeling em suas juntas adesivas, este trabalho mostra que a melhor opção são aderentes tratados com peel-ply e colados com epóxi. Contudo, um plano de testes deve ser elaborado sempre que houver a necessidade do emprego de um novo adesivo ou método de preparação superficial / Abstract: The manufacturing process of wind turbine blades involves the bonding of structures made of glass reinforced plastic. This work analyzes the theree main types of structural adhesives used by blades manufactures (epoxy, polyurethane and methyl methacrylate), with the goal of developing criteria to assist in the selection of adhesives and surface treatments applied to the structures to be bonded. The characterization of the adhesives involved two types of mechanical tests: single lap shear joints and cleavage of adhesive joints. Two types of surface treatment of the adherents were used: removable sacrifical layer (peel-ply) and abrasion. The joint failure mode analysis was also carried out as an aid to the study of compatibility between adhesive and substrate. The results show that treatment via peel-ply was the most efficient for epoxy bonded substrates tested in shear, by presenting a 28% increase in strengh compared to untreated surfaces. Images of scanning electron microscopy suggest that this treatment led to a larger area of contact relative to untreated surfaces and caused less damage to the substrate's surface than the abrasive method. The groups bonded with methyl methacrylate regardless the type of treatment, had the highest values in the cleavage test, approximately 170% higher than other groups. For propertly designed blades, that avoid peeling loads in their adhesive joints, this work shows that the best option are substrate treated with peel-ply and bonded with epoxy. However, a test plan should be prepared whenever there is the necessity of using a new adhesive or method of surface preparation / Mestre

The dental field shows proliferation in the market of new adhesives. The purpose of this study is to evaluate the mechanical properties on total restoration, based on the manufacturer's technical specifications, experimental and mechanical test results. The optimal dentist's selection will be when the most appropriate adhesive can be chosen for one specific restoration, avoiding wasted time, material and exposure to marginal infections with a failure restoration. This research was developed in stages. The first step is the study of the tooth morphological information. Following, there is the structure identification type and the chemical composition of six different pure adhesives. Next, perform the X-R Diffraction, Energy Disperse Spectroscopy (EDS), and Scanning Electron Microscopy (SEM). The final step is to perform the mechanical test, computer simulation, and discuss the results to obtain the best dental adhesive with and the new finding. Result: The samples show an amorphous structure and a chemical composition in the X-R Diffraction, SEM and EDS experiments. The mechanical test shows real mechanical properties under tension and sheer rupture stress. Poisson ratio, strain, and another relationship will be used in the computer simulation test. Results will be reflected in the Discussion and Conclusion. Significance: The first conclusion is that the amorphous structure is present in all six adhesives experiments. In addition, it shows strong possibilities of bonding with another neighbor's molecules. The discussion will be extended to the bonding advantages for this type of structure in the total dental restoration. / Findings: First, we found that the time delay of photo polymerization was controlled with the variable water evaporation of the etching treatment. In addition, it was found that the variable size of the wavelength of the curing light obtained better molecular organization and avoided internal stress and bonding defect. Lastly, the chemical composition was a variable that provided the opportunity to predict the type of bond and strength. / by Raul Vargas. / Thesis (Ph.D.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.