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Gewählte Master / Diploma Thesis:

Peter Bliem (2017): Characterization of foam properties of 2C-polyurethane for wood bonding.
Master / Diploma Thesis - Institut für Holztechnologie und Nachwachsende Rohstoffe, BOKU-Universität für Bodenkultur, pp 103. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Abstract:
In this master thesis, the mechanical foam properties of a two-component polyurethane were systematically investigated with the aim of using it for wood bonding with gap filling properties. The mechanical properties of the wood adhesive bonds are strongly dependent on the strength, stiffness and homogeneity of the adhesive foam induced, which in turn is influenced by various factors. These influencing factors are the ratio of isocyanate to polyol, the amount of the additional water, water available from the wood substrate (wood moisture content), the press temperature and the thickness of the foam. The longitudinal tensile shear strength and the shear modulus were measured using lap-joint specimens with defined bond-line thickness allowing the adhesive to foam between the adherents. The data were evaluated with statistical analysis software, whereby possible correlations and/or interrelationships of influencing factors with the response values (strength and stiffness) were investigated more closely. Subsequently, constellations in which the best adhesive-foam properties could be achieved, were derived. In principle, for low foam thickness (0.5 mm) the highest strength and stiffness values were achieved with those foams which were produced at a low press temperature (20 °C), a high wood moisture content (21 %), an average additional water content (5.5 %) and a high content of isocyanate (>85 %). An increase in the press temperature or the foam thickness leads to a major drop in the mechanical foam properties, whereby both lower wood moisture content as well as lower amount of isocyanate leads also to a reduction in performance. It has also been observed that with a low foam thickness (0.5 mm), a relatively high wood failure occurs, especially in the case of the samples using a low press temperature (20 °C).

Beurteilende(r): Konnerth Johannes
1.Mitwirkender: Van Herwijnen Hendrikus

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