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Entwicklung eines faltbaren Werkstoffverbundes auf Furnierbasis

dc.contributor.advisorKharazipour, Alireza Prof. Dr.
dc.contributor.authorAckermann, Timo
dc.titleEntwicklung eines faltbaren Werkstoffverbundes auf Furnierbasisde
dc.title.translatedDevelopment of a foldable material composite based on veneerde
dc.contributor.refereeKharazipour, Alireza Prof. Dr.
dc.description.abstractengThe growing demand for durable, sustainable, regionally and "fairly" produced products has been rising steadily since the early 2000s, especially products made of wood are becoming more and more popular. Against this background, together with the company Josef Wochner GmbH & Co KG, Rosenfeld Heiligenzimmern, the idea was born to develop a material based on real wood veneers of alder (Alnus glutinosa L) and oak (Quercus petraea (matt) Liebl. respectively Quercus robur L. ), bonded with a flexible middle layer, which can be used in the packaging environment. In order to ensure the highest possible dimensional stability, a 5-layer structure was aimed at, each consisting of two cross-glued veneer sheets on a flexible middle layer. This composite material named „Faltfurnier“ and its basic materials were investigated and evaluated with regard to their mechanical-technological and chemical properties. A material combination of veneers and a PVC foil in the middle layer was selected. A PVAc-based adhesive and a thermoplastic adhesive film on PU basis were used for bonding the different layers. In a first step, the tensile strength of the PVC foil used was investigated under different starting conditions. Here it was shown that the direction of production has a significant influence on the tensile strength. Thus, parallel to the direction of production significantly higher strengths than perpendicular to the direction of production were found. An influence of the process temperature could not be proven. Within different test series the surface soundness was used as a criterion to define an optimal pressing time, to evaluate the quality of the bonding by means of thermoplastic adhesive film of the veneers on PVC film as well as the bonding of the cross grain and face veneers by means of the adhesive systems PVAc and adhesive film. The tests resulted in an optimal pressing time of 120 s and incomparison significantly lower surface soundness in the test series with oak than with alder on PVC foil. Furthermore it could be shown that the bonding of the cross grain and face veneers can be replaced by a thermoplastic adhesive film, but leads to lower strengths. A positive aspect here is that the more economic production using the one-shot process would thus be possible. Due to the differences in the strength of the bond between alder and oak, the veneers were chemically characterised with regard to their pH values, buffer capacities and extractives, and reasons for the lower strength of oak on PVC film were determined. An influence of the surface structure of the veneers on the surface soundness could not be proven with certainty. Finally, a 5-layer overall composite of alder veneer on PVC foil was produced and examined with regard to its bending strength and bending modulus of elasticity, durability of the folding groove as well as its behaviour in strong alternating climate. The tests showed that the bending strength and bending modulus of elasticity were significantly higher when tested perpendicular to the grain direction of the face veneer than when tested parallel to the grain direction. Cracks and signs of fatigue in the folding groove only became apparent on average after 4,436 repetitions of the folding process using a door testing machine, and the material remained dimensionally stable except for slight warping on its head sides when stored in a highly variable
dc.contributor.coRefereeMai, Carsten Prof. Dr.
dc.subject.engfoldable veneerde
dc.subject.engadhesive film on PU basisde
dc.subject.engmaterial compositede
dc.subject.engmaterial composite based on veneerde
dc.affiliation.instituteFakultät für Forstwissenschaften und Waldökologiede
dc.subject.gokfullForstwirtschaft (PPN621305413)de

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