On Thursday, November 23, 2017, Mao Nguyen Dang, a doctoral student atthe Laboratory for Optimization of Design and Environmental Engineering(LOCIE), will defend his thesis on "Bamboo fiber/powder panels for building construction: development and hygrothermal characterization," supervised by Anne-Cécile Grillet and Monika Woloszyn, researchers at LOCIE. The defense will take place at 2:00 p.m. in Room 200 of the Belledonne Building on the Bourget-du-Lac university campus.
thesis abstract
Reducing energy consumption in future buildings by using insulation materials made from bio-based materials is one of the current areas of research interest. This work evaluates the performance of new thermal insulation materials made from 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 moisture control materials due to their buffering capacity. Thus, they can contribute to energy savings by reducing the use of heating/cooling systems.
First, the conditions for implementing these materials on a hydraulic press were optimized, as were the proportions of the various components. Next, the microstructure of the materials was studied using mercury porosimetry (MIP), scanning electron microscopy (SEM), and infrared spectroscopy (IR) in order to understand the interactions between all the components and evaluate the effect of the porous structure on the hygrothermal performance of the panels. The hygric properties of these innovative insulating materials, such as vapor sorption kinetics, buffer properties, water vapor permeability, vapor sorption isotherms, and thermal conductivity, were analyzed. The moisture buffer values (MBV) of the panels with adhesive 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 adhesive.
Thermal insulation properties depend on density, relative humidity, and moisture content variation. The mechanical properties of the panels are significantly increased when sodium lignosulfonate is added to the protein glue due to chemical interactions between the components. However, these same mechanical properties tend to decrease when mineral absorbents are added due to the lack of cohesion in bamboo boards. The mold index and the humidity/time levels required for mold growth on panel surfaces are also studied. The final part is a numerical simulation using Dymola software via 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 good correlation for the 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