On Thursday, November 23, 2017, Mao Nguyen Dang, a PhD student at the Laboratoire d'Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), will defend his thesis on "Bamboo fiber / powder panels for building construction: elaboration and hygrothermal characterization", supervised by LOCIE researchers Anne-Cécile Grillet and Monika Woloszyn. The presentation will take place at 2pm, in room 200 of the Belledonne building, on the Bourget-du-Lac university campus.
thesis summary
Reducing energy consumption for future buildings by using insulation materials based on bio-sourced materials is one of today's research interests. This work evaluates the performance of new thermal insulation materials based on bamboo fibers/powders and adhesives based on proteins and sodium lignosulfonate, with the addition of inorganic adsorbents such as sepiolite and attapulgite. The materials can be used inside buildings as humidity control materials due to their buffering capacity. In this way, they can help save energy consumption by reducing the use of heating/cooling systems.
Firstly, the conditions for processing these materials on a hydraulic press were optimized, as were the proportions of the various constituents. Next, the microstructure of the materials was studied using mercury porosimetry (MIP), scanning electron microscopy (SEM) and infrared spectroscopy (IR) to understand the interactions between all the components and assess the effect of the porous structure on the hygrothermal performance of the boards. The hygrothermal properties of these innovative insulating materials, such as vapour sorption kinetics, buffering properties, water vapour permeability, vapour sorption isotherms and thermal conductivity were analyzed. Moisture buffering values (MBV) of the panels with glue belong to an "excellent" category of 2.0 to 3.9 g / (m2% RH) compared to 1.7 g / (m2% RH) for the panel without binder. Vapor absorption and desorption capacity at different relative humidity levels follow the same trend, i.e. higher capacities for panels with glue.
Thermal insulation properties depend on density, relative humidity and variation in moisture content. The mechanical properties of panels are considerably enhanced when sodium lignosulfonate is added to protein glue, due to the chemical interactions between the components. However, these same mechanical properties tend to decrease when mineral absobents are added due to the lack of cohesion in bamboo planks. The mold index and the moisture levels/time couples required for mold growth on board surfaces are also studied. The final part is a numerical simulation on Dymola software using the Modelica language. A numerical model was used to simulate the phenomena observed under experimental conditions. Comparisons between numerical and experimental results under controlled conditions show a good correlation for temperature and hygric properties of the panels Keywords: bamboo panels, biomaterials, thermal insulation, hygrothermal performance, hygroscopic materials, heat and moisture transfer
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Contact: Anne-Cécile Grillet