Franck Michaud

Wood and engineered wood products can be used to replace non-renewable materials in construction and furniture, contributing to a more sustainable society. This study aimed to assess the potential of Pinus patula wood for the production of frames and edge glued panels, and to maximize production process variables, adhesive weight, and pressure, in order to generate a product with adequate quality at the lowest cost. environmental. Fingerjointing and edge gluing were performed. The finger joint gluing was carried out industrially using PVA adhesive. Edge gluing was carried out on a laboratory scale under 18 experimental conditions: 16 with Pinus patula and 2 with Pinus taeda (control). The variables studied were the glue type (PVA and EPI), grammage (160, 180, 200, and 220 g.m^-2), and pressure (7 and 10 kgf.cm^-2). The finger joint gluing quality was assessed by flexural and tensile tests (ASTM, 2019) and edge bonding by shear strength (ES, 2009). The results showed that Pinus patula has potential for the production of frames and edge glued panels, and that process variables can be maximized when using EPI adhesive.

Depuis sa première édition en 2012, cet événement est organisé tous les ans dans un nouveau campus, et est une opportunité pour ses participants de découvrir les différents sites nationaux de recherche en sciences du bois. En 2024, Nantes nous accueille en organisant cette 13ème édition des Journées Scientifique Annuelles du GDR 3544 Sciences du Bois. Les sciences du bois sont pratiquées actuellement par une communauté très diverse par ses disciplines, thématiques et contextes institutionnels. Les objectifs du GDR 3544 Sciences du Bois sont de rassembler cette communauté autour de thèmes scientifiques transversaux, de proposer des actions de coordination en matière de pédagogie, de mettre en place des partages de ressources et d’établir des relations avec la communauté scientifique nationale, voire internationale francophone, et les acteurs professionnels.L’objectif des journées scientifiques du GDR est de partager une culture commune. Cette manifestation s'est tenue les années précédentes à Montpellier (2012), Champs-sur-Marne (2013), Nancy (2014), Clermont-Ferrand (2015), Bordeaux (2016), Nantes (2017), Cluny (2018), Épinal (2019) et Grenoble (2020), Montpellier (2021), Nice (2022), Limoges (2023). A noter que les actes de toutes ces manifestations sont accessibles librement sous HAL. (https://hal.science/)En 2024, cette manifestation a été organisée à Nantes au sein de l’ESB et en particulier par les chercheurs et enseignants-chercheurs du LIMBHA (Laboratoire Innovation Matériaux Bois HAbitat), dont les recherches s‘orientent autour de deux axes : « l’économie circulaire » et « le confort du cadre bâti ». La participation à ces journées a été un record avec plus de plus de 240 personnes dont 18 participants étrangers et une trentaine d’industriels auxquels s’est rajoutée la présence exceptionnelle de 250 étudiants de l’ESB.Le fil rouge de ces journées était le thème « De l'arbre au panneau, ou la circularité des flux matières bois ». Ces journées ont consisté en des exposés invités, de près de 80 présentations éclairs introduisant autant de posters. Des réunions de 14 Groupes de Travail à l'initiative des participants se sont déroulées ; dont certaines, comme « Panneau de Fibres », innovaient la formule pour la première fois. Des possibilités de découverte des activités des laboratoires du campus hôte et d’entreprises et lieux culturels locaux ont été organisées sur une après-midi, toujours sur le thème du bois, bien sûr ! Deux belles innovations pour cette édition 2024 :i)l’organisation d’une session orientée vers les industriels dont plus d’une trentaine ont été invités à participer, ii)l’organisation de plusieurs Master Class filmées par des ténors de notre communauté à destinations des nombreux étudiants venus les écouter. Ces interventions seront rendues disponibles en particulier sur notre site web.Le GDR 3544 « Sciences du Bois » remercie particulièrement le comité local d’organisation de l’ESB de Nantes qui a œuvré pour la réussite de cet évènement, les soutiens financiers institutionnels et privés, ainsi que l’ensemble des membres du comité scientifique qui ont pris le temps de relire les résumés des communications afin de garantir la qualité des textes que vous retrouverez dans ces actes.

Biorefineries have many possible designs and therefore, present varied benefits in regards to sustainable development. Evaluating these biorefineries is central for the domain, and, as small-scale biorefineries (SSB) are commonly opposed to the large ones, specifying the concept of scale of a biorefinery is essential as well. However, there is no consensual definition of the “scale”, and the meaning of the term changes with the context. This paper presents a methodology to specify the concept of scale by grouping various biorefineries processing lignocellulosic biomass according to factors related to feedstock, process, economy and mobility of the facility, without any predetermined pattern. Data from 15 operational biorefineries are analyzed using a multivariate analysis combined with a hierarchical clustering. The classification obtained categorizes biorefineries into four design classes: smallest, small, hybrid and large scale. Small-scale biorefineries are characterized by a small investment cost (less than 2 M€), a low processing capacity (less than 100 t/day) and a low process complexity, while the end-products’ added value is variable. The mobility of the plants is a sufficient, but not necessary, criterion to have a small-scale biorefinery. Finally, the designs of the investigated biorefineries can be explained by two main trade-offs: one between the mobility and the processing capacity-investment cost, and the other between the process complexity and the added value.

In this investigation, sludge fibre waste (SFW) and Kraft lignin powder (KLP) are introduced into polylactic acid (PLA) matrix biocomposites. These alternative materials allow for both the reuse of fibre waste from paper mill sludge and a reduction in the amount of high-cost biopolymer used in the same volume. Proportions from 10 to 40 wt.% of SFW with the addition of 2.5% and 5% of KLP are incorporated in PLA by extrusion and injection moulding. The thermogravimetric properties, water absorption, tensile and flexural properties, and morphology of the fabricated biocomposites were investigated. According to the results, KLP contributes to thermically stabilising the loss resulting from the incorporation of SFW. Flexural and tensile tests reveal a more pronounced decrease in strength with an SFW ratio above 10%. The modulus of elasticity increases significantly with an SFW ratio above 20%. The strength properties are stabilised with the addition of 5% KLP. The addition of KLP presents a tendency to reduce water absorption obtained by the incorporation of SFW into biocomposites. Scanning electron micrographs evidence that KLP improves the interfacial adhesion by reducing the voids between fibres and PLA.

In this study, the viability of acetylation in cellulose fibers waste (CFW) from pulp and paper mill sludge was investigated in comparison to bleached cellulose fibers (BCF). Four acetylation methodologies were applied. The inorganic ash composition of the CFW was determined by Energy Dispersive X-ray Spectrometry (EDS). The Degree of substitution (DS) of the acetylated fibers and their characterization using Fourier Transformed Infrared (FT-IR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), and Scanning electronic microscopy (SEM) were carried out. Results showed that the different acetylation methods are not effective for the esterification of CFW largely due to a high mineral content in their composition. The acetylation promoted the removal of the inorganic content in the CFW resulting in low efficacy levels. In BCF, higher efficiency levels were achieved, varying according to the methods. The different acetylation methods showed an efficiency range from 0.02 to 1.76 depending on the type of fiber.

The weathering of wood through abiotic factors has been extensively studied. Much less research has been conducted on the influence of biotic factors on wood in exterior use that is not in ground contact, i.e. use class 3. There is especially a lack of research concerning the influence of the presence of bacterial and fungal communities on the weathering process of wood. The project aim is to identify any synergistic effects between biotic factors such as bacteria (Actinomycetes and Eubacteria) and fungi (Basidiomycota and Ascomycota) and abiotic factors such as light, temperature and moisture on the weathering of wood surfaces in use class 3. This paper presents results such as the amount of colony forming units (CFU), environmental scanning electron microscope analysis, colour changes and moisture content (MC) from preliminary experiments where wood surfaces were either naturally or artificially weathered. In order to study the interactions of fungi and bacteria on wood during the weathering process, the presence of microorganisms on natural weathered oak and Douglas fir surfaces had to be validated first. With the help of a surface contact test, microorganisms on the wood surfaces were transferred to agar plates and consequently incubated so that they could grow in appropriate conditions. Once the microbiological colonies had developed sufficiently, they were separated by selecting sections from the colonies and replated on fresh agar. A microcosm scale experiment, meaning the transfer of one specific bacteria and one fungi together in one petri dish, was carried out. This trial revealed that certain bacteria have an influence on the growth rate of certain fungi. In addition, an artificial weathering test was carried out in a QUV, which allows the degradation of samples using specific and known abiotic degrading parameters. The observation of the artificial weathered wood samples revealed that microorganisms are most definitely present in the QUV test apparatus and may influence the test results.

The use of scientific knowledge on waste wood management is the main factor that facilitates the responsible use of recovered wood respecting the environment. Nowadays, numerous scientific results are generated and published by universities and research institutions; but small quantities are exploited by nonscientific people. This problem is due to the difficulty of transfer and assimilation of this knowledge in its current representation. In this paper, we propose a new structure and representation of both type of scientific knowledge (declarative and procedural) to facilitate its transfer to non-scientific people through a hypertext electronic knowledge-book. The declarative scientific knowledge has been represented by concept maps and hierarchically structured through semantic relationships and the procedural scientific knowledge has been represented by technical sheets.