5 research outputs found
Green gluing of tropical wood Part III: X-Ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) analysis of Frake and Ayous green wood's Glue line
Get PDFGreen gluing of tropical wood Part III: X-Ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) analysis of Frake and Ayous green wood’s Glue line. Emmanuel Njungab1,2, René Oum Lissouck2,4, 5Christine Labrugère, Ntede Ngah Hippolyte2, Régis Pommier3, Louis Max Ayina Ohandja2, Joseph Noah Ngamveng1 1 Laboratory of Macromolecular Chemistry (LCMA), Faculty of science, The University of Yaoundé 1, Cameroon. 2 Laboratory of Mechanics, Materials and Structures (LMMS), ENSP, The University of Yaoundé 1, Cameroon. 3 Institute of Mechanics and Engineering (I2M-GCE), The University of Bordeaux 1, France. 4 National Centre of Scientific Research (CNRS), UMR 5295, France. 5Centre de Caractérisation des Matériaux Avancés (ICMCB, CNRS-UPR), The Université of Bordeaux 1 Abstract: We have recently succeeded to bond two tropical african woods Ayous and Frake in the green state by the glulam technique using a one component (1C-PU) polyurethane adhesive. Durable bond line was achieved and succeeds to meet the structural standard requirement. Scanning electron microscopy performs on the glue line show a good embedding of the glue on the wood fibers. X-ray photoelectron spectroscopy also referred to as Electron spectroscopy for chemical analysis (ESCA) and Fourier transform infrared spectroscopy were used to investigate the interaction of both tropical woods with adhesive. Unlike theoretical expected urethane functional group, xps analysis indicated a high proportion of non hydrolyze urea group and hydrogen bonding of nitrogen (N) at 399,5 eV and 400,5 eV respectively. This foreseen that polyurea polymers and hydrogen bond are the most probable bond to strengthen the gluline. Key words: Green gluing, Tropical woods, Sanding, 1C-PU, XPS, FTIR, Polyure
Investigation of green-glued laminated timber from the Congo Basin: durability, mechanical strength and variability trends of the bondlines
No full textThe development of glulam may give complementary, added-value to an important part of the timber production in the Congo Basin. Nevertheless, the high humidity in which these timbers operate may cause problems such as cracks and severe deformations if they are not suitably bonded. Moreover, there is a lack of knowledge concerning the refined design of the bondlines of glulam assembling from the Congo Basin hardwoods. We investigated the durability, mechanical strength, and variability features of the bondlines, manufactured under higher moisture conditions. Eight hardwood species with very different properties were selected. A one-component polyurethane adhesive was used. Industrial gluing parameters were kept constant. Delamination, shear tests and analysis of bondlines thickness were carried out. Multivariate analysis and a goodness-of-fit test of the strength variability of the bondlines were performed. Optimum bondlines thicknesses were obtained. Their durability exhibited satisfactory trends up to a density of 750 kg/m3. The behaviour of the bondlines can operate in three homogeneous groups. In each of them, the variability of the shear strength can be properly modelled using a 3-parameter Weibull probability. Wood failure trends were in accordance with several international requirements. The density value of 750 kg/m3 appeared as critical for the compatibility between the shear strength, the durability and the bondlinesthickness. The overall results showed the ability of several tropical timber species to be valorised in green-glulam applications. Moreover, the findings unlock new trends concerning a reliable and safe design of tropical glulam as a structural wood-based product
